FP Huang | The University of Hong Kong (original) (raw)

Papers by FP Huang

Research paper thumbnail of The Evolutionary Role of the IL-33/ST2 System in Host Immune Defence

Archivum Immunologiae et Therapiae Experimentalis, 2013

Interleukin (IL)-33 is a recently identified pleiotropic cytokine, which can orchestrate complex ... more Interleukin (IL)-33 is a recently identified pleiotropic cytokine, which can orchestrate complex innate and adaptive immune responses in immunity and disease. It has been characterized as a cytokine of the IL-1 family and affects a wide range of immune cells by signalling through its receptor ST2L. Accumulating evidence suggests a crucial role of IL-33/ST2 in inducing and modifying host immune responses against a variety of pathogens including parasites, bacteria, viruses and fungi as well as sterile insults of both endogenous and exogenous source. In this review, we endeavour to give a comprehensive overview of the current knowledge about the role of IL-33 and its receptor ST2 in host defence against infections.

Research paper thumbnail of Uptake of Antigens from the Intestine by Dendritic Cells

Annals of the New York Academy of Sciences, 2004

The intestinal immune system responds to ingested antigens in a variety of ways, ranging from tol... more The intestinal immune system responds to ingested antigens in a variety of ways, ranging from tolerance to full immunity. How T cells are instructed to make these differential responses is still unclear. Dendritic cells (DCs) sample enteric antigens in the lamina propria and Peyer's patches, and transport them within the patch or to mesenteric nodes where they are presented to lymphocytes. It is probable that DCs also transmit information that influences the outcome of T cell activation, but the nature of this information and the factors in the intestine that regulate DC behavior and properties are far from clear. We have developed a model in the rat that permits analysis of DCs actually in the process of migration from the intestine to mesenteric nodes. In this paper we will review those aspects of our research that relate to antigen uptake and discuss these in the context of other experimental systems.

Research paper thumbnail of Development of dendritic cell-based tumor vaccines with high efficacy by targeting the negative regulators of DC functions: Guiding the 'misguided

Invited speaker - ScientificTracks AbstractsThe DC-based therapeutic vaccine has been a theoretic... more Invited speaker - ScientificTracks AbstractsThe DC-based therapeutic vaccine has been a theoretically attractive approach being explored for cancer treatment during the last 2 decades. Its clinical application, however, has thus far been limited by the lack of achievable general efficacy and consistency. One of the major obstacles is believed to be the immunosuppressive tumor microenvironment these live DC cells are subjected to. To develop a novel DC-based tumor vaccine with high efficacy and stability, we have designed, tested and compared different ways of enhancing DC immunogenicity by functional conditioning of the cell vectors, targeting both the positive and negative arms of immune regulation. Findings from our studies indicate that the most effective way to enhance the vaccine efficacy is to block the negative regulators of DC functions. We showed that the vaccines delivered by DCs devoid or knock-down of IL-10, a potent immunosuppressive cytokine expressed by DC, were super...

Research paper thumbnail of Serum levels of IL-33 and soluble ST2 and their association with disease activity in systemic lupus erythematosus

Rheumatology, 2009

Objective. IL-33 has recently been found to be the specific ligand of ST2, an IL-1 receptor famil... more Objective. IL-33 has recently been found to be the specific ligand of ST2, an IL-1 receptor family member that is selectively expressed in Th2 cells and mediates Th2 response. This study aims to measure the serum levels of soluble ST2 (sST2) and IL-33 in patients with SLE and to examine their association with disease activity. Methods. Seventy SLE patients were evaluated for disease activity, determined by SLEDAI, levels of anti-dsDNA antibody, C3 and C4. Fifty-seven patients were evaluated longitudinally on a second occasion. IL-33 and sST2 were measured by sandwich ELISA in the 127 SLE serum samples and compared with 28 age-and sex-matched healthy controls. Results. Serum sST2 level was significantly higher in active SLE patients [0.51 (0.18) ng/ml] compared with inactive patients [0.42 (0.08) ng/ml] (P = 0.006) and normal controls [0.36 (0.13) ng/ml] (P < 0.001). sST2 level correlated significantly with SLEDAI, anti-dsDNA antibody and prednisolone dosage, and negatively with C3. Linear regression analysis showed that serum sST2 level was an independent predictive factor for modified SLEDAI, excluding anti-dsDNA and complement score after controlling for age, sex, glomerular filtration rate and prednisolone dosage (regression coefficient: 8.5; 95% CI 2.6, 14.3) (P = 0.005). Serum sST2 level was sensitive to change in disease activity longitudinally, with an effect size of 0.29. Elevated serum IL-33 was comparable in frequency (4.3 vs 7.1%; P = 0.62) and levels (P = 0.53) between SLE patients and controls. Conclusions. Elevated serum sST2 level in SLE patients was found to correlate with disease activity and was sensitive to change, suggesting a potential role as a surrogate marker of disease activity.

Research paper thumbnail of Mice lacking inducible nitric oxide synthase are not resistant to lipopolysaccharide-induced death

Proceedings of the National Academy of Sciences, 1995

Nitric oxide produced by cytokine-inducible nitric oxide synthase (iNOS) is thought to be importa... more Nitric oxide produced by cytokine-inducible nitric oxide synthase (iNOS) is thought to be important in the pathogenesis of septic shock. To further our understanding of the role of iNOS in normal biology and in a variety of inflammatory disorders, including septic shock, we have used gene targeting to generate a mouse strain that lacks iNOS. Mice lacking iNOS were indistinguishable from wild-type mice in appearance and histology. Upon treatment with lipopolysaccharide and interferon gamma, peritoneal macrophages from the mutant mice did not produce nitric oxide measured as nitrite in the culture medium. In addition, lysates of these cells did not contain iNOS protein by immunoblot analysis or iNOS enzyme activity. In a Northern analysis of total RNA, no iNOS transcript of the correct size was detected. No increases in serum nitrite plus nitrate levels were observed in homozygous mutant mice treated with a lethal dose of lipopolysaccharide, but the mutant mice exhibited no significan...

Research paper thumbnail of Production of nitric oxide in the synovial membrane of rheumatoid and osteoarthritis patients

Journal of Experimental Medicine, 1996

We have demonstrated spontaneous nitric oxide (NO) production by primary synovial cultures from r... more We have demonstrated spontaneous nitric oxide (NO) production by primary synovial cultures from rheumatoid (RA) and osteoarthritis patients. Increased NO production followed addition of staphylococcal enterotoxin B. Immunochemical double staining with specific anti-human inducible NO synthase (iNOS) and nonspecific esterase (NSE), or anti-CD68 (markers for tissue macrophages) showed that although many lining layer cells in RA synovium expressed iNOS, most (approximately 90%) were NSE- and CD68-, with only a minor population (approximately 10%) which were iNOS+, CD68+/NSE+. These data demonstrate the capacity for high output of NO by human synovial tissue and show that, although human macrophages can express high levels of iNOS, the majority of cells expressing iNOS are fibroblasts. We also report that synoviocytes, and macrophage cell lines, cultured with the NO donor, S-nitroso-acetyl penicillamine, produced high concentrations of tumor necrosis factor (TNF)-alpha. These results su...

Research paper thumbnail of Guidelines for the use of flow cytometry and cell sorting in immunological studies

European journal of immunology, Oct 1, 2017

Guidelines for the use of flow cytometry and cell sorting in immunological studies

Research paper thumbnail of Mice defective in Fas are highly susceptible to Leishmania major infection despite elevated IL-12 synthesis, strong Th1 responses, and enhanced nitric oxide production

MRL/MP-lpr/lpr (MRL/lpr) mice have a single mutation (lpr) of the fas apoptosis gene. The mutant ... more MRL/MP-lpr/lpr (MRL/lpr) mice have a single mutation (lpr) of the fas apoptosis gene. The mutant mice developed significantly smaller lesions than the wild-type mice at the earlier stage of infection with the intracellular protozoan parasite Leishmania major. However, while all the wild-type mice achieved complete lesion resolution, the disease in the mutant mice progressed inexorably. The mutant mice had more IL-12 and nitrite/nitrate in the serum than wild-type mice following infection. Lymphoid cells from infected MRL/lpr mice produced more IFN-gamma but less IL-4 and IL-5 than cells from MRL-+/+ mice. Peritoneal macrophages from the mutant mice also produced more IL-12 and NO after stimulation with LPS. Thus, Fas expression is essential for resistance against leishmaniasis, and Fas-mediated apoptosis may form an integral part of the Th1-mediated microbicidal function.

Research paper thumbnail of Mice defective in Fas are highly susceptible to Leishmania major infection despite elevated IL-12 synthesis, strong Th1 responses, and enhanced nitric oxide production

Journal of immunology (Baltimore, Md. : 1950), 1998

MRL/MP-lpr/lpr (MRL/lpr) mice have a single mutation (lpr) of the fas apoptosis gene. The mutant ... more MRL/MP-lpr/lpr (MRL/lpr) mice have a single mutation (lpr) of the fas apoptosis gene. The mutant mice developed significantly smaller lesions than the wild-type mice at the earlier stage of infection with the intracellular protozoan parasite Leishmania major. However, while all the wild-type mice achieved complete lesion resolution, the disease in the mutant mice progressed inexorably. The mutant mice had more IL-12 and nitrite/nitrate in the serum than wild-type mice following infection. Lymphoid cells from infected MRL/lpr mice produced more IFN-gamma but less IL-4 and IL-5 than cells from MRL-+/+ mice. Peritoneal macrophages from the mutant mice also produced more IL-12 and NO after stimulation with LPS. Thus, Fas expression is essential for resistance against leishmaniasis, and Fas-mediated apoptosis may form an integral part of the Th1-mediated microbicidal function.

Research paper thumbnail of Skin Allograft Rejection in Mice Lacking Inducible Nitric Oxide SYNTHASE1

Transplantation, 1997

During allograft rejection, up-regulation of cytokine-inducible nitric oxide synthase (iNOS) lead... more During allograft rejection, up-regulation of cytokine-inducible nitric oxide synthase (iNOS) leads to the production of large amounts of nitric oxide (NO). The net effect of NO on the alloimmune response is, however, difficult to predict because of its diverse biological effects, which include potentially opposing roles as an effector and immunoregulatory molecule. In this study, the role of iNOS on the in vitro and in vivo alloimmune response was defined using mutant mice that lack a functional iNOS gene. The ability of spleen cells obtained from iNOS-deficient mutants to proliferate and to produce cytokines in response to irradiated BALB/c stimulator cells was determined, and the rate at which iNOS-deficient mice were able to reject BALB/c skin allografts was observed. Spleen cells from homozygous iNOS-deficient (129xMF1)F1 mice, when compared with cells from heterozygous control mice, showed an increased in vitro proliferative response and produced substantially higher levels of interferon-gamma, and also more interleukin-2 and interleukin-12, in response to allogeneic stimulation. The kinetics of BALB/c skin graft rejection were comparable in heterozygous control animals and iNOS-deficient mice. Moreover, no net effect of iNOS on skin allograft rejection was apparent in mice treated with depleting monoclonal antibodies (mAb) to CD4 or CD8 T cells, either alone or in combination, or in mice treated with both anti-CD8 mAb and a neutralizing anti-tumor necrosis factor mAb. These results show that iNOS has an immunomodulatory effect on the in vitro alloimmune response but lack of iNOS has no net influence on the kinetics of murine skin allograft rejection in either unmodified recipients or recipients in which the early contribution of T-cell subsets and tumor necrosis factor-alpha to graft rejection has been abrogated.

Research paper thumbnail of An essential protective role of IL-10 in the immunological mechanism underlying resistance vs susceptibility to lupus induction by dendritic cells and dying cells

Rheumatology, 2011

Objective. To define the role of IL-10 in lupus pathogenesis, and to understand the immunological... more Objective. To define the role of IL-10 in lupus pathogenesis, and to understand the immunological mechanisms underlying resistance vs susceptibility to lupus disease induction by dendritic cells (DCs) and dying cells. Methods. Groups of IL-10-deficient and normal C57BL/6 mice were injected with syngenic DCs that had ingested necrotic cells prepared by either freezethaw cycle (DC/nec F/T) or heat shock (DC/nec H/S) procedures, or with DC or necrotic cells alone, or with PBS only. Disease development, including proteinuria and renal pathological changes, was monitored. Levels of autoantibodies against different lupusassociated nuclear antigens were measured by ELISAs, and IC deposition in the kidneys was confirmed by immunostaining. Results. No significant proteinuria was detected in the mice. However, striking renal pathological changes typical of IC-mediated GN were consistently observed in the DC/nec F/T-treated IL-10 À/À mice. These included glomerular hypercellularity and macrophage infiltration, renal IC deposition, circulating kidneyreactive autoantibodies and the presence of immunoglobulin G2 isotype-specific antibody complexes in the diseased kidneys. We demonstrated further that host-derived IL-10 was primarily responsible for protecting against the induction of pathogenic Th1 type of autoantibody responses in the mice. Conclusion. IL-10 protects against the induction of lupus-like renal end-organ damage by downregulating pathogenic Th1 responses.

Research paper thumbnail of The role of interleukin–15 in T–cell migration and activation in rheumatoid arthritis

Nature Medicine, 1996

Interleukin 15 (IL-15) is a novel cytokine with interleukin-2-like activity. It is also a potent ... more Interleukin 15 (IL-15) is a novel cytokine with interleukin-2-like activity. It is also a potent T-lymphocyte chemoattractant. Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by the presence of activated T lymphocytes, macrophages and synoviocytes in the synovial membrane. The mechanisms of T-cell activation in RA are currently unclear. We report the presence of high concentrations of IL-15 in rheumatoid arthritis (RA) synovial fluid and have demonstrated its expression in the synovial membrane lining layer by immunohistochemistry. RA synovial fluids were found to contain chemotactic activity, which was attributable in part to the presence of IL-15. Moreover, in a murine model, injection of recombinant IL-15 was found to induce a local tissue inflammatory infiltrate consisting predominantly of T lymphocytes. Synovial fluid T lymphocytes proliferate in response to IL-15, demonstrating that continued responsiveness to IL-15 is a feature of T cells after entry into the synovial compartment. These data suggest that IL-15 can recruit and activate T lymphocytes in the synovial membrane, thereby contributing to RA pathogenesis.

Research paper thumbnail of Altered immune responses in mice lacking inducible nitric oxide synthase

Nature, 1995

Nitric oxide (NO) is important in many biological functions. It is generated from L-arginine by t... more Nitric oxide (NO) is important in many biological functions. It is generated from L-arginine by the enzyme NO synthase (NOS). The cytokine-inducible NOS (iNOS) is activated by several immunological stimuli, leading to the production of large quantities of NO which can be cytotoxic. To define the biological role of iNOS further, we generated iNOS mutant mice. These are viable, fertile and without evident histopathological abnormalities. However, in contrast to wild-type and heterozygous mice, which are highly resistant to the protozoa parasite Leishmania major infection, mutant mice are uniformly susceptible. The infected mutant mice developed a significantly stronger Th1 type of immune response than the wild-type or heterozygous mice. The mutant mice showed reduced nonspecific inflammatory response to carrageenin, and were resistant to lipopolysaccharide-induced mortality.

Research paper thumbnail of Dual inhibitory and stimulatory activities in serum from SLE patients and lupus mice that regulate the proliferation of an IL-2-dependent T cell line

Lupus, 1995

In serum and plasma from SLE patients, we have detected elevated levels of factors which regulate... more In serum and plasma from SLE patients, we have detected elevated levels of factors which regulate proliferative responses of CTLL cells to IL-2. Serum samples containing these factors have dose-dependent dual inhibitory and stimulatory activities on the proliferation of this IL-2-dependent T lymphocyte cell line. At high concentrations, the serum factors inhibit the proliferative responses of CTLL cells to IL-2. At low concentrations, they synergise with IL-2 stimulating the growth of cells. Similar inhibitory activity, but with lower titre, was also found to be elevated in sera of some MRL/lpr mice, an animal model of SLE. Functional characterisation of the serum factors shows that: (1) the inhibitory activity cannot be neutralised by exogenous IL-2; (2) the stimulatory activity is not due to the presence of serum IL-2 but synergy of the factor with IL-2; (3) the factors bind directly to CTLL cells but they do not bind to protein A; and (4) the serum factors are not dialysable but heat labile. The possible pathological implications of the serum factors, particularly for the defective T cell functions in lupus disease, are discussed.

Research paper thumbnail of Modulation of autoimmune disease in the MRL-lpr/lpr mouse by IL-2 and TGF-β<SUB>1</SUB> gene therapy using attenuated Salmonella typhimurium as gene carrier

Lupus, 1999

We have investigated the effects of interleukin-2 (IL-2) and transforming growth factor-beta (TGF... more We have investigated the effects of interleukin-2 (IL-2) and transforming growth factor-beta (TGF-beta) gene therapy on the progress of autoimmune disease in MRL-lpr/lpr mice, a murine model of systemic lupus erythematosus (SLE). These mice have uncontrolled proliferation of T cells, an impaired response to T cell mitogen and produce autoantibodies against nuclear antigens, including DNA. Immune complexes formed by these autoantibodies are believed to cause glomerulonephritis and vasculitis in lupus mice and human SLE. Since there is an imbalance of cytokine production in both SLE patients and lupus mice, we examined the effects of cytokine gene therapy on the progression of autoimmune disease in MRL-lpr/lpr mice. The mice were treated orally with a non-pathogenic strain of Salmonella typhimurium bearing the aroA-aroD- mutations and carrying the murine genes encoding IL-2 and TGF-beta. The bacteria synthesise and slowly release the cytokines in vivo. Our results show that, contrary to expectation, TGF-beta gene therapy produced no improvement in pathology and generally had opposite effects to those of IL-2. IL-2 gene therapy restored the defective T cell proliferative response to mitogen and suppressed the autoantibody response, glomerulonephritis and growth of lymphoid tumours.

Research paper thumbnail of Functional Comparison of Cord and Adult Blood-Derived Dendritic Cells

Journal of Pediatric Hematology/Oncology, 2005

Research paper thumbnail of Aberrant dendritic cell differentiation initiated by the Mll-Een fusion gene does not require leukemic transformation

Journal of Leukocyte Biology, 2007

Dendritic cells (DCs), as specialized APCs, play a key role in the induction of anti-tumor immuni... more Dendritic cells (DCs), as specialized APCs, play a key role in the induction of anti-tumor immunity. They originate from bone marrow (BM) progenitors, which are frequently the targets of chromosomal translocations leading to development of leukemia. Aberrant DC differentiation and functions have been observed and are widely reported in patients with leukemia. It is not clear, however, whether such defects are a direct effect of a leukemic fusion gene or simply an outcome of the clinical disease. In this study, we demonstrate for the first time that knockin of the Mll-Een fusion gene can affect myeloid DC differentiation and functions directly, independent of the leukemic disease activities. We showed that the Mll-Een-expressing BM cells [enhanced green fluorescent protein؉ (EGFP ؉)] from leukemic and nonleukemic mice had similarly impaired DC differentiation capacities with functional abnormalities. In contrast, BM cells without Mll-Een expression (EGFP-) showed normal DC differentiation and functions. A reduction in the frequency of CD11c ؉ DCs was also observed within the EGFP ؉ population in spleen and lymph nodes, and these cells were dysfunctional. Taken together, our findings suggest that the Mll-Een fusion gene can affect myeloid DC differentiation directly and functions in a cell-autonomous manner, where fully leukemic transformation of the hematopoietic progenitors is not required exclusively. Therefore, the study provides evidence for a direct causal relationship between leukemic gene fusion and abnormal DC differentiation, possibly contributing to the development of leukemia.

Research paper thumbnail of A Proinflammatory Role of IL-18 in the Development of Spontaneous Autoimmune Disease

The Journal of Immunology, 2001

Research paper thumbnail of A Crucial Role for Dendritic Cell (DC) IL-10 in Inhibiting Successful DC-Based Immunotherapy: Superior Antitumor Immunity against Hepatocellular Carcinoma Evoked by DC Devoid of IL-10

The Journal of Immunology, 2007

The dendritic cell (DC)-based tumor immunotherapy has been a new promise of cure for cancer patie... more The dendritic cell (DC)-based tumor immunotherapy has been a new promise of cure for cancer patients, but animal studies and clinical trials have thus far only shown limited success, especially in treating established tumors. Certain immunosuppressive mechanisms triggered by tumor cells or the derivatives are believed to be a major obstacle. We studied the role of DC-derived IL-10 and its negative impact on vaccine efficacy in mouse models. Liver tumor cells were injected via the portal vein, giving rise to disseminated intrahepatic tumors, or s.c. to form solid but extrahepatic tumors. Bone marrow-derived DCs were generated from normal or IL-10-deficient mice and used as the vector to deliver tumor Ags. We demonstrate here that DCs devoid of IL-10, a potent immunosuppressive cytokine, are superior over conventional DCs in triggering antitumor immunity. The IL-10 ؊/؊ DCs were highly immunogenic, expressed enhanced levels of surface MHC class II molecules, and secreted increased amounts of Th1-related cytokines. By inducing tumor-specific killing and through the establishment of immunological memory, the vaccines delivered by IL-10 ؊/؊ DCs could evoke strong therapeutic and protective immunity against hepatocellular carcinoma in the mouse models. These findings will have great clinical impact once being translated into the treatment of malignant, and potentially infectious, diseases in humans.

Research paper thumbnail of The role of interleukin 12 and nitric oxide in the development of spontaneous autoimmune disease in MRLMP-lprlpr mice

Journal of Experimental Medicine, 1996

MRL/MP-lpr/lpr (MRL/lpr) mice develop a spontaneous autoimmune disease. Serum from these mice con... more MRL/MP-lpr/lpr (MRL/lpr) mice develop a spontaneous autoimmune disease. Serum from these mice contained significantly higher concentrations of nitrite/nitrate than serum from age-matched control MRL/MP-+/+ (MRL/+), BALB/c or CBA/6J mice. Spleen and peritoneal cells from MRL/lpr mice also produced significantly more nitric oxide (NO) than those from the control mice when cultured with interferon (IFN) gamma and lipopolysaccharide (LPS) in vitro. It is interesting to note that peritoneal cells from MRL/lpr mice also produced markedly higher concentrations of interleukin (IL) 12 than those from MRL/+ or BALB/c mice when cultured with same stimuli. It is striking that cells from MRL/lpr mice produced high concentrations of NO when cultured cells from MRL/+ or BALB/c mice. The enhanced NO synthesis induced by IFN-gamma/LPS was substantially inhibited by anti-IL-12 antibody. In addition, IL-12-induced NO production can also be markedly inhibited by anti-IFN-gamma antibody, but only weakly...

Research paper thumbnail of The Evolutionary Role of the IL-33/ST2 System in Host Immune Defence

Archivum Immunologiae et Therapiae Experimentalis, 2013

Interleukin (IL)-33 is a recently identified pleiotropic cytokine, which can orchestrate complex ... more Interleukin (IL)-33 is a recently identified pleiotropic cytokine, which can orchestrate complex innate and adaptive immune responses in immunity and disease. It has been characterized as a cytokine of the IL-1 family and affects a wide range of immune cells by signalling through its receptor ST2L. Accumulating evidence suggests a crucial role of IL-33/ST2 in inducing and modifying host immune responses against a variety of pathogens including parasites, bacteria, viruses and fungi as well as sterile insults of both endogenous and exogenous source. In this review, we endeavour to give a comprehensive overview of the current knowledge about the role of IL-33 and its receptor ST2 in host defence against infections.

Research paper thumbnail of Uptake of Antigens from the Intestine by Dendritic Cells

Annals of the New York Academy of Sciences, 2004

The intestinal immune system responds to ingested antigens in a variety of ways, ranging from tol... more The intestinal immune system responds to ingested antigens in a variety of ways, ranging from tolerance to full immunity. How T cells are instructed to make these differential responses is still unclear. Dendritic cells (DCs) sample enteric antigens in the lamina propria and Peyer&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s patches, and transport them within the patch or to mesenteric nodes where they are presented to lymphocytes. It is probable that DCs also transmit information that influences the outcome of T cell activation, but the nature of this information and the factors in the intestine that regulate DC behavior and properties are far from clear. We have developed a model in the rat that permits analysis of DCs actually in the process of migration from the intestine to mesenteric nodes. In this paper we will review those aspects of our research that relate to antigen uptake and discuss these in the context of other experimental systems.

Research paper thumbnail of Development of dendritic cell-based tumor vaccines with high efficacy by targeting the negative regulators of DC functions: Guiding the 'misguided

Invited speaker - ScientificTracks AbstractsThe DC-based therapeutic vaccine has been a theoretic... more Invited speaker - ScientificTracks AbstractsThe DC-based therapeutic vaccine has been a theoretically attractive approach being explored for cancer treatment during the last 2 decades. Its clinical application, however, has thus far been limited by the lack of achievable general efficacy and consistency. One of the major obstacles is believed to be the immunosuppressive tumor microenvironment these live DC cells are subjected to. To develop a novel DC-based tumor vaccine with high efficacy and stability, we have designed, tested and compared different ways of enhancing DC immunogenicity by functional conditioning of the cell vectors, targeting both the positive and negative arms of immune regulation. Findings from our studies indicate that the most effective way to enhance the vaccine efficacy is to block the negative regulators of DC functions. We showed that the vaccines delivered by DCs devoid or knock-down of IL-10, a potent immunosuppressive cytokine expressed by DC, were super...

Research paper thumbnail of Serum levels of IL-33 and soluble ST2 and their association with disease activity in systemic lupus erythematosus

Rheumatology, 2009

Objective. IL-33 has recently been found to be the specific ligand of ST2, an IL-1 receptor famil... more Objective. IL-33 has recently been found to be the specific ligand of ST2, an IL-1 receptor family member that is selectively expressed in Th2 cells and mediates Th2 response. This study aims to measure the serum levels of soluble ST2 (sST2) and IL-33 in patients with SLE and to examine their association with disease activity. Methods. Seventy SLE patients were evaluated for disease activity, determined by SLEDAI, levels of anti-dsDNA antibody, C3 and C4. Fifty-seven patients were evaluated longitudinally on a second occasion. IL-33 and sST2 were measured by sandwich ELISA in the 127 SLE serum samples and compared with 28 age-and sex-matched healthy controls. Results. Serum sST2 level was significantly higher in active SLE patients [0.51 (0.18) ng/ml] compared with inactive patients [0.42 (0.08) ng/ml] (P = 0.006) and normal controls [0.36 (0.13) ng/ml] (P < 0.001). sST2 level correlated significantly with SLEDAI, anti-dsDNA antibody and prednisolone dosage, and negatively with C3. Linear regression analysis showed that serum sST2 level was an independent predictive factor for modified SLEDAI, excluding anti-dsDNA and complement score after controlling for age, sex, glomerular filtration rate and prednisolone dosage (regression coefficient: 8.5; 95% CI 2.6, 14.3) (P = 0.005). Serum sST2 level was sensitive to change in disease activity longitudinally, with an effect size of 0.29. Elevated serum IL-33 was comparable in frequency (4.3 vs 7.1%; P = 0.62) and levels (P = 0.53) between SLE patients and controls. Conclusions. Elevated serum sST2 level in SLE patients was found to correlate with disease activity and was sensitive to change, suggesting a potential role as a surrogate marker of disease activity.

Research paper thumbnail of Mice lacking inducible nitric oxide synthase are not resistant to lipopolysaccharide-induced death

Proceedings of the National Academy of Sciences, 1995

Nitric oxide produced by cytokine-inducible nitric oxide synthase (iNOS) is thought to be importa... more Nitric oxide produced by cytokine-inducible nitric oxide synthase (iNOS) is thought to be important in the pathogenesis of septic shock. To further our understanding of the role of iNOS in normal biology and in a variety of inflammatory disorders, including septic shock, we have used gene targeting to generate a mouse strain that lacks iNOS. Mice lacking iNOS were indistinguishable from wild-type mice in appearance and histology. Upon treatment with lipopolysaccharide and interferon gamma, peritoneal macrophages from the mutant mice did not produce nitric oxide measured as nitrite in the culture medium. In addition, lysates of these cells did not contain iNOS protein by immunoblot analysis or iNOS enzyme activity. In a Northern analysis of total RNA, no iNOS transcript of the correct size was detected. No increases in serum nitrite plus nitrate levels were observed in homozygous mutant mice treated with a lethal dose of lipopolysaccharide, but the mutant mice exhibited no significan...

Research paper thumbnail of Production of nitric oxide in the synovial membrane of rheumatoid and osteoarthritis patients

Journal of Experimental Medicine, 1996

We have demonstrated spontaneous nitric oxide (NO) production by primary synovial cultures from r... more We have demonstrated spontaneous nitric oxide (NO) production by primary synovial cultures from rheumatoid (RA) and osteoarthritis patients. Increased NO production followed addition of staphylococcal enterotoxin B. Immunochemical double staining with specific anti-human inducible NO synthase (iNOS) and nonspecific esterase (NSE), or anti-CD68 (markers for tissue macrophages) showed that although many lining layer cells in RA synovium expressed iNOS, most (approximately 90%) were NSE- and CD68-, with only a minor population (approximately 10%) which were iNOS+, CD68+/NSE+. These data demonstrate the capacity for high output of NO by human synovial tissue and show that, although human macrophages can express high levels of iNOS, the majority of cells expressing iNOS are fibroblasts. We also report that synoviocytes, and macrophage cell lines, cultured with the NO donor, S-nitroso-acetyl penicillamine, produced high concentrations of tumor necrosis factor (TNF)-alpha. These results su...

Research paper thumbnail of Guidelines for the use of flow cytometry and cell sorting in immunological studies

European journal of immunology, Oct 1, 2017

Guidelines for the use of flow cytometry and cell sorting in immunological studies

Research paper thumbnail of Mice defective in Fas are highly susceptible to Leishmania major infection despite elevated IL-12 synthesis, strong Th1 responses, and enhanced nitric oxide production

MRL/MP-lpr/lpr (MRL/lpr) mice have a single mutation (lpr) of the fas apoptosis gene. The mutant ... more MRL/MP-lpr/lpr (MRL/lpr) mice have a single mutation (lpr) of the fas apoptosis gene. The mutant mice developed significantly smaller lesions than the wild-type mice at the earlier stage of infection with the intracellular protozoan parasite Leishmania major. However, while all the wild-type mice achieved complete lesion resolution, the disease in the mutant mice progressed inexorably. The mutant mice had more IL-12 and nitrite/nitrate in the serum than wild-type mice following infection. Lymphoid cells from infected MRL/lpr mice produced more IFN-gamma but less IL-4 and IL-5 than cells from MRL-+/+ mice. Peritoneal macrophages from the mutant mice also produced more IL-12 and NO after stimulation with LPS. Thus, Fas expression is essential for resistance against leishmaniasis, and Fas-mediated apoptosis may form an integral part of the Th1-mediated microbicidal function.

Research paper thumbnail of Mice defective in Fas are highly susceptible to Leishmania major infection despite elevated IL-12 synthesis, strong Th1 responses, and enhanced nitric oxide production

Journal of immunology (Baltimore, Md. : 1950), 1998

MRL/MP-lpr/lpr (MRL/lpr) mice have a single mutation (lpr) of the fas apoptosis gene. The mutant ... more MRL/MP-lpr/lpr (MRL/lpr) mice have a single mutation (lpr) of the fas apoptosis gene. The mutant mice developed significantly smaller lesions than the wild-type mice at the earlier stage of infection with the intracellular protozoan parasite Leishmania major. However, while all the wild-type mice achieved complete lesion resolution, the disease in the mutant mice progressed inexorably. The mutant mice had more IL-12 and nitrite/nitrate in the serum than wild-type mice following infection. Lymphoid cells from infected MRL/lpr mice produced more IFN-gamma but less IL-4 and IL-5 than cells from MRL-+/+ mice. Peritoneal macrophages from the mutant mice also produced more IL-12 and NO after stimulation with LPS. Thus, Fas expression is essential for resistance against leishmaniasis, and Fas-mediated apoptosis may form an integral part of the Th1-mediated microbicidal function.

Research paper thumbnail of Skin Allograft Rejection in Mice Lacking Inducible Nitric Oxide SYNTHASE1

Transplantation, 1997

During allograft rejection, up-regulation of cytokine-inducible nitric oxide synthase (iNOS) lead... more During allograft rejection, up-regulation of cytokine-inducible nitric oxide synthase (iNOS) leads to the production of large amounts of nitric oxide (NO). The net effect of NO on the alloimmune response is, however, difficult to predict because of its diverse biological effects, which include potentially opposing roles as an effector and immunoregulatory molecule. In this study, the role of iNOS on the in vitro and in vivo alloimmune response was defined using mutant mice that lack a functional iNOS gene. The ability of spleen cells obtained from iNOS-deficient mutants to proliferate and to produce cytokines in response to irradiated BALB/c stimulator cells was determined, and the rate at which iNOS-deficient mice were able to reject BALB/c skin allografts was observed. Spleen cells from homozygous iNOS-deficient (129xMF1)F1 mice, when compared with cells from heterozygous control mice, showed an increased in vitro proliferative response and produced substantially higher levels of interferon-gamma, and also more interleukin-2 and interleukin-12, in response to allogeneic stimulation. The kinetics of BALB/c skin graft rejection were comparable in heterozygous control animals and iNOS-deficient mice. Moreover, no net effect of iNOS on skin allograft rejection was apparent in mice treated with depleting monoclonal antibodies (mAb) to CD4 or CD8 T cells, either alone or in combination, or in mice treated with both anti-CD8 mAb and a neutralizing anti-tumor necrosis factor mAb. These results show that iNOS has an immunomodulatory effect on the in vitro alloimmune response but lack of iNOS has no net influence on the kinetics of murine skin allograft rejection in either unmodified recipients or recipients in which the early contribution of T-cell subsets and tumor necrosis factor-alpha to graft rejection has been abrogated.

Research paper thumbnail of An essential protective role of IL-10 in the immunological mechanism underlying resistance vs susceptibility to lupus induction by dendritic cells and dying cells

Rheumatology, 2011

Objective. To define the role of IL-10 in lupus pathogenesis, and to understand the immunological... more Objective. To define the role of IL-10 in lupus pathogenesis, and to understand the immunological mechanisms underlying resistance vs susceptibility to lupus disease induction by dendritic cells (DCs) and dying cells. Methods. Groups of IL-10-deficient and normal C57BL/6 mice were injected with syngenic DCs that had ingested necrotic cells prepared by either freezethaw cycle (DC/nec F/T) or heat shock (DC/nec H/S) procedures, or with DC or necrotic cells alone, or with PBS only. Disease development, including proteinuria and renal pathological changes, was monitored. Levels of autoantibodies against different lupusassociated nuclear antigens were measured by ELISAs, and IC deposition in the kidneys was confirmed by immunostaining. Results. No significant proteinuria was detected in the mice. However, striking renal pathological changes typical of IC-mediated GN were consistently observed in the DC/nec F/T-treated IL-10 À/À mice. These included glomerular hypercellularity and macrophage infiltration, renal IC deposition, circulating kidneyreactive autoantibodies and the presence of immunoglobulin G2 isotype-specific antibody complexes in the diseased kidneys. We demonstrated further that host-derived IL-10 was primarily responsible for protecting against the induction of pathogenic Th1 type of autoantibody responses in the mice. Conclusion. IL-10 protects against the induction of lupus-like renal end-organ damage by downregulating pathogenic Th1 responses.

Research paper thumbnail of The role of interleukin–15 in T–cell migration and activation in rheumatoid arthritis

Nature Medicine, 1996

Interleukin 15 (IL-15) is a novel cytokine with interleukin-2-like activity. It is also a potent ... more Interleukin 15 (IL-15) is a novel cytokine with interleukin-2-like activity. It is also a potent T-lymphocyte chemoattractant. Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by the presence of activated T lymphocytes, macrophages and synoviocytes in the synovial membrane. The mechanisms of T-cell activation in RA are currently unclear. We report the presence of high concentrations of IL-15 in rheumatoid arthritis (RA) synovial fluid and have demonstrated its expression in the synovial membrane lining layer by immunohistochemistry. RA synovial fluids were found to contain chemotactic activity, which was attributable in part to the presence of IL-15. Moreover, in a murine model, injection of recombinant IL-15 was found to induce a local tissue inflammatory infiltrate consisting predominantly of T lymphocytes. Synovial fluid T lymphocytes proliferate in response to IL-15, demonstrating that continued responsiveness to IL-15 is a feature of T cells after entry into the synovial compartment. These data suggest that IL-15 can recruit and activate T lymphocytes in the synovial membrane, thereby contributing to RA pathogenesis.

Research paper thumbnail of Altered immune responses in mice lacking inducible nitric oxide synthase

Nature, 1995

Nitric oxide (NO) is important in many biological functions. It is generated from L-arginine by t... more Nitric oxide (NO) is important in many biological functions. It is generated from L-arginine by the enzyme NO synthase (NOS). The cytokine-inducible NOS (iNOS) is activated by several immunological stimuli, leading to the production of large quantities of NO which can be cytotoxic. To define the biological role of iNOS further, we generated iNOS mutant mice. These are viable, fertile and without evident histopathological abnormalities. However, in contrast to wild-type and heterozygous mice, which are highly resistant to the protozoa parasite Leishmania major infection, mutant mice are uniformly susceptible. The infected mutant mice developed a significantly stronger Th1 type of immune response than the wild-type or heterozygous mice. The mutant mice showed reduced nonspecific inflammatory response to carrageenin, and were resistant to lipopolysaccharide-induced mortality.

Research paper thumbnail of Dual inhibitory and stimulatory activities in serum from SLE patients and lupus mice that regulate the proliferation of an IL-2-dependent T cell line

Lupus, 1995

In serum and plasma from SLE patients, we have detected elevated levels of factors which regulate... more In serum and plasma from SLE patients, we have detected elevated levels of factors which regulate proliferative responses of CTLL cells to IL-2. Serum samples containing these factors have dose-dependent dual inhibitory and stimulatory activities on the proliferation of this IL-2-dependent T lymphocyte cell line. At high concentrations, the serum factors inhibit the proliferative responses of CTLL cells to IL-2. At low concentrations, they synergise with IL-2 stimulating the growth of cells. Similar inhibitory activity, but with lower titre, was also found to be elevated in sera of some MRL/lpr mice, an animal model of SLE. Functional characterisation of the serum factors shows that: (1) the inhibitory activity cannot be neutralised by exogenous IL-2; (2) the stimulatory activity is not due to the presence of serum IL-2 but synergy of the factor with IL-2; (3) the factors bind directly to CTLL cells but they do not bind to protein A; and (4) the serum factors are not dialysable but heat labile. The possible pathological implications of the serum factors, particularly for the defective T cell functions in lupus disease, are discussed.

Research paper thumbnail of Modulation of autoimmune disease in the MRL-lpr/lpr mouse by IL-2 and TGF-β<SUB>1</SUB> gene therapy using attenuated Salmonella typhimurium as gene carrier

Lupus, 1999

We have investigated the effects of interleukin-2 (IL-2) and transforming growth factor-beta (TGF... more We have investigated the effects of interleukin-2 (IL-2) and transforming growth factor-beta (TGF-beta) gene therapy on the progress of autoimmune disease in MRL-lpr/lpr mice, a murine model of systemic lupus erythematosus (SLE). These mice have uncontrolled proliferation of T cells, an impaired response to T cell mitogen and produce autoantibodies against nuclear antigens, including DNA. Immune complexes formed by these autoantibodies are believed to cause glomerulonephritis and vasculitis in lupus mice and human SLE. Since there is an imbalance of cytokine production in both SLE patients and lupus mice, we examined the effects of cytokine gene therapy on the progression of autoimmune disease in MRL-lpr/lpr mice. The mice were treated orally with a non-pathogenic strain of Salmonella typhimurium bearing the aroA-aroD- mutations and carrying the murine genes encoding IL-2 and TGF-beta. The bacteria synthesise and slowly release the cytokines in vivo. Our results show that, contrary to expectation, TGF-beta gene therapy produced no improvement in pathology and generally had opposite effects to those of IL-2. IL-2 gene therapy restored the defective T cell proliferative response to mitogen and suppressed the autoantibody response, glomerulonephritis and growth of lymphoid tumours.

Research paper thumbnail of Functional Comparison of Cord and Adult Blood-Derived Dendritic Cells

Journal of Pediatric Hematology/Oncology, 2005

Research paper thumbnail of Aberrant dendritic cell differentiation initiated by the Mll-Een fusion gene does not require leukemic transformation

Journal of Leukocyte Biology, 2007

Dendritic cells (DCs), as specialized APCs, play a key role in the induction of anti-tumor immuni... more Dendritic cells (DCs), as specialized APCs, play a key role in the induction of anti-tumor immunity. They originate from bone marrow (BM) progenitors, which are frequently the targets of chromosomal translocations leading to development of leukemia. Aberrant DC differentiation and functions have been observed and are widely reported in patients with leukemia. It is not clear, however, whether such defects are a direct effect of a leukemic fusion gene or simply an outcome of the clinical disease. In this study, we demonstrate for the first time that knockin of the Mll-Een fusion gene can affect myeloid DC differentiation and functions directly, independent of the leukemic disease activities. We showed that the Mll-Een-expressing BM cells [enhanced green fluorescent protein؉ (EGFP ؉)] from leukemic and nonleukemic mice had similarly impaired DC differentiation capacities with functional abnormalities. In contrast, BM cells without Mll-Een expression (EGFP-) showed normal DC differentiation and functions. A reduction in the frequency of CD11c ؉ DCs was also observed within the EGFP ؉ population in spleen and lymph nodes, and these cells were dysfunctional. Taken together, our findings suggest that the Mll-Een fusion gene can affect myeloid DC differentiation directly and functions in a cell-autonomous manner, where fully leukemic transformation of the hematopoietic progenitors is not required exclusively. Therefore, the study provides evidence for a direct causal relationship between leukemic gene fusion and abnormal DC differentiation, possibly contributing to the development of leukemia.

Research paper thumbnail of A Proinflammatory Role of IL-18 in the Development of Spontaneous Autoimmune Disease

The Journal of Immunology, 2001

Research paper thumbnail of A Crucial Role for Dendritic Cell (DC) IL-10 in Inhibiting Successful DC-Based Immunotherapy: Superior Antitumor Immunity against Hepatocellular Carcinoma Evoked by DC Devoid of IL-10

The Journal of Immunology, 2007

The dendritic cell (DC)-based tumor immunotherapy has been a new promise of cure for cancer patie... more The dendritic cell (DC)-based tumor immunotherapy has been a new promise of cure for cancer patients, but animal studies and clinical trials have thus far only shown limited success, especially in treating established tumors. Certain immunosuppressive mechanisms triggered by tumor cells or the derivatives are believed to be a major obstacle. We studied the role of DC-derived IL-10 and its negative impact on vaccine efficacy in mouse models. Liver tumor cells were injected via the portal vein, giving rise to disseminated intrahepatic tumors, or s.c. to form solid but extrahepatic tumors. Bone marrow-derived DCs were generated from normal or IL-10-deficient mice and used as the vector to deliver tumor Ags. We demonstrate here that DCs devoid of IL-10, a potent immunosuppressive cytokine, are superior over conventional DCs in triggering antitumor immunity. The IL-10 ؊/؊ DCs were highly immunogenic, expressed enhanced levels of surface MHC class II molecules, and secreted increased amounts of Th1-related cytokines. By inducing tumor-specific killing and through the establishment of immunological memory, the vaccines delivered by IL-10 ؊/؊ DCs could evoke strong therapeutic and protective immunity against hepatocellular carcinoma in the mouse models. These findings will have great clinical impact once being translated into the treatment of malignant, and potentially infectious, diseases in humans.

Research paper thumbnail of The role of interleukin 12 and nitric oxide in the development of spontaneous autoimmune disease in MRLMP-lprlpr mice

Journal of Experimental Medicine, 1996

MRL/MP-lpr/lpr (MRL/lpr) mice develop a spontaneous autoimmune disease. Serum from these mice con... more MRL/MP-lpr/lpr (MRL/lpr) mice develop a spontaneous autoimmune disease. Serum from these mice contained significantly higher concentrations of nitrite/nitrate than serum from age-matched control MRL/MP-+/+ (MRL/+), BALB/c or CBA/6J mice. Spleen and peritoneal cells from MRL/lpr mice also produced significantly more nitric oxide (NO) than those from the control mice when cultured with interferon (IFN) gamma and lipopolysaccharide (LPS) in vitro. It is interesting to note that peritoneal cells from MRL/lpr mice also produced markedly higher concentrations of interleukin (IL) 12 than those from MRL/+ or BALB/c mice when cultured with same stimuli. It is striking that cells from MRL/lpr mice produced high concentrations of NO when cultured cells from MRL/+ or BALB/c mice. The enhanced NO synthesis induced by IFN-gamma/LPS was substantially inhibited by anti-IL-12 antibody. In addition, IL-12-induced NO production can also be markedly inhibited by anti-IFN-gamma antibody, but only weakly...