Hans Yssel - Academia.edu (original) (raw)
Papers by Hans Yssel
Journal of Immunological Methods, 1984
A serum-free lymphocyte culture medium is described in which serum is replaced by bovine serum al... more A serum-free lymphocyte culture medium is described in which serum is replaced by bovine serum albumin, transferrin, insulin, ethanolamine and a mixture of saturated and unsaturated fatty acids (linoleic acid, oleic acid and palmitic acid). In this serum-free medium proliferative and cytotoxic responses induced in mixed lymphocyte culture were comparable with those obtained in medium containing serum.
PLoS Pathogens, 2011
The ultimate stage of the transmission of Dengue Virus (DENV) to man is strongly dependent on cro... more The ultimate stage of the transmission of Dengue Virus (DENV) to man is strongly dependent on crosstalk between the virus and the immune system of its vector Aedes aegypti (Ae. aegypti). Infection of the mosquito's salivary glands by DENV is the final step prior to viral transmission. Therefore, in the present study, we have determined the modulatory effects of DENV infection on the immune response in this organ by carrying out a functional genomic analysis of uninfected salivary glands and salivary glands of female Ae. aegypti mosquitoes infected with DENV. We have shown that DENV infection of salivary glands strongly up-regulates the expression of genes that encode proteins involved in the vector's innate immune response, including the immune deficiency (IMD) and Toll signalling pathways, and that it induces the expression of the gene encoding a putative anti-bacterial, cecropin-like, peptide (AAEL000598). Both the chemically synthesized non-cleaved, signal peptide-containing gene product of AAEL000598, and the cleaved, mature form, were found to exert, in addition to antibacterial activity, anti-DENV and anti-Chikungunya viral activity. However, in contrast to the mature form, the immature cecropin peptide was far more effective against Chikungunya virus (CHIKV) and, furthermore, had strong anti-parasite activity as shown by its ability to kill Leishmania spp. Results from circular dichroism analysis showed that the immature form more readily adopts a helical conformation which would help it to cause membrane permeabilization, thus permitting its transfer across hydrophobic cell surfaces, which may explain the difference in the anti-pathogenic activity between the two forms. The present study underscores not only the importance of DENV-induced cecropin in the innate immune response of Ae. aegypti, but also emphasizes the broad-spectrum anti-pathogenic activity of the immature, signal peptidecontaining form of this peptide.
Journal of immunology (Baltimore, Md. : 1950), 1997
Allergen-specific Th2 cells accumulate at high frequencies in the skin of patients with atopic de... more Allergen-specific Th2 cells accumulate at high frequencies in the skin of patients with atopic dermatitis (AD), where they contribute to the induction and maintenance of the lesions that are characteristic for the disease. Attenuation of these lesions in response to successful therapy is associated with a reduction in IL-4-producing Th2 cells and the appearance of IFN-gamma-producing Th cells. In this study, we demonstrate that engagement of the signaling lymphocytic activation molecule (SLAM) by an agonistic mAb, during allergen-specific expansion of highly polarized Th2 cell populations derived from skin biopsies of AD patients, results in the generation of stable populations of IFN-gamma-producing cells. SLAM-mediated reversal of Th cell phenotype has important biologic consequences, because supernatants of these activated, allergen-specific Th cells fail to induce IgE synthesis by purified B cells costimulated by anti-CD40 mAbs. Thus, highly polarized, allergen-specific Th2 cell...
Journal of Virology, 2015
Zika virus (ZIKV) is an emerging arbovirus of the Flaviviridae family, which includes dengue, Wes... more Zika virus (ZIKV) is an emerging arbovirus of the Flaviviridae family, which includes dengue, West Nile, yellow fever, and Japanese encephalitis viruses, that causes a mosquito-borne disease transmitted by the Aedes genus, with recent outbreaks in the South Pacific. Here we examine the importance of human skin in the entry of ZIKV and its contribution to the induction of antiviral immune responses. We show that human dermal fibroblasts, epidermal keratinocytes, and immature dendritic cells are permissive to the most recent ZIKV isolate, responsible for the epidemic in French Polynesia. Several entry and/or adhesion factors, including DC-SIGN, AXL, Tyro3, and, to a lesser extent, TIM-1, permitted ZIKV entry, with a major role for the TAM receptor AXL. The ZIKV permissiveness of human skin fibroblasts was confirmed by the use of a neutralizing antibody and specific RNA silencing. ZIKV induced the transcription of Toll-like receptor 3 (TLR3), RIG-I, and MDA5, as well as several interferonstimulated genes, including OAS2, ISG15, and MX1, characterized by strongly enhanced beta interferon gene expression. ZIKV was found to be sensitive to the antiviral effects of both type I and type II interferons. Finally, infection of skin fibroblasts resulted in the formation of autophagosomes, whose presence was associated with enhanced viral replication, as shown by the use of Torin 1, a chemical inducer of autophagy, and the specific autophagy inhibitor 3-methyladenine. The results presented herein permit us to gain further insight into the biology of ZIKV and to devise strategies aiming to interfere with the pathology caused by this emerging flavivirus.
Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases, Jan 3, 2015
Arboviruses represent an emerging threat to human. They are transmitted to vertebrates by the bit... more Arboviruses represent an emerging threat to human. They are transmitted to vertebrates by the bite of infected arthropods. Early transmission to vertebrates is initiated by skin puncture and deposition of virus in this organ. However, events at the bite site remain largely unknown. Here, we report that Chikungunya virus (CHIKV) and West Nile virus (WNV), despite belonging to distinct viral families, elicit a common antiviral signature in primary human dermal fibroblasts, attesting for the up regulation of interferon signalling pathways and leading to an increased expression of IFN-β, interleukins and chemokines. Remarkably, CHIKV and WNV enhance IL-1β expression and induce maturation of caspase-1, indicating the capacity of these pathogens to elicit activation of the inflammasome program in resident skin cells. CHIKV and WNV also induce the expression of the inflammasome sensor AIM2 in dermal fibroblasts, whereas inhibition of caspase-1 and AIM2 with siRNA interferes with both CHIKV...
Research in immunology, 1991
Current Protocols in Immunology, 2001
This unit describes protocols for the generation of human (allo-) antigen-specific T cell lines, ... more This unit describes protocols for the generation of human (allo-) antigen-specific T cell lines, and T lymphocyte subpopulations with distinct cytokine production profiles from purified peripheral or cord blood CD4+ T cells, respectively. Methods for the cloning and maintenance of these cell lines are given, as well as a protocol for freeze/thaw procedures.
PLoS ONE, 2014
Multidrug resistance, which is acquired by both Gram-positive and Gram-negative bacteria, causes ... more Multidrug resistance, which is acquired by both Gram-positive and Gram-negative bacteria, causes infections that are associated with significant morbidity and mortality in many clinical settings around the world. Because of the rapidly increasing incidence of pathogens that have become resistant to all or nearly all available antibiotics, there is a need for a new generation of antimicrobials with a broad therapeutic range for specific applications against infections. Aedesin is a cecropin-like anti-microbial peptide that was recently isolated from dengue virus-infected salivary glands of the Aedes aegypti mosquito. In the present study, we have refined the analysis of its structural characteristics and have determined its antimicrobial effects against a large panel of multidrug resistant bacterial strains, directly isolated from infected patients. Based the results from nuclear magnetic resonance spectroscopy analysis, Aedesin has a helix-bend-helix structure typical for a member of the family of a-helix anti-microbial peptides. Aedesin efficiently killed Gram-negative bacterial strains that display the most worrisome resistance mechanisms encountered in the clinic, including resistance to carbapenems, aminoglycosides, cephalosporins, 4 th generation fluoroquinolones, folate inhibitors and monobactams. In contrast, Grampositive strains were insensitive to the lytic effects of the peptide. The anti-bacterial activity of Aedesin was found to be saltresistant, indicating that it is active under physiological conditions encountered in body fluids characterized by ionic salt concentrations. In conclusion, because of its strong lytic activity against multidrug resistant Gram-negative bacterial strains displaying all types of clinically relevant resistance mechanisms known today, Aedesin might be an interesting candidate for the development of alternative treatment for infections caused by these types of bacteria.
Cytokine, 1995
In this study we demonstrate that the cytokines IL-4 and IL-13, but not IL-10, can induce osteobl... more In this study we demonstrate that the cytokines IL-4 and IL-13, but not IL-10, can induce osteoblast chemotaxis. Recombinant IL-4 (rIL-4) and rIL-13 mediated cell migration was observed using a modified multi-well Boyden chamber system. Maximum chemotaxis was observed at concentrations of 100 ng/ml of both rIL-4 and rIL-13 with a chemotactic index of 2.0 ± 0.1 and 2.3 ±
BMC Immunology, 2002
Background: Human resistance to re-infection with S. mansoni is correlated with high levels of an... more Background: Human resistance to re-infection with S. mansoni is correlated with high levels of anti-soluble adult worm antigens (SWAP) IgE. Although it has been shown that IL-4 and IL-5 are crucial in establishing IgE responses in vitro, the active in vivo production of these cytokines by T cells, and the degree of polarization of Th2 vs. Th0 in human schistosomiasis is not known. To address this question, we determined the frequency of IL-4 and IFN-γ or IL-5 and IL-2 producing lymphocytes from schistosomiasis patients with high or low levels of IgE anti-SWAP.
Gut, 2014
Under both physiological and pathological conditions, bone volume is determined by the rate of bo... more Under both physiological and pathological conditions, bone volume is determined by the rate of bone formation by osteoblasts and bone resorption by osteoclasts. Excessive bone loss is a common complication of human IBD whose mechanisms are not yet completely understood. Despite the role of activated CD4(+) T cells in inflammatory bone loss, the nature of the T cell subsets involved in this process in vivo remains unknown. The aim of the present study was to identify the CD4(+) T cell subsets involved in the process of osteoclastogenesis in vivo, as well as their mechanism of action. CD4(+) T cells were studied in IL10-/- mice and Rag1-/- mice adoptively transferred with naive CD4(+)CD45RB(high) T cells, representing two well-characterised animal models of IBD and in patients with Crohn's disease. They were phenotypically and functionally characterised by flow cytometric and gene expression analysis, as well as in in vitro cocultures with osteoclast precursors. In mice, we identified bone marrow (BM) CD4(+) T cells producing interleukin (IL)-17 and tumour necrosis factor (TNF)-α as an osteoclastogenic T cell subset referred to as Th17 TNF-α(+) cells. During chronic inflammation, these cells migrate to the BM where they survive in an IL-7-dependent manner and where they promote the recruitment of inflammatory monocytes, the main osteoclast progenitors. A population equivalent to the Th17 TNF-α(+) cells was also detected in patients with Crohn's disease. Our results highlight the osteoclastogenic function of the Th17 TNF-α(+) cells that contribute to bone loss in vivo in IBD.
Proceedings of the National Academy of Sciences, 1987
A subset of human T cells has recently been described. These cells express the CD3 complex but th... more A subset of human T cells has recently been described. These cells express the CD3 complex but they do not carry the classical T-cell receptor (TCR)-a/-p heterodimer on their surface (WT31-CD3+). Instead, they express a TCR-y chain associated with another type of polypeptide termed TCR-6. We report here that a T-cell clone with natural killer (NK)-like activity, WM-14, had a disulfide bridged TCR-y homodimer associated with CD3 on its surface. The TCR-y chains of WM-14 cells were present in three different glycosylation forms of 43, 40, and 38 kDa, but they appeared to contain the same polypeptide backbone. Since cytotoxicity by WM-14 could be inhibited by anti-CD3 antibodies, we concluded that the TCR-y-CD3 complex was involved in the NK-like unrestricted killer activity. Although normal CD3-y, CD3-6, and CD3-e chains were present in this clone, the association with the TCR-y homodimer may be the cause of a complete processing of the N-linked oligosaccharides attached to the CD3-6 chain.
Proceedings of the National Academy of Sciences, 1989
A cDNA clone encoding a human receptor for the Fc portion of IgG (FcyR), FcyRIll or CD16, was iso... more A cDNA clone encoding a human receptor for the Fc portion of IgG (FcyR), FcyRIll or CD16, was isolated from a human leukocyte library by a transient expressionimmunoselection procedure. This cDNA (pGP5) encodes a 46-kDa phosphatidylinositol-linked cell surface protein with CD16 determinants and affinity for human IgG. The deduced protein sequence is most homologous to the murine receptor
PLoS Pathogens, 2011
The ultimate stage of the transmission of Dengue Virus (DENV) to man is strongly dependent on cro... more The ultimate stage of the transmission of Dengue Virus (DENV) to man is strongly dependent on crosstalk between the virus and the immune system of its vector Aedes aegypti (Ae. aegypti). Infection of the mosquito's salivary glands by DENV is the final step prior to viral transmission. Therefore, in the present study, we have determined the modulatory effects of DENV infection on the immune response in this organ by carrying out a functional genomic analysis of uninfected salivary glands and salivary glands of female Ae. aegypti mosquitoes infected with DENV. We have shown that DENV infection of salivary glands strongly up-regulates the expression of genes that encode proteins involved in the vector's innate immune response, including the immune deficiency (IMD) and Toll signalling pathways, and that it induces the expression of the gene encoding a putative anti-bacterial, cecropin-like, peptide (AAEL000598). Both the chemically synthesized non-cleaved, signal peptide-containing gene product of AAEL000598, and the cleaved, mature form, were found to exert, in addition to antibacterial activity, anti-DENV and anti-Chikungunya viral activity. However, in contrast to the mature form, the immature cecropin peptide was far more effective against Chikungunya virus (CHIKV) and, furthermore, had strong anti-parasite activity as shown by its ability to kill Leishmania spp. Results from circular dichroism analysis showed that the immature form more readily adopts a helical conformation which would help it to cause membrane permeabilization, thus permitting its transfer across hydrophobic cell surfaces, which may explain the difference in the anti-pathogenic activity between the two forms. The present study underscores not only the importance of DENV-induced cecropin in the innate immune response of Ae. aegypti, but also emphasizes the broad-spectrum anti-pathogenic activity of the immature, signal peptidecontaining form of this peptide.
International Immunology, 1990
Cloned T lymphocytes reactive with Borrelia burgdorferi proteins were isolated from a patient wit... more Cloned T lymphocytes reactive with Borrelia burgdorferi proteins were isolated from a patient with chronic Lyme arthritis. All of the T cell clones which proliferated in response to Borrelia proteins were CD3 + CD4 + CD8 - TCR alpha beta + and HLA-DR restricted. One T cell clone (GN30) exhibited HLA-DR-restricted cytotoxic activity against antigen-presenting cells pulsed with Borrelia antigen. In response to Borrelia antigen, the T cell clones produced TNF-alpha, INF-gamma, and GM-CSF. There are at least three distinct spirochetal proteins recognized by the four T cell clones analyzed. Purified Borrelia proteins triggered the HLA-DR-restricted proliferative and cytotoxic responses, as well as lymphokine secretion by two of the T cell clones. The spirochetal protein which triggered the HLA-DR-restricted proliferative and cytotoxic activities of the T cell clone (GN30) isolated from synovial fluid is the 41 kd flagellar protein.
The Journal of Immunology, 2007
Journal of Immunological Methods, 2005
In the process of metastasis, malignant cells are released from the primary tumor and migrate to ... more In the process of metastasis, malignant cells are released from the primary tumor and migrate to specific organs via the lymphatic and blood circulation systems. These circulating tumor cells have been characterized by immunochemistry, the reverse transcription-polymerase chain reaction, and flow cytometry. Using the MCF-7 breast cancer cell line, we have developed a two-color ELISPOT assay to detect cells secreting cathepsin D protease and MUC1 glycoprotein, markers associated with the risk of metastases in breast cancer. The threshold of detection of this ELISPOT assay was one cathepsin Dor MUC1-secreting MCF7 cell per 5 ml of control blood. In 16 patients with breast carcinoma metastases, 1 to 1940 cathepsin D-or MUC1-secreting cells per 2 Â 10 7 PBMC were enumerated, whereas none were found in 11 controls. Moreover, in six patients 6-60% of MUC1-secreting cells also expressed the CXCR4 chemokine receptor, which is involved in the homing of metastatic breast cancer cells. The ELISPOT assay described here allowed us to enumerate cathepsin D-and/or MUC1-secreting cells in the MCF-7 cell line and in the peripheral blood of patients with disseminated breast cancer. The combination of the 0022-1759/$ -see front matter D ELISPOT assay and CXCR4-positive cell sorting identified subsets of MUC1-secreting cells in the peripheral blood of these patients. D
Journal of Immunological Methods, 2003
Various subpopulations of T lymphocytes-i.e. Type 1, Type 2, Tr1 T cells-play a major role in the... more Various subpopulations of T lymphocytes-i.e. Type 1, Type 2, Tr1 T cells-play a major role in the homeostasis of the immune system and in the pathogenesis of many inflammatory and auto-immune diseases. At present, in the absence of specific surface markers, these T cells can only be reliably distinguished on the basis of their cytokine production profile. The Elispot assay detects cytokine-producing cells, but in most cases can detect only one secreted cytokine, which represents a major limitation of this technique.
Journal of Immunological Methods, 1984
A serum-free lymphocyte culture medium is described in which serum is replaced by bovine serum al... more A serum-free lymphocyte culture medium is described in which serum is replaced by bovine serum albumin, transferrin, insulin, ethanolamine and a mixture of saturated and unsaturated fatty acids (linoleic acid, oleic acid and palmitic acid). In this serum-free medium proliferative and cytotoxic responses induced in mixed lymphocyte culture were comparable with those obtained in medium containing serum.
Journal of Immunological Methods, 1984
A serum-free lymphocyte culture medium is described in which serum is replaced by bovine serum al... more A serum-free lymphocyte culture medium is described in which serum is replaced by bovine serum albumin, transferrin, insulin, ethanolamine and a mixture of saturated and unsaturated fatty acids (linoleic acid, oleic acid and palmitic acid). In this serum-free medium proliferative and cytotoxic responses induced in mixed lymphocyte culture were comparable with those obtained in medium containing serum.
PLoS Pathogens, 2011
The ultimate stage of the transmission of Dengue Virus (DENV) to man is strongly dependent on cro... more The ultimate stage of the transmission of Dengue Virus (DENV) to man is strongly dependent on crosstalk between the virus and the immune system of its vector Aedes aegypti (Ae. aegypti). Infection of the mosquito's salivary glands by DENV is the final step prior to viral transmission. Therefore, in the present study, we have determined the modulatory effects of DENV infection on the immune response in this organ by carrying out a functional genomic analysis of uninfected salivary glands and salivary glands of female Ae. aegypti mosquitoes infected with DENV. We have shown that DENV infection of salivary glands strongly up-regulates the expression of genes that encode proteins involved in the vector's innate immune response, including the immune deficiency (IMD) and Toll signalling pathways, and that it induces the expression of the gene encoding a putative anti-bacterial, cecropin-like, peptide (AAEL000598). Both the chemically synthesized non-cleaved, signal peptide-containing gene product of AAEL000598, and the cleaved, mature form, were found to exert, in addition to antibacterial activity, anti-DENV and anti-Chikungunya viral activity. However, in contrast to the mature form, the immature cecropin peptide was far more effective against Chikungunya virus (CHIKV) and, furthermore, had strong anti-parasite activity as shown by its ability to kill Leishmania spp. Results from circular dichroism analysis showed that the immature form more readily adopts a helical conformation which would help it to cause membrane permeabilization, thus permitting its transfer across hydrophobic cell surfaces, which may explain the difference in the anti-pathogenic activity between the two forms. The present study underscores not only the importance of DENV-induced cecropin in the innate immune response of Ae. aegypti, but also emphasizes the broad-spectrum anti-pathogenic activity of the immature, signal peptidecontaining form of this peptide.
Journal of immunology (Baltimore, Md. : 1950), 1997
Allergen-specific Th2 cells accumulate at high frequencies in the skin of patients with atopic de... more Allergen-specific Th2 cells accumulate at high frequencies in the skin of patients with atopic dermatitis (AD), where they contribute to the induction and maintenance of the lesions that are characteristic for the disease. Attenuation of these lesions in response to successful therapy is associated with a reduction in IL-4-producing Th2 cells and the appearance of IFN-gamma-producing Th cells. In this study, we demonstrate that engagement of the signaling lymphocytic activation molecule (SLAM) by an agonistic mAb, during allergen-specific expansion of highly polarized Th2 cell populations derived from skin biopsies of AD patients, results in the generation of stable populations of IFN-gamma-producing cells. SLAM-mediated reversal of Th cell phenotype has important biologic consequences, because supernatants of these activated, allergen-specific Th cells fail to induce IgE synthesis by purified B cells costimulated by anti-CD40 mAbs. Thus, highly polarized, allergen-specific Th2 cell...
Journal of Virology, 2015
Zika virus (ZIKV) is an emerging arbovirus of the Flaviviridae family, which includes dengue, Wes... more Zika virus (ZIKV) is an emerging arbovirus of the Flaviviridae family, which includes dengue, West Nile, yellow fever, and Japanese encephalitis viruses, that causes a mosquito-borne disease transmitted by the Aedes genus, with recent outbreaks in the South Pacific. Here we examine the importance of human skin in the entry of ZIKV and its contribution to the induction of antiviral immune responses. We show that human dermal fibroblasts, epidermal keratinocytes, and immature dendritic cells are permissive to the most recent ZIKV isolate, responsible for the epidemic in French Polynesia. Several entry and/or adhesion factors, including DC-SIGN, AXL, Tyro3, and, to a lesser extent, TIM-1, permitted ZIKV entry, with a major role for the TAM receptor AXL. The ZIKV permissiveness of human skin fibroblasts was confirmed by the use of a neutralizing antibody and specific RNA silencing. ZIKV induced the transcription of Toll-like receptor 3 (TLR3), RIG-I, and MDA5, as well as several interferonstimulated genes, including OAS2, ISG15, and MX1, characterized by strongly enhanced beta interferon gene expression. ZIKV was found to be sensitive to the antiviral effects of both type I and type II interferons. Finally, infection of skin fibroblasts resulted in the formation of autophagosomes, whose presence was associated with enhanced viral replication, as shown by the use of Torin 1, a chemical inducer of autophagy, and the specific autophagy inhibitor 3-methyladenine. The results presented herein permit us to gain further insight into the biology of ZIKV and to devise strategies aiming to interfere with the pathology caused by this emerging flavivirus.
Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases, Jan 3, 2015
Arboviruses represent an emerging threat to human. They are transmitted to vertebrates by the bit... more Arboviruses represent an emerging threat to human. They are transmitted to vertebrates by the bite of infected arthropods. Early transmission to vertebrates is initiated by skin puncture and deposition of virus in this organ. However, events at the bite site remain largely unknown. Here, we report that Chikungunya virus (CHIKV) and West Nile virus (WNV), despite belonging to distinct viral families, elicit a common antiviral signature in primary human dermal fibroblasts, attesting for the up regulation of interferon signalling pathways and leading to an increased expression of IFN-β, interleukins and chemokines. Remarkably, CHIKV and WNV enhance IL-1β expression and induce maturation of caspase-1, indicating the capacity of these pathogens to elicit activation of the inflammasome program in resident skin cells. CHIKV and WNV also induce the expression of the inflammasome sensor AIM2 in dermal fibroblasts, whereas inhibition of caspase-1 and AIM2 with siRNA interferes with both CHIKV...
Research in immunology, 1991
Current Protocols in Immunology, 2001
This unit describes protocols for the generation of human (allo-) antigen-specific T cell lines, ... more This unit describes protocols for the generation of human (allo-) antigen-specific T cell lines, and T lymphocyte subpopulations with distinct cytokine production profiles from purified peripheral or cord blood CD4+ T cells, respectively. Methods for the cloning and maintenance of these cell lines are given, as well as a protocol for freeze/thaw procedures.
PLoS ONE, 2014
Multidrug resistance, which is acquired by both Gram-positive and Gram-negative bacteria, causes ... more Multidrug resistance, which is acquired by both Gram-positive and Gram-negative bacteria, causes infections that are associated with significant morbidity and mortality in many clinical settings around the world. Because of the rapidly increasing incidence of pathogens that have become resistant to all or nearly all available antibiotics, there is a need for a new generation of antimicrobials with a broad therapeutic range for specific applications against infections. Aedesin is a cecropin-like anti-microbial peptide that was recently isolated from dengue virus-infected salivary glands of the Aedes aegypti mosquito. In the present study, we have refined the analysis of its structural characteristics and have determined its antimicrobial effects against a large panel of multidrug resistant bacterial strains, directly isolated from infected patients. Based the results from nuclear magnetic resonance spectroscopy analysis, Aedesin has a helix-bend-helix structure typical for a member of the family of a-helix anti-microbial peptides. Aedesin efficiently killed Gram-negative bacterial strains that display the most worrisome resistance mechanisms encountered in the clinic, including resistance to carbapenems, aminoglycosides, cephalosporins, 4 th generation fluoroquinolones, folate inhibitors and monobactams. In contrast, Grampositive strains were insensitive to the lytic effects of the peptide. The anti-bacterial activity of Aedesin was found to be saltresistant, indicating that it is active under physiological conditions encountered in body fluids characterized by ionic salt concentrations. In conclusion, because of its strong lytic activity against multidrug resistant Gram-negative bacterial strains displaying all types of clinically relevant resistance mechanisms known today, Aedesin might be an interesting candidate for the development of alternative treatment for infections caused by these types of bacteria.
Cytokine, 1995
In this study we demonstrate that the cytokines IL-4 and IL-13, but not IL-10, can induce osteobl... more In this study we demonstrate that the cytokines IL-4 and IL-13, but not IL-10, can induce osteoblast chemotaxis. Recombinant IL-4 (rIL-4) and rIL-13 mediated cell migration was observed using a modified multi-well Boyden chamber system. Maximum chemotaxis was observed at concentrations of 100 ng/ml of both rIL-4 and rIL-13 with a chemotactic index of 2.0 ± 0.1 and 2.3 ±
BMC Immunology, 2002
Background: Human resistance to re-infection with S. mansoni is correlated with high levels of an... more Background: Human resistance to re-infection with S. mansoni is correlated with high levels of anti-soluble adult worm antigens (SWAP) IgE. Although it has been shown that IL-4 and IL-5 are crucial in establishing IgE responses in vitro, the active in vivo production of these cytokines by T cells, and the degree of polarization of Th2 vs. Th0 in human schistosomiasis is not known. To address this question, we determined the frequency of IL-4 and IFN-γ or IL-5 and IL-2 producing lymphocytes from schistosomiasis patients with high or low levels of IgE anti-SWAP.
Gut, 2014
Under both physiological and pathological conditions, bone volume is determined by the rate of bo... more Under both physiological and pathological conditions, bone volume is determined by the rate of bone formation by osteoblasts and bone resorption by osteoclasts. Excessive bone loss is a common complication of human IBD whose mechanisms are not yet completely understood. Despite the role of activated CD4(+) T cells in inflammatory bone loss, the nature of the T cell subsets involved in this process in vivo remains unknown. The aim of the present study was to identify the CD4(+) T cell subsets involved in the process of osteoclastogenesis in vivo, as well as their mechanism of action. CD4(+) T cells were studied in IL10-/- mice and Rag1-/- mice adoptively transferred with naive CD4(+)CD45RB(high) T cells, representing two well-characterised animal models of IBD and in patients with Crohn's disease. They were phenotypically and functionally characterised by flow cytometric and gene expression analysis, as well as in in vitro cocultures with osteoclast precursors. In mice, we identified bone marrow (BM) CD4(+) T cells producing interleukin (IL)-17 and tumour necrosis factor (TNF)-α as an osteoclastogenic T cell subset referred to as Th17 TNF-α(+) cells. During chronic inflammation, these cells migrate to the BM where they survive in an IL-7-dependent manner and where they promote the recruitment of inflammatory monocytes, the main osteoclast progenitors. A population equivalent to the Th17 TNF-α(+) cells was also detected in patients with Crohn's disease. Our results highlight the osteoclastogenic function of the Th17 TNF-α(+) cells that contribute to bone loss in vivo in IBD.
Proceedings of the National Academy of Sciences, 1987
A subset of human T cells has recently been described. These cells express the CD3 complex but th... more A subset of human T cells has recently been described. These cells express the CD3 complex but they do not carry the classical T-cell receptor (TCR)-a/-p heterodimer on their surface (WT31-CD3+). Instead, they express a TCR-y chain associated with another type of polypeptide termed TCR-6. We report here that a T-cell clone with natural killer (NK)-like activity, WM-14, had a disulfide bridged TCR-y homodimer associated with CD3 on its surface. The TCR-y chains of WM-14 cells were present in three different glycosylation forms of 43, 40, and 38 kDa, but they appeared to contain the same polypeptide backbone. Since cytotoxicity by WM-14 could be inhibited by anti-CD3 antibodies, we concluded that the TCR-y-CD3 complex was involved in the NK-like unrestricted killer activity. Although normal CD3-y, CD3-6, and CD3-e chains were present in this clone, the association with the TCR-y homodimer may be the cause of a complete processing of the N-linked oligosaccharides attached to the CD3-6 chain.
Proceedings of the National Academy of Sciences, 1989
A cDNA clone encoding a human receptor for the Fc portion of IgG (FcyR), FcyRIll or CD16, was iso... more A cDNA clone encoding a human receptor for the Fc portion of IgG (FcyR), FcyRIll or CD16, was isolated from a human leukocyte library by a transient expressionimmunoselection procedure. This cDNA (pGP5) encodes a 46-kDa phosphatidylinositol-linked cell surface protein with CD16 determinants and affinity for human IgG. The deduced protein sequence is most homologous to the murine receptor
PLoS Pathogens, 2011
The ultimate stage of the transmission of Dengue Virus (DENV) to man is strongly dependent on cro... more The ultimate stage of the transmission of Dengue Virus (DENV) to man is strongly dependent on crosstalk between the virus and the immune system of its vector Aedes aegypti (Ae. aegypti). Infection of the mosquito's salivary glands by DENV is the final step prior to viral transmission. Therefore, in the present study, we have determined the modulatory effects of DENV infection on the immune response in this organ by carrying out a functional genomic analysis of uninfected salivary glands and salivary glands of female Ae. aegypti mosquitoes infected with DENV. We have shown that DENV infection of salivary glands strongly up-regulates the expression of genes that encode proteins involved in the vector's innate immune response, including the immune deficiency (IMD) and Toll signalling pathways, and that it induces the expression of the gene encoding a putative anti-bacterial, cecropin-like, peptide (AAEL000598). Both the chemically synthesized non-cleaved, signal peptide-containing gene product of AAEL000598, and the cleaved, mature form, were found to exert, in addition to antibacterial activity, anti-DENV and anti-Chikungunya viral activity. However, in contrast to the mature form, the immature cecropin peptide was far more effective against Chikungunya virus (CHIKV) and, furthermore, had strong anti-parasite activity as shown by its ability to kill Leishmania spp. Results from circular dichroism analysis showed that the immature form more readily adopts a helical conformation which would help it to cause membrane permeabilization, thus permitting its transfer across hydrophobic cell surfaces, which may explain the difference in the anti-pathogenic activity between the two forms. The present study underscores not only the importance of DENV-induced cecropin in the innate immune response of Ae. aegypti, but also emphasizes the broad-spectrum anti-pathogenic activity of the immature, signal peptidecontaining form of this peptide.
International Immunology, 1990
Cloned T lymphocytes reactive with Borrelia burgdorferi proteins were isolated from a patient wit... more Cloned T lymphocytes reactive with Borrelia burgdorferi proteins were isolated from a patient with chronic Lyme arthritis. All of the T cell clones which proliferated in response to Borrelia proteins were CD3 + CD4 + CD8 - TCR alpha beta + and HLA-DR restricted. One T cell clone (GN30) exhibited HLA-DR-restricted cytotoxic activity against antigen-presenting cells pulsed with Borrelia antigen. In response to Borrelia antigen, the T cell clones produced TNF-alpha, INF-gamma, and GM-CSF. There are at least three distinct spirochetal proteins recognized by the four T cell clones analyzed. Purified Borrelia proteins triggered the HLA-DR-restricted proliferative and cytotoxic responses, as well as lymphokine secretion by two of the T cell clones. The spirochetal protein which triggered the HLA-DR-restricted proliferative and cytotoxic activities of the T cell clone (GN30) isolated from synovial fluid is the 41 kd flagellar protein.
The Journal of Immunology, 2007
Journal of Immunological Methods, 2005
In the process of metastasis, malignant cells are released from the primary tumor and migrate to ... more In the process of metastasis, malignant cells are released from the primary tumor and migrate to specific organs via the lymphatic and blood circulation systems. These circulating tumor cells have been characterized by immunochemistry, the reverse transcription-polymerase chain reaction, and flow cytometry. Using the MCF-7 breast cancer cell line, we have developed a two-color ELISPOT assay to detect cells secreting cathepsin D protease and MUC1 glycoprotein, markers associated with the risk of metastases in breast cancer. The threshold of detection of this ELISPOT assay was one cathepsin Dor MUC1-secreting MCF7 cell per 5 ml of control blood. In 16 patients with breast carcinoma metastases, 1 to 1940 cathepsin D-or MUC1-secreting cells per 2 Â 10 7 PBMC were enumerated, whereas none were found in 11 controls. Moreover, in six patients 6-60% of MUC1-secreting cells also expressed the CXCR4 chemokine receptor, which is involved in the homing of metastatic breast cancer cells. The ELISPOT assay described here allowed us to enumerate cathepsin D-and/or MUC1-secreting cells in the MCF-7 cell line and in the peripheral blood of patients with disseminated breast cancer. The combination of the 0022-1759/$ -see front matter D ELISPOT assay and CXCR4-positive cell sorting identified subsets of MUC1-secreting cells in the peripheral blood of these patients. D
Journal of Immunological Methods, 2003
Various subpopulations of T lymphocytes-i.e. Type 1, Type 2, Tr1 T cells-play a major role in the... more Various subpopulations of T lymphocytes-i.e. Type 1, Type 2, Tr1 T cells-play a major role in the homeostasis of the immune system and in the pathogenesis of many inflammatory and auto-immune diseases. At present, in the absence of specific surface markers, these T cells can only be reliably distinguished on the basis of their cytokine production profile. The Elispot assay detects cytokine-producing cells, but in most cases can detect only one secreted cytokine, which represents a major limitation of this technique.
Journal of Immunological Methods, 1984
A serum-free lymphocyte culture medium is described in which serum is replaced by bovine serum al... more A serum-free lymphocyte culture medium is described in which serum is replaced by bovine serum albumin, transferrin, insulin, ethanolamine and a mixture of saturated and unsaturated fatty acids (linoleic acid, oleic acid and palmitic acid). In this serum-free medium proliferative and cytotoxic responses induced in mixed lymphocyte culture were comparable with those obtained in medium containing serum.