Robbie Mailliard - Academia.edu (original) (raw)
Papers by Robbie Mailliard
Journal of Vascular Surgery, Oct 1, 2021
Objective:Prior studies have demonstrated an increased risk of developing cardiovascular and peri... more Objective:Prior studies have demonstrated an increased risk of developing cardiovascular and peripheral arterial disease (PAD) in patients with human immunodeficiency virus (HIV). However, the effect of chronic HIV infection in patients with preexisting PAD and requiring vascular intervention is unclear. In the present study, we assessed the differences in clinical presentation and perioperative outcomes for patients with PAD who had undergone revascularization or amputation with and without HIV infection.Methods:International Classification of Diseases, 9th and 10th Revisions, Clinical Modification, codes were used to identify patients with a prior diagnosis of PAD who had undergone lower extremity revascularization or amputation in the National Inpatient Sample (2003–2017). From this group, the patients were divided for analysis into those with and without HIV infection. Of the patients with HIV infection (PWHs), we identified additional subsets of patients: those with any prior or current diagnosis of an HIV-related illness, including acquired immunodeficiency syndrome, designated as symptomatic HIV, and those without such a diagnosis, designated as asymptomatic HIV infection. Propensity score matching was performed to create matched cohorts. Population-based comparative analyses were performed of the clinical characteristics of the HIV-infected and HIV-uninfected groups. Univariate and multivariate logistic regression analyses of the perioperative in-hospital outcomes were performed on the matched cohorts.Results:A total of 224,912 patients aged 18 to 85 years were identified who had been admitted with an established diagnosis of PAD and had undergone a lower extremity procedure. Of these patients, 1264 (0.56%) also had a diagnosis of HIV infection. Symptomatic PWHs were more likely to present with critical limb ischemia than were the HIV-uninfected patients or asymptomatic PWHs (66.2% vs 46.3% and 43.6%; P < .01). However, both asymptomatic and symptomatic PWHs were more likely to have required minor (7.5% and 6.7% vs 2.6%; P < .01) and major (12.9% and 27.4% vs 7.0%; P < .01) amputations than were matched HIV-uninfected controls. Although adjusted multivariate logistic regression analysis demonstrated symptomatic HIV infection to be a significant, independent predictor of in-hospital mortality (odds ratio, 2.46; 95% confidence interval, 1.37–4.40; P = .003), the perioperative mortality for the asymptomatic PWH was comparable to that of matched HIV-uninfected controls.Conclusions:Symptomatic PWHs, including patients living with acquired immunodeficiency syndrome, who had required a PAD-related procedure had presented with more advanced vascular disease and were most at risk of early perioperative mortality. However, the presentation and mortality between asymptomatic PWHs with well-controlled disease and HIV-uninfected patients were comparable. All PWHs with PAD were more likely to undergo lower extremity amputations than were HIV-uninfected matched controls. Asymptomatic, well-controlled HIV infection should not be a contraindication to elective PAD-related procedures because the mortality was similar to that of HIV-uninfected controls. However, the limb salvage rates might be lower for all PWHs with PAD, regardless of HIV disease severity. Taken together, these findings can improve perioperative risk stratification and surgical management of PAD in this high-risk population.
Journal of Immunology, May 1, 2017
Class II Transactivator (CIITA) induces transcription of MHC class II genes. This protein can pot... more Class II Transactivator (CIITA) induces transcription of MHC class II genes. This protein can potentially be used to improve genetic immunotherapies by converting non-immune cells into cells capable of presenting antigens to CD4+ T helper cells. However, CIITA expression is complex, tightly controlled and remains unclear whether distinct non-immune cells differ in the regulation of this transcription factor. In the present study, we describe a strategy to develop gene delivery systems capable of promoting the efficient expression of CIITA in non-immune cell lines and in primary human cells in an ex vivo skin explant model. A DNA plasmid and a lentiviral vector were produced, both carrying the human CIITA DNA sequence in silico designed to avoid cis-regulatory elements, and genetically optimized for expression efficacy in human cells. Different human cell types undergoing CIITA overexpression presented high-level de novo expression of MHC II molecules, validating the delivery systems as suitable tools for the evaluation of CIITA potential as a molecular adjuvant for genetic immunizations. Further, we directly compared different non-immune cells according to exogenous CIITA transcriptional activity, protein expression levels and proteasome degradation. Here we show for the first time that distinct types of non-immune cells differentially regulate the transcription factor, and ultimately the cell surface expression of MHC II, through a cell type-specific control of CIITA proteasomal degradation. Our findings contribute to the understanding of the CIITA post-translational regulation by non-immune cells, which can greatly influence the use of this regulator of MHC II genes as a vaccine adjuvant.
Journal of Virology, Jul 26, 2021
Despite the well-established contribution of CD8 T cells in HIV control, prior CD8 T cell-based H... more Despite the well-established contribution of CD8 T cells in HIV control, prior CD8 T cell-based HIV vaccines have failed to demonstrate any efficacy in preventing viral infection. One such vaccine, known as the MRKAd5 vaccine, showed a potential increased risk of viral infection among vaccine recipients.
Immunologic Research, 2006
The work in our laboratory addresses two interrelated areas of dendritic cell (DC) biology: (1) t... more The work in our laboratory addresses two interrelated areas of dendritic cell (DC) biology: (1) the role of DCs as mediators of feedback interactions between NK cells, CD8 + and CD4 + T cells; and (2) the possibility to use such feedback and the paradigms derived from anti-viral responses, to promote the induction of therapeutic immunity against cancer. We observed that CD8 + T cells and NK cells, the classical "effector" cells, also play "helper" roles, regulating ability of DCs to induce type-1 immune immunity, critical for fighting tumors and intracellular pathogens. Our work aims to delineate which pathways of NK and CD8 + T cell activation result in their helper activity, and to identify the molecular mechanisms allowing them to induce type-1 polarized DCs (DC1s) with selectively enhanced ability to promote type-1 responses and anti-cancer immunity. The results of these studies allowed us and our colleagues to design phase I/II clinical trials incorporating the paradigms of DC polarization and helper activity of effector cells in cancer immunotherapy. Dendric cells Cancer Immunotherapy Vaccines Th1 CTL NK cells Clinical trials Melanoma Colorectal cancer Prostate cancer
Journal of virus eradication, Dec 1, 2017
Journal of virus eradication, Dec 1, 2019
Background: Determination of replication-competent HIV (rcHIV) in monocytes (MO) in the setting o... more Background: Determination of replication-competent HIV (rcHIV) in monocytes (MO) in the setting of ART-suppressed HIV, remains a topic of intense interest, particularly due to the continued presence of neurocognitive decline as well as in our pursuit for an HIV cure.
Journal of virus eradication, Jul 1, 2016
Journal of Immunology, May 1, 2020
PLOS Pathogens, Aug 9, 2019
HIV-1 frequently escapes from CD8 T cell responses via HLA-I restricted adaptation, leading to th... more HIV-1 frequently escapes from CD8 T cell responses via HLA-I restricted adaptation, leading to the accumulation of adapted epitopes (AE). We previously demonstrated that AE compromise CD8 T cell responses during acute infection and are associated with poor clinical outcomes. Here, we examined the impact of AE on CD8 T cell responses and their biological relevance in chronic HIV infection (CHI). In contrast to acute infection, the majority of AE are immunogenic in CHI. Longitudinal analyses from acute to CHI showed an increased frequency and magnitude of AE-specific IFNγ responses compared to NAE-specific ones. These AE-specific CD8 T cells also were more cytotoxic to CD4 T cells. In addition, AE-specific CD8 T cells expressed lower levels of PD1 and CD57, as well as higher levels of CD28, suggesting a more activated and less exhausted phenotype. During CHI, viral sequencing identified AE-encoding strains as the dominant quasispecies. Despite increased CD4 T cell cytotoxicity, CD8 T cells responding to AE promoted dendritic cell (DC) maturation and CD4 T cell trans-infection perhaps explaining why AE are predominant in CHI. Taken together, our data suggests that the emergence of AE-specific CD8 T cell responses in CHI confers a selective advantage to the virus by promoting DC-mediated CD4 T cell trans-infection.
Journal of Immunology, May 1, 2020
T cells expressing the gamma delta (γδ) T cell receptor are a minor cell population, but a critic... more T cells expressing the gamma delta (γδ) T cell receptor are a minor cell population, but a critical component of innate immunity. γδ T cells can also influence adaptive immunity through their functional impact on dendritic cells (DC). To investigate the interaction between these cell types, we co-cultured peripheral blood γδ T cells from healthy volunteers with autologous monocyte derived DC. When immature DC (iDC) were co-cultured with resting human γδ T cells in the presence of zoledronate (Zol), drug that activates Vγ9δ2 T cells, DC maturation occurred. Blocking studies determined that γδ T cell-induced DC maturation was partially mediated by TNF-a and IFN-g. Moreover, γδ T cell-activated DC produced enhanced levels of IL-12p70. Interestingly, when activated effector γδ T cells were co-cultured with iDC in the presence of Zol a high degree iDC cell death was noted, suggesting a regulatory role of γδ T cells. When studying the impact of mature DC on γδ T cell function, we found that IL-12p70 deficient PGE-2 matured DC had a higher capacity to expand resting γδ T cells, that expressed higher levels of CD16, and were particularly less sensitive to apoptosis than those co-cultured with high IL-12p70-producing interferon-matured DC. Our findings show that the outcome of bidirectional cross talk between γδ T cells and DC is dependent on the context and activation status of each cell type, and that each regulate and modulate the immune function of the other.
Journal of Immunology, May 1, 2016
Combination strategies consisting of DC vaccines and suppression of immunoregulatory pathways suc... more Combination strategies consisting of DC vaccines and suppression of immunoregulatory pathways such as PD-1 blockade have been advocated to elicit optimal CTL responses in chronic diseases including cancer and HIV infection. We have shown that inactivated HIV-1 virus loaded, high IL-12 producing, mature, type-1 polarized DC (DC1) can activate CTL from naïve CD8+ T cell precursors that more effectively kill HIV-1-infected cells than CTL derived from memory CD8+ T cells. Here we tested DC1 transfected with an adenoviral (Ad) vector encoding anti-PD-1 antibody (DC.αPD1) enhancement of both primary as well as memory CTL responses to HIV-1. Ad-αPD1-transduced DC1 (DC.αPD1) secreted high levels of functional anti-PD1 Ab without affecting their phenotype or IL-12p70-producing capacity. We next compared HIV Gag peptide epitope-loaded DC.αPD1 to DC1 that were transfected with an empty vector for their ability to activate either purified, autologous naïve or memory HIV-1-specific CD8+ T cells from chronic HIV-1-infected participants of the Multicenter AIDS Cohort Study. When compared to the control DC1, antigen-loaded DC.αPD1 enhanced the overall magnitude of HIV-1-specific CTL responses induced, as determined by the expansion of HIV-1-peptide responsive CD107a and IFNγ expressing T cells. In contrast, the overall number HIV-1 antigen-reactive CTL derived from the naïve CD8+ T cell fraction sharply decreased when using the DC.αPD1-based approach. These results suggest previously unrecognized, opposing roles of the inhibitory receptor PD-1 in DC1-induced primary versus memory recall CD8+ T cell responses to HIV-1.
Journal of Immunology, May 1, 2019
While NK cells are well known for their killing effector function, they also play a critical role... more While NK cells are well known for their killing effector function, they also play a critical role as immune helper cells, providing innate alarm signals that shape and regulate the adaptive immune response. In chronic HIV-1 infection, an expanded population of CD56dim FcRγ deficient NK cells persists, similar to the ‘memory-like’ FcRγ− NK cell type identified in cytomegalovirus infection. The purpose of this study was to explore the phenotypic and functional relationship between these FcRγ− NK cells and the previously described IL-18-induced ‘memory-like’ NK helper cells in the setting of HIV-1 infection. We utilized HIV-1 seropositive participants of the Multicenter AIDS Cohort Study to measure baseline frequencies of peripheral blood FcRγ− NK cells by flow cytometry. We also treated NK cells for 24h with IL-18 alone, or in combination with IL-12, and assessed the phenotypic and functional impact on the FcRγ− and FcRγ+ subsets by flow cytometry. The frequencies of FcRγ− NK cells varied widely in HIV-1 infected men. IL-18 drove the differentiation of CD25+/CD83+ NK helper cells, which produced IFNγ and strongly diminished CD16 expression in response to IL-12. In contrast, FcRγ− NK cells did not respond to IL-18, illustrated by failure to express CD25 or CD83, to downregulate CD16 expression, and to produce IFNγ. FcRγ deficiency was also characterized by an attenuated capacity to express IL18Rα upon IL-18 and IL-12 co-activation. Our results indicate that ‘memory-like’ NK helper cells and FcRγ− NK cells are exclusive populations and suggest that HIV-1 drives the development of cytokine-exhausted FcRγ− NK cells that are unable to provide proper immune ‘help’ in response to innate activation signals.
Journal of Clinical Oncology
4143 Background: The prognostic role of the gut microbiome, which modulates cancer development an... more 4143 Background: The prognostic role of the gut microbiome, which modulates cancer development and therapeutic response, is unknown in patients with pancreatic ductal adenocarcinoma (PDAC). With increasing utilization of neoadjuvant therapy (NAT) prior to pancreatic cancer surgery, identification of patient-specific biologic signatures associated with NAT response a priori could help inform PDAC precision medicine. Thus, we assessed the influence of the baseline gut microbiome on clinical outcomes in patients with PDAC receiving NAT. Methods: Stool samples were collected at diagnosis from 42 consenting patients with localized PDAC intending to undergo NAT and surgical resection between 2018 and 2020. 16S rRNA sequencing was completed on pre-NAT stool and resected tumor samples. Microbiota alpha diversity and log transformed taxonomic classifications were utilized in multiple regression analyses to predict oncologic outcomes. Results: Five patients progressed during NAT and eight of ...
bioRxiv, 2021
Loss of function mutations in the human immunodeficiency virus (HIV) negative factor (Nef) gene a... more Loss of function mutations in the human immunodeficiency virus (HIV) negative factor (Nef) gene are associated with reduced viremia, robust T cell immune responses, and delayed acquired immunodeficiency syndrome (AIDS) progression in humans. In vitro studies have shown that mutations in the Nef dimerization interface significantly attenuate viral replication and impair host defense. However, in vivo, mechanistic studies on the role of Nef dimerization in HIV infection are lacking. Humanized rodents with human immune cells are robust platforms for investigating the interactions between HIV and the human immune system. The bone marrow-liver-thymus-spleen (BLTS) humanized mouse model carries human immune cells and lymphoid tissues that facilitate anti-viral immune responses. Here, we employed the BLTS-humanized mouse model to demonstrate that preventing Nef dimerization abrogates HIV viremia and the associated immune dysregulation. This suggests that Nef dimerization may be a therapeut...
Journal of Virus Eradication, 2015
Epidemiology and Infection, 2018
Reducing the risk of human immunodeficiency virus type 1 (HIV-1) transmission is still a public h... more Reducing the risk of human immunodeficiency virus type 1 (HIV-1) transmission is still a public health priority. The development of effective control strategies relies on the quantification of the effects of prophylactic and therapeutic measures in disease incidence. Although several assays can be used to estimate HIV incidence, these estimates are limited by the poor performance of these assays in distinguishing recent from long-standing infections. To address such limitation, we have developed an assay to titrate p24-specific IgG3 antibodies as a marker of recent infection. The assay is based on a recombinant p24 protein capable to detect total IgG antibodies in sera using a liquid micro array and enzyme-linked immunosorbent assay. Subsequently, the assay was optimised to detect and titrate anti-p24 IgG3 responses in a panel of sequential specimens from seroconverters over 24 months. The kinetics of p24-specific IgG3 titres revealed a transient peak in the 4 to 5-month period afte...
Gene Therapy, 2017
Development of potent class II transactivator gene delivery systems capable of inducing de novo M... more Development of potent class II transactivator gene delivery systems capable of inducing de novo MHC II expression in human cells, in vitro and ex vivo, Gene Therapy accepted article preview
Journal of Virology, 2018
Targeting the PD-1/PD-L1 immune checkpoint axis with signaling inhibitors has proven to be a powe... more Targeting the PD-1/PD-L1 immune checkpoint axis with signaling inhibitors has proven to be a powerful immunotherapeutic strategy to enhance the functional quality and survival of existing antigen-specific effector T cells. However, our study demonstrates that the context and timing of PD-1 signaling in T cells greatly impact the outcome of the effector response. In particular, we show that PD-1 activation plays a positive role during the DC-mediated initiation stage of the primary T cell response, while it serves as an inhibitory mechanism during the effector phase of the response. Therefore, caution should be taken in the design of therapies that include targeting of the PD-1/PD-L1 signaling pathway in order to avoid potential negative impacts on the induction of de novo T cell responses.
The Journal of Immunology, 2020
Despite being prolific innate killers, NK cells are also key helper cells in antiviral defense, i... more Despite being prolific innate killers, NK cells are also key helper cells in antiviral defense, influencing adaptive immune responses via interactions with dendritic cells (DCs). In addition to causing NK cell dysfunction, HIV-1 infection contributes to the expansion of a rare population of NK cells deficient in FcRγ (FcRγ−), an intracellular adaptor protein that associates with CD16. The implications of this inflated NK cell subset in treated HIV-1 infection remain unclear. In this study, we explored the helper function of human NK cells in chronic HIV-1 infection, with a particular focus on characterizing FcRγ− NK cells. Exposure of NK cells to innate DC-derived costimulatory factors triggered their helper activity, defined by their ability to produce IFN-γ and to drive the maturation of high IL-12–producing DCs. In this setting, however, FcRγ− NK cells were defective at producing the dominant DC-polarizing agent IFN-γ. The reduced responsiveness of FcRγ− NK cells to IL-18 in part...
Journal of Vascular Surgery, Oct 1, 2021
Objective:Prior studies have demonstrated an increased risk of developing cardiovascular and peri... more Objective:Prior studies have demonstrated an increased risk of developing cardiovascular and peripheral arterial disease (PAD) in patients with human immunodeficiency virus (HIV). However, the effect of chronic HIV infection in patients with preexisting PAD and requiring vascular intervention is unclear. In the present study, we assessed the differences in clinical presentation and perioperative outcomes for patients with PAD who had undergone revascularization or amputation with and without HIV infection.Methods:International Classification of Diseases, 9th and 10th Revisions, Clinical Modification, codes were used to identify patients with a prior diagnosis of PAD who had undergone lower extremity revascularization or amputation in the National Inpatient Sample (2003–2017). From this group, the patients were divided for analysis into those with and without HIV infection. Of the patients with HIV infection (PWHs), we identified additional subsets of patients: those with any prior or current diagnosis of an HIV-related illness, including acquired immunodeficiency syndrome, designated as symptomatic HIV, and those without such a diagnosis, designated as asymptomatic HIV infection. Propensity score matching was performed to create matched cohorts. Population-based comparative analyses were performed of the clinical characteristics of the HIV-infected and HIV-uninfected groups. Univariate and multivariate logistic regression analyses of the perioperative in-hospital outcomes were performed on the matched cohorts.Results:A total of 224,912 patients aged 18 to 85 years were identified who had been admitted with an established diagnosis of PAD and had undergone a lower extremity procedure. Of these patients, 1264 (0.56%) also had a diagnosis of HIV infection. Symptomatic PWHs were more likely to present with critical limb ischemia than were the HIV-uninfected patients or asymptomatic PWHs (66.2% vs 46.3% and 43.6%; P < .01). However, both asymptomatic and symptomatic PWHs were more likely to have required minor (7.5% and 6.7% vs 2.6%; P < .01) and major (12.9% and 27.4% vs 7.0%; P < .01) amputations than were matched HIV-uninfected controls. Although adjusted multivariate logistic regression analysis demonstrated symptomatic HIV infection to be a significant, independent predictor of in-hospital mortality (odds ratio, 2.46; 95% confidence interval, 1.37–4.40; P = .003), the perioperative mortality for the asymptomatic PWH was comparable to that of matched HIV-uninfected controls.Conclusions:Symptomatic PWHs, including patients living with acquired immunodeficiency syndrome, who had required a PAD-related procedure had presented with more advanced vascular disease and were most at risk of early perioperative mortality. However, the presentation and mortality between asymptomatic PWHs with well-controlled disease and HIV-uninfected patients were comparable. All PWHs with PAD were more likely to undergo lower extremity amputations than were HIV-uninfected matched controls. Asymptomatic, well-controlled HIV infection should not be a contraindication to elective PAD-related procedures because the mortality was similar to that of HIV-uninfected controls. However, the limb salvage rates might be lower for all PWHs with PAD, regardless of HIV disease severity. Taken together, these findings can improve perioperative risk stratification and surgical management of PAD in this high-risk population.
Journal of Immunology, May 1, 2017
Class II Transactivator (CIITA) induces transcription of MHC class II genes. This protein can pot... more Class II Transactivator (CIITA) induces transcription of MHC class II genes. This protein can potentially be used to improve genetic immunotherapies by converting non-immune cells into cells capable of presenting antigens to CD4+ T helper cells. However, CIITA expression is complex, tightly controlled and remains unclear whether distinct non-immune cells differ in the regulation of this transcription factor. In the present study, we describe a strategy to develop gene delivery systems capable of promoting the efficient expression of CIITA in non-immune cell lines and in primary human cells in an ex vivo skin explant model. A DNA plasmid and a lentiviral vector were produced, both carrying the human CIITA DNA sequence in silico designed to avoid cis-regulatory elements, and genetically optimized for expression efficacy in human cells. Different human cell types undergoing CIITA overexpression presented high-level de novo expression of MHC II molecules, validating the delivery systems as suitable tools for the evaluation of CIITA potential as a molecular adjuvant for genetic immunizations. Further, we directly compared different non-immune cells according to exogenous CIITA transcriptional activity, protein expression levels and proteasome degradation. Here we show for the first time that distinct types of non-immune cells differentially regulate the transcription factor, and ultimately the cell surface expression of MHC II, through a cell type-specific control of CIITA proteasomal degradation. Our findings contribute to the understanding of the CIITA post-translational regulation by non-immune cells, which can greatly influence the use of this regulator of MHC II genes as a vaccine adjuvant.
Journal of Virology, Jul 26, 2021
Despite the well-established contribution of CD8 T cells in HIV control, prior CD8 T cell-based H... more Despite the well-established contribution of CD8 T cells in HIV control, prior CD8 T cell-based HIV vaccines have failed to demonstrate any efficacy in preventing viral infection. One such vaccine, known as the MRKAd5 vaccine, showed a potential increased risk of viral infection among vaccine recipients.
Immunologic Research, 2006
The work in our laboratory addresses two interrelated areas of dendritic cell (DC) biology: (1) t... more The work in our laboratory addresses two interrelated areas of dendritic cell (DC) biology: (1) the role of DCs as mediators of feedback interactions between NK cells, CD8 + and CD4 + T cells; and (2) the possibility to use such feedback and the paradigms derived from anti-viral responses, to promote the induction of therapeutic immunity against cancer. We observed that CD8 + T cells and NK cells, the classical "effector" cells, also play "helper" roles, regulating ability of DCs to induce type-1 immune immunity, critical for fighting tumors and intracellular pathogens. Our work aims to delineate which pathways of NK and CD8 + T cell activation result in their helper activity, and to identify the molecular mechanisms allowing them to induce type-1 polarized DCs (DC1s) with selectively enhanced ability to promote type-1 responses and anti-cancer immunity. The results of these studies allowed us and our colleagues to design phase I/II clinical trials incorporating the paradigms of DC polarization and helper activity of effector cells in cancer immunotherapy. Dendric cells Cancer Immunotherapy Vaccines Th1 CTL NK cells Clinical trials Melanoma Colorectal cancer Prostate cancer
Journal of virus eradication, Dec 1, 2017
Journal of virus eradication, Dec 1, 2019
Background: Determination of replication-competent HIV (rcHIV) in monocytes (MO) in the setting o... more Background: Determination of replication-competent HIV (rcHIV) in monocytes (MO) in the setting of ART-suppressed HIV, remains a topic of intense interest, particularly due to the continued presence of neurocognitive decline as well as in our pursuit for an HIV cure.
Journal of virus eradication, Jul 1, 2016
Journal of Immunology, May 1, 2020
PLOS Pathogens, Aug 9, 2019
HIV-1 frequently escapes from CD8 T cell responses via HLA-I restricted adaptation, leading to th... more HIV-1 frequently escapes from CD8 T cell responses via HLA-I restricted adaptation, leading to the accumulation of adapted epitopes (AE). We previously demonstrated that AE compromise CD8 T cell responses during acute infection and are associated with poor clinical outcomes. Here, we examined the impact of AE on CD8 T cell responses and their biological relevance in chronic HIV infection (CHI). In contrast to acute infection, the majority of AE are immunogenic in CHI. Longitudinal analyses from acute to CHI showed an increased frequency and magnitude of AE-specific IFNγ responses compared to NAE-specific ones. These AE-specific CD8 T cells also were more cytotoxic to CD4 T cells. In addition, AE-specific CD8 T cells expressed lower levels of PD1 and CD57, as well as higher levels of CD28, suggesting a more activated and less exhausted phenotype. During CHI, viral sequencing identified AE-encoding strains as the dominant quasispecies. Despite increased CD4 T cell cytotoxicity, CD8 T cells responding to AE promoted dendritic cell (DC) maturation and CD4 T cell trans-infection perhaps explaining why AE are predominant in CHI. Taken together, our data suggests that the emergence of AE-specific CD8 T cell responses in CHI confers a selective advantage to the virus by promoting DC-mediated CD4 T cell trans-infection.
Journal of Immunology, May 1, 2020
T cells expressing the gamma delta (γδ) T cell receptor are a minor cell population, but a critic... more T cells expressing the gamma delta (γδ) T cell receptor are a minor cell population, but a critical component of innate immunity. γδ T cells can also influence adaptive immunity through their functional impact on dendritic cells (DC). To investigate the interaction between these cell types, we co-cultured peripheral blood γδ T cells from healthy volunteers with autologous monocyte derived DC. When immature DC (iDC) were co-cultured with resting human γδ T cells in the presence of zoledronate (Zol), drug that activates Vγ9δ2 T cells, DC maturation occurred. Blocking studies determined that γδ T cell-induced DC maturation was partially mediated by TNF-a and IFN-g. Moreover, γδ T cell-activated DC produced enhanced levels of IL-12p70. Interestingly, when activated effector γδ T cells were co-cultured with iDC in the presence of Zol a high degree iDC cell death was noted, suggesting a regulatory role of γδ T cells. When studying the impact of mature DC on γδ T cell function, we found that IL-12p70 deficient PGE-2 matured DC had a higher capacity to expand resting γδ T cells, that expressed higher levels of CD16, and were particularly less sensitive to apoptosis than those co-cultured with high IL-12p70-producing interferon-matured DC. Our findings show that the outcome of bidirectional cross talk between γδ T cells and DC is dependent on the context and activation status of each cell type, and that each regulate and modulate the immune function of the other.
Journal of Immunology, May 1, 2016
Combination strategies consisting of DC vaccines and suppression of immunoregulatory pathways suc... more Combination strategies consisting of DC vaccines and suppression of immunoregulatory pathways such as PD-1 blockade have been advocated to elicit optimal CTL responses in chronic diseases including cancer and HIV infection. We have shown that inactivated HIV-1 virus loaded, high IL-12 producing, mature, type-1 polarized DC (DC1) can activate CTL from naïve CD8+ T cell precursors that more effectively kill HIV-1-infected cells than CTL derived from memory CD8+ T cells. Here we tested DC1 transfected with an adenoviral (Ad) vector encoding anti-PD-1 antibody (DC.αPD1) enhancement of both primary as well as memory CTL responses to HIV-1. Ad-αPD1-transduced DC1 (DC.αPD1) secreted high levels of functional anti-PD1 Ab without affecting their phenotype or IL-12p70-producing capacity. We next compared HIV Gag peptide epitope-loaded DC.αPD1 to DC1 that were transfected with an empty vector for their ability to activate either purified, autologous naïve or memory HIV-1-specific CD8+ T cells from chronic HIV-1-infected participants of the Multicenter AIDS Cohort Study. When compared to the control DC1, antigen-loaded DC.αPD1 enhanced the overall magnitude of HIV-1-specific CTL responses induced, as determined by the expansion of HIV-1-peptide responsive CD107a and IFNγ expressing T cells. In contrast, the overall number HIV-1 antigen-reactive CTL derived from the naïve CD8+ T cell fraction sharply decreased when using the DC.αPD1-based approach. These results suggest previously unrecognized, opposing roles of the inhibitory receptor PD-1 in DC1-induced primary versus memory recall CD8+ T cell responses to HIV-1.
Journal of Immunology, May 1, 2019
While NK cells are well known for their killing effector function, they also play a critical role... more While NK cells are well known for their killing effector function, they also play a critical role as immune helper cells, providing innate alarm signals that shape and regulate the adaptive immune response. In chronic HIV-1 infection, an expanded population of CD56dim FcRγ deficient NK cells persists, similar to the ‘memory-like’ FcRγ− NK cell type identified in cytomegalovirus infection. The purpose of this study was to explore the phenotypic and functional relationship between these FcRγ− NK cells and the previously described IL-18-induced ‘memory-like’ NK helper cells in the setting of HIV-1 infection. We utilized HIV-1 seropositive participants of the Multicenter AIDS Cohort Study to measure baseline frequencies of peripheral blood FcRγ− NK cells by flow cytometry. We also treated NK cells for 24h with IL-18 alone, or in combination with IL-12, and assessed the phenotypic and functional impact on the FcRγ− and FcRγ+ subsets by flow cytometry. The frequencies of FcRγ− NK cells varied widely in HIV-1 infected men. IL-18 drove the differentiation of CD25+/CD83+ NK helper cells, which produced IFNγ and strongly diminished CD16 expression in response to IL-12. In contrast, FcRγ− NK cells did not respond to IL-18, illustrated by failure to express CD25 or CD83, to downregulate CD16 expression, and to produce IFNγ. FcRγ deficiency was also characterized by an attenuated capacity to express IL18Rα upon IL-18 and IL-12 co-activation. Our results indicate that ‘memory-like’ NK helper cells and FcRγ− NK cells are exclusive populations and suggest that HIV-1 drives the development of cytokine-exhausted FcRγ− NK cells that are unable to provide proper immune ‘help’ in response to innate activation signals.
Journal of Clinical Oncology
4143 Background: The prognostic role of the gut microbiome, which modulates cancer development an... more 4143 Background: The prognostic role of the gut microbiome, which modulates cancer development and therapeutic response, is unknown in patients with pancreatic ductal adenocarcinoma (PDAC). With increasing utilization of neoadjuvant therapy (NAT) prior to pancreatic cancer surgery, identification of patient-specific biologic signatures associated with NAT response a priori could help inform PDAC precision medicine. Thus, we assessed the influence of the baseline gut microbiome on clinical outcomes in patients with PDAC receiving NAT. Methods: Stool samples were collected at diagnosis from 42 consenting patients with localized PDAC intending to undergo NAT and surgical resection between 2018 and 2020. 16S rRNA sequencing was completed on pre-NAT stool and resected tumor samples. Microbiota alpha diversity and log transformed taxonomic classifications were utilized in multiple regression analyses to predict oncologic outcomes. Results: Five patients progressed during NAT and eight of ...
bioRxiv, 2021
Loss of function mutations in the human immunodeficiency virus (HIV) negative factor (Nef) gene a... more Loss of function mutations in the human immunodeficiency virus (HIV) negative factor (Nef) gene are associated with reduced viremia, robust T cell immune responses, and delayed acquired immunodeficiency syndrome (AIDS) progression in humans. In vitro studies have shown that mutations in the Nef dimerization interface significantly attenuate viral replication and impair host defense. However, in vivo, mechanistic studies on the role of Nef dimerization in HIV infection are lacking. Humanized rodents with human immune cells are robust platforms for investigating the interactions between HIV and the human immune system. The bone marrow-liver-thymus-spleen (BLTS) humanized mouse model carries human immune cells and lymphoid tissues that facilitate anti-viral immune responses. Here, we employed the BLTS-humanized mouse model to demonstrate that preventing Nef dimerization abrogates HIV viremia and the associated immune dysregulation. This suggests that Nef dimerization may be a therapeut...
Journal of Virus Eradication, 2015
Epidemiology and Infection, 2018
Reducing the risk of human immunodeficiency virus type 1 (HIV-1) transmission is still a public h... more Reducing the risk of human immunodeficiency virus type 1 (HIV-1) transmission is still a public health priority. The development of effective control strategies relies on the quantification of the effects of prophylactic and therapeutic measures in disease incidence. Although several assays can be used to estimate HIV incidence, these estimates are limited by the poor performance of these assays in distinguishing recent from long-standing infections. To address such limitation, we have developed an assay to titrate p24-specific IgG3 antibodies as a marker of recent infection. The assay is based on a recombinant p24 protein capable to detect total IgG antibodies in sera using a liquid micro array and enzyme-linked immunosorbent assay. Subsequently, the assay was optimised to detect and titrate anti-p24 IgG3 responses in a panel of sequential specimens from seroconverters over 24 months. The kinetics of p24-specific IgG3 titres revealed a transient peak in the 4 to 5-month period afte...
Gene Therapy, 2017
Development of potent class II transactivator gene delivery systems capable of inducing de novo M... more Development of potent class II transactivator gene delivery systems capable of inducing de novo MHC II expression in human cells, in vitro and ex vivo, Gene Therapy accepted article preview
Journal of Virology, 2018
Targeting the PD-1/PD-L1 immune checkpoint axis with signaling inhibitors has proven to be a powe... more Targeting the PD-1/PD-L1 immune checkpoint axis with signaling inhibitors has proven to be a powerful immunotherapeutic strategy to enhance the functional quality and survival of existing antigen-specific effector T cells. However, our study demonstrates that the context and timing of PD-1 signaling in T cells greatly impact the outcome of the effector response. In particular, we show that PD-1 activation plays a positive role during the DC-mediated initiation stage of the primary T cell response, while it serves as an inhibitory mechanism during the effector phase of the response. Therefore, caution should be taken in the design of therapies that include targeting of the PD-1/PD-L1 signaling pathway in order to avoid potential negative impacts on the induction of de novo T cell responses.
The Journal of Immunology, 2020
Despite being prolific innate killers, NK cells are also key helper cells in antiviral defense, i... more Despite being prolific innate killers, NK cells are also key helper cells in antiviral defense, influencing adaptive immune responses via interactions with dendritic cells (DCs). In addition to causing NK cell dysfunction, HIV-1 infection contributes to the expansion of a rare population of NK cells deficient in FcRγ (FcRγ−), an intracellular adaptor protein that associates with CD16. The implications of this inflated NK cell subset in treated HIV-1 infection remain unclear. In this study, we explored the helper function of human NK cells in chronic HIV-1 infection, with a particular focus on characterizing FcRγ− NK cells. Exposure of NK cells to innate DC-derived costimulatory factors triggered their helper activity, defined by their ability to produce IFN-γ and to drive the maturation of high IL-12–producing DCs. In this setting, however, FcRγ− NK cells were defective at producing the dominant DC-polarizing agent IFN-γ. The reduced responsiveness of FcRγ− NK cells to IL-18 in part...