Etude de la dynamique des réponses immunitaires et génération d'anticorps monoclonaux à visée thérapeutique dans la pathogenèse du SIV/VIH

HIV-1 infection induces numerous deregulations of immune responses and persistence of latent HIV-1 reservoirs. A better understanding of the cellular and molecular events associated to these mechanisms is necessary to develop a long-lasting remission of HIV-1. In this regard, our first study confirms in HIV+ patients the presence of CD32a+ CD4+ T cells initially proposed as specific to latent HIV reservoir. However, our data indicate that these cells are also found in seronegative individuals. Moreover, these results reveal the high diversity and dynamics of these cells at different stages of the infection.In our second study, we looked over myeloid cells, which play a key role in setting up immune responses. Our results show that these cells also undergo abundance modifications from the early phase of HIV-1 infection. This study highlights a particular cDC2 subpopulation overrepresented in HIV controllers patients.Finally, we were interested in therapeutic strategies aimed to restore the function of the immune system against HIV-1 by the blockade of immunomodulatory receptors. In this regard and for our latest study, we developed two monoclonal antibodies (mAb) able to block the interaction of the inhibitory-receptors LILRB1 and/or LILRB2 with their MHC-I ligands in both humans and macaques. These blocking mAb could pave the way for preclinical studies in macaque model of SIV infection and help to reveal the in vivo involvement of these receptors in the pathophysiology of SIV/HIV infection.L’infection par le VIH-1 engendre une dérégulation des réponses immunitaires ainsi que la persistance de réservoirs VIH-1 latents. Une meilleure compréhension des évènements cellulaires et moléculaires impliqués dans ces mécanismes est nécessaire pour élaborer de nouvelles thérapies permettant une rémission durable du VIH-1. A cet égard, notre première étude confirme chez des patients VIH+ la présence de cellules T CD4+ CD32a+ initialement proposées comme spécifiques du réservoir latent du VIH-1. Néanmoins, nos données indiquent que ces cellules sont aussi retrouvées chez des individus séronégatifs. Ces résultats révèlent également l’importante diversité et la dynamique de ces cellules à différentes phases de l’infection.Dans une seconde étude, nous avons examiné les cellules myéloïdes, qui jouent un rôle clé dans la mise en place des réponses immunitaires. Nos résultats montrent que ces cellules subissent aussi des modifications d’abondances dès la phase précoce de l’infection au VIH-1. Cette étude met également en évidence une sous-population particulière de cDC2 surreprésentée chez les patients contrôleurs du VIH.Enfin, nous nous sommes intéressés aux stratégies thérapeutiques visant à restaurer la fonction du système immunitaire contre le VIH-1 par le blocage de certains récepteurs immunomodulateurs. Dans ce contexte et pour notre dernière étude, nous avons développé deux anticorps monoclonaux (AcM) bloquant l’interaction in vitro des récepteurs inhibiteurs LILRB1 et/ou LILRB2 avec leurs ligands du CMH-I, à la fois chez l’Homme et le macaque. Ces AcM pourraient ouvrir la voie à des études précliniques dans le modèle SIV et ainsi révéler l’implication in vivo de ces récepteurs dans la physiopathologie de l’infection au SIV/VIH

Study of the dynamic of immune responses and generation of monoclonal antibodies for therapeutic purposes in SIV/HIV pathogenesis

L’infection par le VIH-1 engendre une dérégulation des réponses immunitaires ainsi que la persistance de réservoirs VIH-1 latents. Une meilleure compréhension des évènements cellulaires et moléculaires impliqués dans ces mécanismes est nécessaire pour élaborer de nouvelles thérapies permettant une rémission durable du VIH-1. A cet égard, notre première étude confirme chez des patients VIH+ la présence de cellules T CD4+ CD32a+ initialement proposées comme spécifiques du réservoir latent du VIH-1. Néanmoins, nos données indiquent que ces cellules sont aussi retrouvées chez des individus séronégatifs. Ces résultats révèlent également l’importante diversité et la dynamique de ces cellules à différentes phases de l’infection.Dans une seconde étude, nous avons examiné les cellules myéloïdes, qui jouent un rôle clé dans la mise en place des réponses immunitaires. Nos résultats montrent que ces cellules subissent aussi des modifications d’abondances dès la phase précoce de l’infection au VIH-1. Cette étude met également en évidence une sous-population particulière de cDC2 surreprésentée chez les patients contrôleurs du VIH.Enfin, nous nous sommes intéressés aux stratégies thérapeutiques visant à restaurer la fonction du système immunitaire contre le VIH-1 par le blocage de certains récepteurs immunomodulateurs. Dans ce contexte et pour notre dernière étude, nous avons développé deux anticorps monoclonaux (AcM) bloquant l’interaction in vitro des récepteurs inhibiteurs LILRB1 et/ou LILRB2 avec leurs ligands du CMH-I, à la fois chez l’Homme et le macaque. Ces AcM pourraient ouvrir la voie à des études précliniques dans le modèle SIV et ainsi révéler l’implication in vivo de ces récepteurs dans la physiopathologie de l’infection au SIV/VIH.HIV-1 infection induces numerous deregulations of immune responses and persistence of latent HIV-1 reservoirs. A better understanding of the cellular and molecular events associated to these mechanisms is necessary to develop a long-lasting remission of HIV-1. In this regard, our first study confirms in HIV+ patients the presence of CD32a+ CD4+ T cells initially proposed as specific to latent HIV reservoir. However, our data indicate that these cells are also found in seronegative individuals. Moreover, these results reveal the high diversity and dynamics of these cells at different stages of the infection.In our second study, we looked over myeloid cells, which play a key role in setting up immune responses. Our results show that these cells also undergo abundance modifications from the early phase of HIV-1 infection. This study highlights a particular cDC2 subpopulation overrepresented in HIV controllers patients.Finally, we were interested in therapeutic strategies aimed to restore the function of the immune system against HIV-1 by the blockade of immunomodulatory receptors. In this regard and for our latest study, we developed two monoclonal antibodies (mAb) able to block the interaction of the inhibitory-receptors LILRB1 and/or LILRB2 with their MHC-I ligands in both humans and macaques. These blocking mAb could pave the way for preclinical studies in macaque model of SIV infection and help to reveal the in vivo involvement of these receptors in the pathophysiology of SIV/HIV infection

Leukocyte Immunoglobulin-Like Receptors in Regulating the Immune Response in Infectious Diseases: A Window of Opportunity to Pathogen Persistence and a Sound Target in Therapeutics

International audienceImmunoregulatory receptors are essential for orchestrating an immune response as well as appropriate inflammation in infectious and non-communicable diseases. Among them, leukocyte immunoglobulin-like receptors (LILRs) consist of activating and inhibitory receptors that play an important role in regulating immune responses modulating the course of disease progression. On the one hand, inhibitory LILRs constitute a safe-guard system that mitigates the inflammatory response, allowing a prompt return to immune homeostasis. On the other hand, because of their unique capacity to attenuate immune responses, pathogens use inhibitory LILRs to evade immune recognition, thus facilitating their persistence within the host. Conversely, the engagement of activating LILRs triggers immune responses and the production of inflammatory mediators to fight microbes. However, their heightened activation could lead to an exacerbated immune response and persistent inflammation with major consequences on disease outcome and autoimmune disorders. Here, we review the genetic organisation, structure and ligands of LILRs as well as their role in regulating the immune response and inflammation. We also discuss the LILR-based strategies that pathogens use to evade immune responses. A better understanding of the contribution of LILRs to host–pathogen interactions is essential to define appropriate treatments to counteract the severity and/or persistence of pathogens in acute and chronic infectious diseases lacking efficient treatments

Mass Cytometry Analysis Reveals Complex Cell-State Modifications of Blood Myeloid Cells During HIV Infection

International audienceDendritic cells (DC), which are involved in orchestrating early immune responses against pathogens, are dysregulated in their function by HIV infection. This dysregulation likely contributes to tip the balance toward viral persistence. Different DC subpopulations, including classical (cDCs) and plasmacytoid (pDCs) dendritic cells, are subjected to concomitant inflammatory and immunoregulatory events during HIV infection, which hampers the precise characterization of their regulation through classical approaches. Here, we carried out mass cytometry analysis of blood samples from early HIV-infected patients that were longitudinally collected before and after 1 year of effective combination antiretroviral therapy (cART). Blood samples from HIV controller patients who naturally control the infection were also included. Our data revealed that plasma HIV RNA level was positively associated with a loss of cDC and pDC subpopulations that display high expression of LILR immunomodulatory receptors. Conversely, specific monocyte populations co-expressing high levels of HLA-I, 3 immunomodulatory receptors, CD64, LILRA2, and LILRB4, and the restriction factor CD317 (also known as BST2/Tetherin), were more abundant in early HIV-infection. Finally, our analysis revealed that the blood of HIV controller patients contained in a higher abundance a particular subtype of CD1c+ cDCs, characterized by elevated co-expression of CD32b inhibitory receptor and HLA-DR antigen-presentation molecules. Overall, this study unravels the modifications induced in DC and monocyte subpopulations in different HIV+ conditions, and provides a better comprehension of the immune regulation/dysregulation mechanisms induced during this viral infection

Mass Cytometry Analysis Reveals the Landscape and Dynamics of CD32a+ CD4+ T Cells From Early HIV Infection to Effective cART

International audienceCD32a has been proposed as a specific marker of latently HIV-infected CD4 + T cells. However, CD32a was recently found to be expressed on CD4 + T cells of healthy donors, leading to controversy on the relevance of this marker in HIV persistence. Here, we used mass cytometry to characterize the landscape and variation in the abundance of CD32a + CD4 + T cells during HIV infection. To this end, we analyzed CD32a + CD4 + T cells in primary HIV infection before and after effective combination antiretroviral therapy (cART) and in healthy donors. We found that CD32a + CD4 + T cells include heterogeneous subsets that are differentially affected by HIV infection. Our analysis revealed that naive (N), central memory (CM), and effector/memory (Eff/Mem) CD32a + CD4 + T-cell clusters that co-express LILRA2-and CD64-activating receptors were more abundant in primary HIV infection and cART stages. Conversely, LILRA2 − CD32a + CD4 + T-cell clusters of either the TN, TCM, or TEff/Mem phenotype were more abundant in healthy individuals. Finally, an activated CD32a + CD4 + TEff/Mem cell cluster co-expressing LILRA2, CD57, and NKG2C was more abundant in all HIV stages, particularly during primary HIV infection. Overall, our data show that multiple abundance modifications of CD32a + CD4 + T-cell subsets occur in the early phase of HIV infection, and some of which are conserved after effective cART. Our study brings a better comprehension of the relationship between CD32a expression and CD4 + T cells during HIV infection

image_9_Mass Cytometry Analysis Reveals the Landscape and Dynamics of CD32a+ CD4+ T Cells From Early HIV Infection to Effective cART.PDF

<p>CD32a has been proposed as a specific marker of latently HIV-infected CD4⁺ T cells. However, CD32a was recently found to be expressed on CD4⁺ T cells of healthy donors, leading to controversy on the relevance of this marker in HIV persistence. Here, we used mass cytometry to characterize the landscape and variation in the abundance of CD32a⁺ CD4⁺ T cells during HIV infection. To this end, we analyzed CD32a⁺ CD4⁺ T cells in primary HIV infection before and after effective combination antiretroviral therapy (cART) and in healthy donors. We found that CD32a⁺ CD4⁺ T cells include heterogeneous subsets that are differentially affected by HIV infection. Our analysis revealed that naive (_N), central memory (_CM), and effector/memory (_Eff/Mem) CD32a⁺ CD4⁺ T-cell clusters that co-express LILRA2- and CD64-activating receptors were more abundant in primary HIV infection and cART stages. Conversely, LILRA2⁻ CD32a⁺ CD4⁺ T-cell clusters of either the T_N, T_CM, or T_Eff/Mem phenotype were more abundant in healthy individuals. Finally, an activated CD32a⁺ CD4⁺ T_Eff/Mem cell cluster co-expressing LILRA2, CD57, and NKG2C was more abundant in all HIV stages, particularly during primary HIV infection. Overall, our data show that multiple abundance modifications of CD32a⁺ CD4⁺ T-cell subsets occur in the early phase of HIV infection, and some of which are conserved after effective cART. Our study brings a better comprehension of the relationship between CD32a expression and CD4⁺ T cells during HIV infection.</p

image_8_Mass Cytometry Analysis Reveals the Landscape and Dynamics of CD32a+ CD4+ T Cells From Early HIV Infection to Effective cART.PDF

<p>CD32a has been proposed as a specific marker of latently HIV-infected CD4⁺ T cells. However, CD32a was recently found to be expressed on CD4⁺ T cells of healthy donors, leading to controversy on the relevance of this marker in HIV persistence. Here, we used mass cytometry to characterize the landscape and variation in the abundance of CD32a⁺ CD4⁺ T cells during HIV infection. To this end, we analyzed CD32a⁺ CD4⁺ T cells in primary HIV infection before and after effective combination antiretroviral therapy (cART) and in healthy donors. We found that CD32a⁺ CD4⁺ T cells include heterogeneous subsets that are differentially affected by HIV infection. Our analysis revealed that naive (_N), central memory (_CM), and effector/memory (_Eff/Mem) CD32a⁺ CD4⁺ T-cell clusters that co-express LILRA2- and CD64-activating receptors were more abundant in primary HIV infection and cART stages. Conversely, LILRA2⁻ CD32a⁺ CD4⁺ T-cell clusters of either the T_N, T_CM, or T_Eff/Mem phenotype were more abundant in healthy individuals. Finally, an activated CD32a⁺ CD4⁺ T_Eff/Mem cell cluster co-expressing LILRA2, CD57, and NKG2C was more abundant in all HIV stages, particularly during primary HIV infection. Overall, our data show that multiple abundance modifications of CD32a⁺ CD4⁺ T-cell subsets occur in the early phase of HIV infection, and some of which are conserved after effective cART. Our study brings a better comprehension of the relationship between CD32a expression and CD4⁺ T cells during HIV infection.</p

image_1_Mass Cytometry Analysis Reveals the Landscape and Dynamics of CD32a+ CD4+ T Cells From Early HIV Infection to Effective cART.PDF

<p>CD32a has been proposed as a specific marker of latently HIV-infected CD4⁺ T cells. However, CD32a was recently found to be expressed on CD4⁺ T cells of healthy donors, leading to controversy on the relevance of this marker in HIV persistence. Here, we used mass cytometry to characterize the landscape and variation in the abundance of CD32a⁺ CD4⁺ T cells during HIV infection. To this end, we analyzed CD32a⁺ CD4⁺ T cells in primary HIV infection before and after effective combination antiretroviral therapy (cART) and in healthy donors. We found that CD32a⁺ CD4⁺ T cells include heterogeneous subsets that are differentially affected by HIV infection. Our analysis revealed that naive (_N), central memory (_CM), and effector/memory (_Eff/Mem) CD32a⁺ CD4⁺ T-cell clusters that co-express LILRA2- and CD64-activating receptors were more abundant in primary HIV infection and cART stages. Conversely, LILRA2⁻ CD32a⁺ CD4⁺ T-cell clusters of either the T_N, T_CM, or T_Eff/Mem phenotype were more abundant in healthy individuals. Finally, an activated CD32a⁺ CD4⁺ T_Eff/Mem cell cluster co-expressing LILRA2, CD57, and NKG2C was more abundant in all HIV stages, particularly during primary HIV infection. Overall, our data show that multiple abundance modifications of CD32a⁺ CD4⁺ T-cell subsets occur in the early phase of HIV infection, and some of which are conserved after effective cART. Our study brings a better comprehension of the relationship between CD32a expression and CD4⁺ T cells during HIV infection.</p

image_3_Mass Cytometry Analysis Reveals the Landscape and Dynamics of CD32a+ CD4+ T Cells From Early HIV Infection to Effective cART.PDF

<p>CD32a has been proposed as a specific marker of latently HIV-infected CD4⁺ T cells. However, CD32a was recently found to be expressed on CD4⁺ T cells of healthy donors, leading to controversy on the relevance of this marker in HIV persistence. Here, we used mass cytometry to characterize the landscape and variation in the abundance of CD32a⁺ CD4⁺ T cells during HIV infection. To this end, we analyzed CD32a⁺ CD4⁺ T cells in primary HIV infection before and after effective combination antiretroviral therapy (cART) and in healthy donors. We found that CD32a⁺ CD4⁺ T cells include heterogeneous subsets that are differentially affected by HIV infection. Our analysis revealed that naive (_N), central memory (_CM), and effector/memory (_Eff/Mem) CD32a⁺ CD4⁺ T-cell clusters that co-express LILRA2- and CD64-activating receptors were more abundant in primary HIV infection and cART stages. Conversely, LILRA2⁻ CD32a⁺ CD4⁺ T-cell clusters of either the T_N, T_CM, or T_Eff/Mem phenotype were more abundant in healthy individuals. Finally, an activated CD32a⁺ CD4⁺ T_Eff/Mem cell cluster co-expressing LILRA2, CD57, and NKG2C was more abundant in all HIV stages, particularly during primary HIV infection. Overall, our data show that multiple abundance modifications of CD32a⁺ CD4⁺ T-cell subsets occur in the early phase of HIV infection, and some of which are conserved after effective cART. Our study brings a better comprehension of the relationship between CD32a expression and CD4⁺ T cells during HIV infection.</p