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Control of HIV-induced MDSC expansion and immunosuppression by cytotoxic lymphocytes

细胞毒性淋巴细胞控制 HIV 诱导的 MDSC 扩增和免疫抑制

基本信息

批准号：
10559918
负责人：
Silke Paust
金额：
$ 26.63万
依托单位：
SCRIPPS RESEARCH INSTITUTE, THE
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-01 至 2024-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10559918
关键词：
Acquired Immunodeficiency Syndrome Animals Apoptosis CD4 Positive T Lymphocytes CD8-Positive T-Lymphocytes Cell surface Cells Cessation of life Cytotoxic T-Lymphocytes Data Disease Frequencies Future HIV HIV Infections Human Immune Immune System Diseases Immune system Immunosuppression Immunotherapy In Vitro Incidence Infection prevention Inflammatory Investigation Knowledge Ligands Ligation Link Lymphocyte Mediating Modeling Myeloid-derived suppressor cells Natural Killer Cells Necrosis Pathway interactions Persons Physiological Plasma Population Process Proteins Publishing Recombinants Recovery Regulatory T-Lymphocyte Role Serum Stimulus TNF gene TNFRSF10A gene TNFRSF10B gene TNFSF10 gene Testing Therapeutic Viral Work antiretroviral therapy cancer immunotherapy cell killing cell type cytotoxic granulocyte immune checkpoint immune checkpoint blockade improved in vivo insight monocyte mouse model neutrophil novel peripheral blood prevent receptor tool

项目摘要

Elevated frequencies of granulocytic myeloid-derived suppressor cells (PMN-MDSCs) precede and contribute to immune dysfunction in persons living with HIV (PLHIV). The underlying mechanisms of this dysregulation are poorly understood. Potential mechanisms under investigation include PMN-MDSCs impacting CD4+ T cell recovery, expanding T-regulatory cells (T-reg), inducing immune checkpoints (IC), and suppressing the antiviral functions of cytotoxic lymphocytes. While the initiation of combined antiretroviral therapy (cART) can reduce peripheral blood PMN-MDSCs levels in PLHIV, PMN-MDSCs levels can remain elevated despite cART, and cART does not remedy all PMN-MDSC-induced immune dysfunction. The tumor-necrosis-factor-related- apoptosis-inducing-ligand (TRAIL) is a cell-surface and secreted apoptosis-inducing protein expressed by activated human Natural Killer (NK) cells and cytotoxic T lymphocytes (CD8+ T cells, CTL). TRAIL ligation of its receptors (also called death receptors (DRs)) induces apoptosis on DR-expressing cells. PMN-MDSCs express TRAIL-R1 (DR4) and 2 (DR5). Recently published work showed a link between serum levels of agonistic soluble TRAIL (sTRAIL) and PMN-MDSC frequency in PLHIV. Early in HIV infection, PMN-MDSC frequency inversely correlates with plasma levels of sTRAIL, and recombinant TRAIL induces PMN-MDSC apoptosis in vitro. Thus, DR ligation, currently being explored as an immunotherapy for cancer, may be a way to reduce PMN-MDSCs frequencies in PLHIV. In addition to TRAIL, PMN-MDSCs also express NKG2D-ligands. NKG2D is an NK cell activating receptor and a positive costimulatory receptor of human CTLs, and NKG2D-ligand expression renders PMN-MDSCs highly susceptible to NK cell killing. However, despite data implicating PMN-MDSCs as essential contributors to immune dysfunction and HIV disease, approaches targeting PMN-MDSCs in PLHIV have yet to be explored. Using a mouse model with a competent and HIV susceptible humanized immune system, we found that PMN-MDSCs expand rapidly upon HIV infection. Like in humans, PMN-MDSCs correlated positively with HIV viral titers and T-reg in this model. Mechanistic studies in cytotoxic lymphocyte-depleted animals revealed that NK cells and perhaps also CTLs controlled PMN-MDSC expansion, expressed NKG2D, and upregulated TRAIL upon HIV infection. We propose to explore the mechanisms by which PMN-MDSC and consequent Treg expansions are controlled. We propose to test the hypothesis that therapeutic PMN-MDSCs reduction during HIV infection prevents PMN-MDSCs-caused immune dysfunction, improving viral control. Our studies will leverage novel tools and therapeutic approaches to define the impact of the TRAIL and NKG2D pathways on controlling PMN-MDSC and resultant Treg expansion upon HIV infection. We will explore therapeutic strategies to reduce PMN-MDSC and prevent T-reg expansion upon HIV infection in vivo. The knowledge gained from our work will facilitate new insight into the mechanisms that control or exacerbate HIV-infection-induced immune disturbance and disease.

粒细胞髓源性抑制细胞（PMN-MDSCs）的频率升高是导致