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The relationship between NK cell counts during primary infection and disease progression or immune restoration after antiretroviral treatment (ART) was explored. We followed 462 individuals with HIV infection and measured their NK, CD4+ T, CD8+ T cell counts and viral loads. Our data showed that individuals with high NK cell counts had much lower viral loads and higher CD4+ T cell counts. NK cell counts during primary infection were negatively correlated with viral set-point and viral loads at one-year-infection point, and positively correlated with CD4+ T cell counts at one-year-infection and one-year-ART point. Moreover, the NK cell counts during primary infection can predict HIV disease progression and immune restoration after ART. In conclusion, NK cell counts during primary infection represents a potential predictive biomarker to predict HIV disease prognosis in the clinic.

Background Despite the effective antiretroviral treatment (ART) of HIV-infected individuals, HIV persists in a small pool. Central memory CD4+ T cells (Tcm) make a major contribution to HIV persistence. We found that unlike HLA-DR, CD38 is highly expressed on the Tcm of HIV-infected subjects receiving ART for > 5 years. It has been reported that the half-life of total and episomal HIV DNA in the CD4+CD38+ T cell subset, exhibits lower decay rates at 12 weeks of ART. Whether CD38 contributes to HIV latency in HIV-infected individuals receiving long-term ART is yet to be addressed. Methods Peripheral blood mononuclear cells (PBMCs) were isolated from the whole blood of HIV-infected subjects receiving suppressive ART. The immunophenotyping, proliferation and apoptosis of CD4+ T cell subpopulations were detected by flow cytometry, and the level of CD38 mRNA and total HIV DNA were measured using real-time PCR and digital droplet PCR, respectively. A negative binomial regression model was used to determine the correlation between CD4+CD38+ Tcm and total HIV DNA in CD4+ T cells. Results CD38 was highly expressed on CD4+ Tcm cells from HIV infected individuals on long-term ART. Comparing with HLA-DR−Tcm and CD4+HLA-DR+ T cells, CD4+CD38+ Tcm cells displayed lower levels of activation (CD25 and CD69) and higher levels of CD127 expression. The proportion of CD38+ Tcm, but not CD38− Tcm cells can predict the total HIV DNA in the CD4+ T cells and the CD38+ Tcm subset harbored higher total HIV DNA copy numbers than the CD38− Tcm subset. After transfected with CD38 si-RNA in CD4+ T cells, the proliferation of CD4+ T cells was inhibited. Conclusion The current date indicates that CD4+CD38+ Tcm cells contribute to HIV persistence in HIV-infected individuals on long-term ART. Our study provides a potential target to resolve HIV persistence.

The percentage of human CD56−CD16+ NK cells increases during chronic infection with human HIV; however, the biologic role of CD56−CD16+ NK cells in HIV infection is unclear. Our results demonstrate that the percentage of CD56−CD16+ NK cells producing IL-10 and TGF-β was higher than CD56dimCD16+ NK cells. CD56−CD16+ NK cells could inhibit IFN-γ production by autologous CD8+ T cells, and this inhibition could be partially reversed by anti-IL-10, anti-TGF-β, or anti-PD-L1 mAbs. CD56−CD16+ NK cells are potential targets for the development of novel immune therapies against HIV infection.

Human immunodeficiency virus (HIV) actively modulates the protein stability of host cells to optimize viral replication. To systematically examine this modulation in HIV infection, we used isobaric tag-based mass spectrometry to quantify changes in the abundance of over 14,000 proteins during HIV-1 infection of human primary CD4+ T cells. We identified P-selectin glycoprotein ligand 1 (PSGL-1) as an HIV-1 restriction factor downregulated by HIV-1 Vpu, which binds to PSGL-1 and induces its ubiquitination and degradation through the ubiquitin ligase SCFβ-TrCP2. PSGL-1 is induced by interferon-γ in activated CD4+ T cells to inhibit HIV-1 reverse transcription and potently block viral infectivity by incorporating in progeny virions. This infectivity block is antagonized by Vpu via PSGL-1 degradation. We further show that PSGL-1 knockdown can significantly abolish the anti-HIV activity of interferon-γ in primary CD4+ T cells. Our study identifies an HIV restriction factor and a key mediator of interferon-γ's anti-HIV activity.

Background T cell immunoglobulin and mucin domain-containing-3 (Tim-3) is a negative regulator expressed on T cells, and is also expressed on natural killer (NK) cells. The function of Tim-3 chiefly restricts IFNγ-production in T cells, however, the impact of Tim-3 on NK cell function has not been clearly elucidated. Results In this study, we demonstrated down-regulation of Tim-3 expression on NK cells while Tim-3 is upregulated on CD4+ T cells during HIV infection. Functional assays indicated that Tim-3 mediates suppression of CD107a degranulation in NK cells and CD4+ T cells, while it fails to inhibit the production of IFN-γ by NK cells. Analyses of downstream pathways using an antibody to block Tim-3 function demonstrated that Tim-3 can inhibit ERK and NFκB p65 signaling; however, it failed to suppress the NFAT pathway. Further, we found that the NFAT activity in NK cells was much higher than that in CD4+ T cells, indicating that NFAT pathway is important for promotion of IFN-γ production by NK cells. Conclusions Thus, our data show that the expression of Tim-3 on NK cells is insufficient to inhibit IFN-γ production. Collectively, our findings demonstrate a potential mechanism of Tim-3 regulation of NK cells and a target for HIV infection immunotherapy.

Significance PSGL-1 and CD43 are surface glycoproteins expressed on blood CD4 T cells to bind to selectins for T cell tethering, rolling, and migration into inflamed tissues. The PSGL-1 level is greatly up-regulated during inflammation. Here we found that PSGL-1 and CD43 expression inhibits HIV spreading infection. Mechanistically, PSGL-1 blocks the binding of virus particles to target cells. PSGL-1–mediated suppression of virus infectivity extends to another retrovirus—murine leukemia virus—and to influenza A virus. These results further our understanding of virus–host interactions and help elucidate mechanisms by which cellular host factors regulate viral infection and pathogenesis., P-selectin glycoprotein ligand-1 (PSGL-1) is a dimeric, mucin-like, 120-kDa glycoprotein that binds to P-, E-, and L-selectins. PSGL-1 is expressed primarily on the surface of lymphoid and myeloid cells and is up-regulated during inflammation to mediate leukocyte tethering and rolling on the surface of endothelium for migration into inflamed tissues. Although it has been reported that PSGL-1 expression inhibits HIV-1 replication, the mechanism of PSGL-1–mediated anti-HIV activity remains to be elucidated. Here we report that PSGL-1 in virions blocks the infectivity of HIV-1 particles by preventing the binding of particles to target cells. This inhibitory activity is independent of the viral glycoprotein present on the virus particle; the binding of particles bearing the HIV-1 envelope glycoprotein or vesicular stomatitis virus G glycoprotein or even lacking a viral glycoprotein is impaired by PSGL-1. Mapping studies show that the extracellular N-terminal domain of PSGL-1 is necessary for its anti–HIV-1 activity, and that the PSGL-1 cytoplasmic tail contributes to inhibition. In addition, we demonstrate that the PSGL-1–related monomeric E-selectin–binding glycoprotein CD43 also effectively blocks HIV-1 infectivity. HIV-1 infection, or expression of either Vpu or Nef, down-regulates PSGL-1 from the cell surface; expression of Vpu appears to be primarily responsible for enabling the virus to partially escape PSGL-1–mediated restriction. Finally, we show that PSGL-1 inhibits the infectivity of other viruses, such as murine leukemia virus and influenza A virus. These findings demonstrate that PSGL-1 is a broad-spectrum antiviral host factor with a unique mechanism of action.

Currently there is no effective antiviral therapy for SARS-CoV-2 infection, which frequently leads to fatal inflammatory responses and acute lung injury. Here, we discuss the various mechanisms of SARS-CoV-mediated inflammation. We also assume that SARS-CoV-2 likely shares similar inflammatory responses. Potential therapeutic tools to reduce SARS-CoV-2-induced inflammatory responses include various methods to block FcR activation. In the absence of a proven clinical FcR blocker, the use of intravenous immunoglobulin to block FcR activation may be a viable option for the urgent treatment of pulmonary inflammation to prevent severe lung injury. Such treatment may also be combined with systemic anti-inflammatory drugs or corticosteroids. However, these strategies, as proposed here, remain to be clinically tested for effectiveness.

The profound deficiency of Th17 cells contributes to HIV disease progression. The mechanisms of their perturbation remain unclear. Recently, CCR6+CD95+CD4+ naive T cells (CCR6+CD95+CD4+ TNA), identified as pre-committed Th17 precursors, were recognized as a subpopulation of CD4+ T cells with stem cell properties. Following phenotypical identification, we evaluated their level in patients during chronic HIV infection and following antiretroviral therapy (ART) using flow cytometry. The levels of CCR6+CD95+CD4+ TNA were decreased during chronic HIV infection and correlated with CD4+ T cell counts. Immunological responders harbored higher frequency of CCR6+CD95+CD4+ TNA, which was associated with CD4/CD8 T cell ratio. Immunological non-responders with lower frequency of CCR6+CD95+CD4+ TNA failed to exhibit a correlation between CCR6+CD95+CD4+ TNA and CCR6+CD95+CD4+ TCM, and displayed elevated ratio of CCR6+CD95+CD4+ TCM/TNA. The number of CCR6+CD95+CD4+ TNA was increased following early ART. These findings shed light on the importance of targeting pre-committed Th17 precursors that enhance immune reconstitution.

Summary HIV-1 infects blood CD4 T cells through the use of CD4 and CXCR4 or CCR5 receptors, which can be targeted through blocking viral binding to CD4/CXCR4/CCR5 or virus-cell fusion. Here we describe a novel mechanism by which HIV-1 nuclear entry can also be blocked through targeting a non-entry receptor, CD2. Cluster of differentiation 2 (CD2) is an adhesion molecule highly expressed on human blood CD4, particularly, memory CD4 T cells. We found that CD2 ligation with its cell-free ligand LFA-3 or anti-CD2 antibodies rendered blood resting CD4 T cells highly resistant to HIV-1 infection. We further demonstrate that mechanistically, CD2 binding initiates competitive signaling leading to cofilin activation and localized actin polymerization around CD2, which spatially inhibits HIV-1-initiated local actin polymerization needed for viral nuclear migration. Our study identifies CD2 as a novel target to block HIV-1 infection of blood resting T cells., Graphical abstract, Highlights • CD2 is highly expressed on human blood CD4 T cells, particularly memory T cells • Prestimulation of CD2 rendered resting T cells highly resistant to HIV infection • CD2 signaling activates cofilin and actin polymerization blocking HIV nuclear entry • CD2 may serve as a novel target to inhibit HIV-1 infection of blood resting T cells, Immune response; Immunology; Virology

Summary Although peripheral B cell dysfunction in early HIV infection is established, how B cell subsets are altered by HIV infection is poorly understood. While investigating B cell subsets among individuals recently infected with HIV, we observe an accumulation of CD27−CD38+ B cells and find that these cells can directly facilitate HIV infection of primary CD4+ T cells in vitro. Comprehensive analyses of the phenotype, function, and transcriptome of the CD27−CD38+ B cell subset is conducted compared with memory and naive B cells. We find that the CD27−CD38+ B cells exhibit a transitional B cell phenotype and an extremely high turnover rate. Importantly, individuals with higher proportions of CD27−CD38+ B cells during early HIV infection tend to become rapid progressors in the chronic infection stage. In this study, we identify a peripheral transitional B cell subset that accumulates during early HIV infection and may contribute to disease progression.

Objective Events occurring during the initial phase of human immunodeficiency virus (HIV) infection are intriguing because of their dramatic impact on the subsequent course of the disease. In particular, the relationship between myeloid-derived suppressor cells (MDSCs) and HIV pathogenesis in primary infection remains unknown and the mechanism of MDSCs in HIV infection are incompletely defined. Methods The frequency of MDSC expression in patients with primary HIV infection (PHI) and chronic HIV infection was measured, and the association with disease progression was studied. Programmed death-ligand 1 (PD-L1) and galectin-9 (Gal-9) expression on MDSCs was measured and in vitro blocking experiments were performed to study the role of PD-L1 in MDSCs' inhibition. Results We found increased levels of HLA-DRCD14CD33CD11b granulocytic(G)-MDSCs in PHI individuals compared with normal controls, which correlated with viral loads and was negatively related to CD4 T-cell levels. When cocultured with purified G-MDSCs, both proliferation and interferon-γ secretion by T cell receptor (TCR)-stimulated CD8 T cells from HIV-infected patients were significantly inhibited. We also demonstrated that PD-L1, but not Gal-9, expression on HLA-DRCD14CD33CD11b cells increased during HIV infection. The suppressive activity of G-MDSCs from HIV-infected patients was attenuated by PD-L1 blockade. Conclusions We found a significant increase in G-MDSCs in PHI patients that was related to disease progression and PD-L1 was used by MDSCs to inhibit CD8 T cells in HIV infection. Our data improve the understanding of HIV pathogenesis in PHI.

Background A small proportion of HIV-infected patients remain clinically and/or immunologically stable for years, including elite controllers (ECs) who have undetectable viremia (10 years). However, the mechanism of nonprogression needs to be further resolved. In this study, a transcriptome meta-analysis was performed on nonprogressor and progressor microarray data to identify differential transcriptome pathways and potential biomarkers. Methods Using the INMEX (integrative meta-analysis of expression data) program, we performed the meta-analysis to identify consistently differentially expressed genes (DEGs) in nonprogressors and further performed functional interpretation (gene ontology analysis and pathway analysis) of the DEGs identified in the meta-analysis. Five microarray datasets (81 cases and 98 controls in total), including whole blood, CD4+ and CD8+ T cells, were collected for meta-analysis. Results We determined that nonprogressors have reduced expression of important interferon-stimulated genes (ISGs), CD38, lymphocyte activation gene 3 (LAG-3) in whole blood, CD4+ and CD8+ T cells. Gene ontology (GO) analysis showed a significant enrichment in DEGs that function in the type I interferon signaling pathway. Upregulated pathways, including the PI3K-Akt signaling pathway in whole blood, cytokine–cytokine receptor interaction in CD4+ T cells and the MAPK signaling pathway in CD8+ T cells, were identified in nonprogressors compared with progressors. In each metabolic functional category, the number of downregulated DEGs was more than the upregulated DEGs, and almost all genes were downregulated DEGs in the oxidative phosphorylation (OXPHOS) and tricarboxylic acid (TCA) cycle in the three types of samples. Conclusions Our transcriptomic meta-analysis provides a comprehensive evaluation of the gene expression profiles in major blood types of nonprogressors, providing new insights in the understanding of HIV pathogenesis and developing strategies to delay HIV disease progression. Electronic supplementary material The online version of this article (doi:10.1186/s12967-017-1294-5) contains supplementary material, which is available to authorized users.

As the first line of defense in the human immune system, NK cells play essential roles in prevention of tumorigenesis and viral infection. It is known that NK cells have impaired function in HIV infection; however, it remains unclear why this occurs. IP-10 is a chemokine and inflammatory factor that is associated with such diseases as tuberculosis, hepatitis B virus, and pancreatic cancer. The aim of this study was to evaluate IP-10 levels and CXCR3 expression in NK cells that were affected by HIV and to elucidate whether NK cell function could be affected by IP-10. Our results demonstrate that IP-10 levels and expression of CXCR3 in NK cells was significantly higher in HIV-infected participants compared with noninfected participants. Moreover, the ability of NK cells to secrete IFN-γ and, specifically, to lyse K562, was suppressed with exposure to high levels of IP-10. This study also showed that CXCR3+ NK cell function decreased dramatically when treated with IP-10, which indicates that CXCR3+ NK cells were the main targets of IP-10. Furthermore, IP-10 or CXCR3 blocking could restore NK cell function. These data suggest that elevated IP-10 levels may impair NK cell function during HIV infection and that IP-10/CXCR3 blocking may be a novel therapeutic strategy in the control and functional cure of HIV.

Introduction IL-21 enhances T and natural killer cells survival and antiviral functions without promoting T cell activation during HIV infection, which makes it a better adjuvant in anti-HIV immunotherapy. Due to the pleiotropy and redundancy of cytokines, it is vital to have a comprehensive knowledge of the role of IL-21 in the regulation of immune responses. Regulatory T cells (Tregs) play an important role in immune regulation and are a determinant of immune therapeutic efficacy in certain circumstances. In this study, we explored the direct effect of IL-21 on Tregs during HIV infection, which has not been addressed before. Methods Thirty-four HIV treatment-naive patients were enrolled and the relationship between CD4 + IL-21 + T cells and Tregs were studied. The effects of IL-21 on CD4 + CD25 + CD127 low Tregs’ apoptosis, proliferation, and CTLA-4 and TGF-β expression in HIV-infected patients was investigated and compared with the effect of other common γ-chain cytokines. Results We found the percentage and absolute numbers of CD4 + IL-21 + T cells were positively related to the frequency or absolute numbers of CD4 + CD25 + or CD4 + CD25 + CD127 low Tregs. Compared with the media-alone control, IL-21, IL-7, and IL-15 could significantly reduce apoptosis of Tregs (p In vitro experiment showed that pretreatment with IL-21 significantly enhanced the suppressive effect of Tregs on CD8+ T cells’ IFN-γ expression. Conclusion We conclude that IL-21 promotes the survival and CTLA-4 expression of Tregs and enhanced the suppressive capacity of Tregs during HIV infection. These results broaden the understanding of HIV pathogenesis and provide critical information for HIV interventions.

Background Natural killer (NK) cells are an important type of effector cell in the innate immune response, and also have a role in regulation of the adaptive immune response. Several studies have indicated that NK cells may influence CD4+ T cells during HIV infection. Methods In total, 51 HIV-infected individuals and 15 healthy controls participated in this study. We performed the flow cytometry assays and real-time PCR for the phenotypic analysis and the functional assays of NK cell-mediated deletion of CD4+ T cells, phosphorylation of nuclear factor-κB (NF-κB/p65) and the intervention of metformin. Results Here we detected high CD54 expression on CD4+ T cells in HIV-infected individuals, and demonstrate that upregulated CD54 is associated with disease progression in individuals infected with HIV. We also show that CD54 expression leads to the deletion of CD4+ T cells by NK cells in vitro, and that this is modulated by NF-κB/p65 signaling. Further, we demonstrate that metformin can suppress CD54 expression on CD4+ T cells by inhibiting NF-κB/p65 phosphorylation. Conclusions Our data suggest that further studies to evaluate the potential role of metformin as adjunctive therapy to reconstitute immune function in HIV-infected individuals are warranted.

Background In human immunodeficiency virus (HIV) infection, 10–15% of individuals exhibit a rapid decline in CD4+ T cells and become rapid progressors (RPs). Overall, understanding the factors affecting rapid disease progression in early HIV infection (EHI) can aid in treatment initiation. Recent studies show that eIF3s, classic scaffold proteins during the translation initiation process, can directly promote or inhibit the translation of mRNA, therefore participating in the regulation of cell function. However, to our knowledge, it has not been addressed whether eIF3s are involved in the diverse prognosis of HIV infection. Methods Expression of eIF3s in primary cells from early or chronic HIV-infected patients was detected by real-time PCR. To investigate the potential mechanisms of eIF3d in the regulation of CD8+ T cell function, complete transcriptomes of eIF3d-inhibited Jurkat T cells were sequenced by RNA sequencing (RNA-Seq). Additionally, to examine the effect of eIF3d on CD8+ T cell function, eIF3d expression was inhibited alone or in combination with SOCS-7 knockdown by siRNA in isolated CD8+ T cells. CD8+ T cell proliferation, IFN-r secretion and apoptosis were detected by flow cytometry. Moreover, the effect of eIF3d on HIV replication was evaluated in Jurkat cells, peripheral blood mononuclear cells (PBMCs) and CD4+ T cells with eIF3d knockdown using a pNL4-3 pseudotyped virus. Results At approximately 100 days of infection, only eIF3d was markedly decreased in RPs compared with chronic progressors (CPs). Expression of eIF3d correlated significantly with disease progression in EHI. Based on in vitro analyses, reduced eIF3d expression led to decreased proliferation and IFN-γ secretion and increased apoptosis in CD8+ T cells. Inhibited expression of eIF3d caused enhanced expression of SOCS-7, and inhibiting SOCS-7 expression by siRNA rescued the attenuated CD8+ T cell function caused by eIF3d. Finally, when eIF3d was inhibited in Jurkat cells, PBMCs and CD4+ T cells, pNL4-3-VSV-G virus replication was enhanced. Conclusions The current data highlight the importance of eIF3d in HIV infection by inhibiting CD8+ T cell function and promoting viral replication. Our study provides potential targets for improved immune intervention. Electronic supplementary material The online version of this article (10.1186/s12967-019-1925-0) contains supplementary material, which is available to authorized users.

A functional HIV cure requires immune reconstitution for lasting viremia control. A major immune dysfunction persisting in HIV infection is the impairment of T helper cell migration and homing to lymphoid tissues such as GALTs (gut-associated lymphoid tissues). ART (antiretroviral therapy) does not fully restore T cell motility for tissue repopulation. The molecular mechanism dictating this persistent T cell dysfunction is not understood. Cofilin is an actin-depolymerizing factor that regulates actin dynamics for T cell migration. Here, we demonstrate that blood CD4 T cells from HIV-infected patients (n = 193), with or without ART, exhibit significantly lower levels of cofilin phosphorylation (hyperactivation) than those from healthy controls (n = 100; ratio, 1.1:2.3; P < 0.001); cofilin hyperactivation is also associated with poor CD4 T cell recovery following ART. These results suggest an HIV-mediated systemic dysregulation of T cell motility that cannot be repaired solely by ART. We further demonstrate that stimulating blood CD4 T cells with an anti-human α4β7 integrin antibody can trigger signal transduction and modulate the cofilin pathway, partially restoring T cell motility in vitro. However, we also observed that severe T cell motility defect caused by high degrees of cofilin hyperactivation was not repairable by the anti-integrin antibody, demonstrating a mechanistic hindrance to restore immune functions in vivo. Our study suggests that cofilin is a key molecule that may need to be therapeutically targeted early for T cell tissue repopulation, immune reconstitution, and immune control of viremia.

Natural killer (NK) cells are important for maintenance of innate immune system stability and serve as a first line of defense against tumors and virus infections; they can act either directly or indirectly and are regulated via co-operation between inhibitory and stimulatory surface receptors. The recently reported inhibitory receptor, TIGIT, can be expressed on the NK cell surface; however, the expression level and function of TIGIT on NK cells during HIV infection is unknown. In this study, for the first time, we investigated the expression and function of TIGIT in NK cells from HIV-infected individuals. Our data demonstrate that the level of TIGIT is higher on NK cells from patients infected with human immunodeficiency virus (HIV) compared with HIV-negative healthy controls. TIGIT expression is inversely correlated with CD4+ T cell counts and positively correlated with plasma viral loads. Additionally, levels of the TIGIT ligand, CD155, were higher on CD4+ T cells from HIV-infected individuals compared with those from healthy controls; however, there was no difference in the level of the activating receptor, CD226, which recognizes the same ligands as TIGIT. Furthermore, TIGIT was found to specifically up-regulated on CD226+ NK cells in HIV-infected individuals, and either rIL-10, or rIL-12 + rIL-15, could induce TIGIT expression on these cells. In addition, high TIGIT expression inhibited the production of interferon-gamma (IFN-γ) by NK cells, while TIGIT inhibition restored IFN-γ production. Overall, these results highlight the important role of TIGIT in NK cell function and suggest a potential new avenue for the development of therapeutic strategies toward a functional cure for HIV.

Background Natural killer (NK) cells play cytotoxic roles by targeting tumor cells or virus infected cells, they also play regulatory roles by secreting cytokines and chemokines. Transforming growth factor (TGF)-β and interleukin (IL)-10 are important immunosuppressive cytokines potentially related to the immune dysregulation that occurs in the infection of human immunodeficiency virus (HIV). NK cells are an important source of TGF-β and a main early producer of IL-10 in response to viral infection. Here, we evaluated the percentages of IL-10+ and TGF-β+ NK cells in HIV-infected patients relative to healthy controls (HCs). Methods Study participants (n = 63) included 31 antiretroviral treatment (ART)-naïve HIV-infected patients, 17 ART-treated HIV-infected patients, and 15 HIV-negative HCs. Expression of IL-10 or TGF-β in NK cells was examined by flow cytometry, and the influences of recombinant IL-10 (rIL-10) or recombinant TGF-β (rTGF-β) on NK cell function were investigated in vitro. Results Compared with HCs, ART-naïve HIV-infected patients had increased percentages of IL-10+ (2.0% vs. 0.4%, p = 0.015) and TGF-β+ (4.5% vs. 2.1%, p = 0.022) NK cells, and ART-treated patients also had a higher percentage of IL-10+ NK cells (2.5% vs. 0.4%, p = 0.002). The percentages of IL-10+ and TGF-β+ NK cells were positively correlated (r = 0.388; p = 0.010). The results of in vitro experiments demonstrated that rIL-10 and rTGF-β inhibited NK cell CD107a expression (p = 0.037 and p = 0.024, respectively), IFN-γ secretion (p = 0.006, p = 0.016, respectively), and granzyme B release after stimulation (p = 0.014, p = 0.040, respectively). Conclusions Our data suggest that the percentages of IL-10+ or TGF-β+ NK cells are increased in HIV-infected patients, and that rIL-10 and/or rTGF-β can inhibit NK cell functions in vitro, providing a potential therapeutic target for strategies aimed at combating HIV infection.

Purpose. To explore the association between differential Tim-3 and PD-1 expression patterns and HIV disease progression, and to investigate the impact of commonγ-chain cytokines on Tim-3 and PD-1 expression patterns on T cells.Methods. Tim-3/PD-1 expression on the T cells of patients with early and chronic HIV infections was detected. The expression levels and functional profiles of T cells with differential Tim-3 and PD-1 expression patterns induced byγ-chain cytokines were studied.Results. The elevation of differential Tim-3 and PD-1 expression patterns on T cells appeared early in HIV infection. Co-expression of Tim-3 and PD-1 (Tim-3+PD-1+) correlates with more severe exhaustion of T cells during HIV infection. In vitro stimulation of commonγ-chain cytokines can induce differential expression patterns of Tim-3 and PD-1 on T cells. The enhancement of Tim-3 and PD-1 expression by commonγ-chain IL-2 can inhibit the function of T cells re-stimulated by HIV gag and TCR, not by the re-stimulation of IL-2.Conclusions. The elevation of differential Tim-3 and PD-1 expression patterns on T cells represents a state of T cell exhaustion and can be induced by commonγ-chain cytokines. These findings provide insights into HIV pathogenesis and help inform immune intervention strategies.

Natural killer (NK) cells are the first line of defense against pathogens of the immune system and also play an important role in resistance against HIV. The activating receptor NKG2C and the inhibitory receptor NKG2A co-modulate the function of NK cells by recognizing the same ligand, HLA-E. However, the role of NKG2A and NKG2C on viral set point and the prediction of HIV disease progression have been rarely reported. In this study, we determined the expression of NKG2C or NKG2A on the surface of NK cells from 22 individuals with primary HIV infection (PHI) stage and 23 HIV-negative normal control (NC) subjects. The CD4+ T cell count and plasma level of HIV RNA in the infected individuals were longitudinally followed-up for about 720 days. The proportion of NKG2C+NKG2A− NK cells was higher in subjects from the low set point group and was negatively correlated with the viral load. In addition, strong anti-HIV activities were observed in NKG2C+ NK cells from the HIV-positive donors. Furthermore, a proportion of NKG2C+NKG2A− NK cells >35.45%, and a ratio of NKG2C/NKG2A >1.7 were predictive for higher CD4+ T cell counts 720 days after infection. Collectively, the experimental results allow us to draw the conclusion that NKG2C+ NK cells might exert an antiviral effect and that the proportion of NKG2C+NKG2A− NK cells, and the ratio of NKG2C/NKG2A, are potential biomarkers for predicting HIV disease progression.

BACKGROUND A substantial percentage (10%–15%) of HIV-infected individuals experience a sharp decline in CD4+ T-cell counts and progress to AIDS quickly after primary infection. Identification of biomarkers distinguishing rapid progressors (RPs) vs chronic progressors (CPs) is critical for early clinical intervention and could provide novel strategies to facilitate vaccine design and immune therapy. METHODS mRNA and microRNA (miRNA) expression profiles in the peripheral blood mononuclear cells (PBMCs) of RPs and CPs were investigated at 111 (22) days [mean (SD)] of HIV infection. The association of mRNA and miRNA expression with disease progression was examined by ROC analysis and Kaplan–Meier survival analysis. RESULTS Pathway enrichment analysis showed that genes with deregulated expression in RPs were primarily involved in apoptosis pathways. Furthermore, we found that 5 miRNAs (miR-31, −200c, −526a, −99a, and −503) in RPs were significantly decreased compared to those in CPs (P < 0.05). The decreased expression of these miRNAs was associated with a rapid disease of progression of HIV infection with a 94% predictive value as measured by the area under the curve. The upregulated predicted targets from the 5 signature miRNAs and all upregulated genes identified from mRNA microarray analysis converged to the apoptosis pathway. Moreover, overexpression of miR-31 in primary human T cells promoted their survival. CONCLUSIONS Our results have identified a distinct transcriptomic signature in PBMCs of RPs and provided novel insights to the pathogenesis of HIV infection.

SummaryThe correct ratio of the HIV-1 structural protein Gag to the envelope protein (Env) is important for maximal virion infectivity. How the virus ensures the production of Gag and Env proteins in an appropriate ratio remains unknown. We report that HIV-1 exploits the host factor RuvB-like 2 (RVB2) to balance relative expression of Gag and Env for efficient production of infectious virions. RVB2 inhibits Gag expression by interacting with both the encoded Matrix (MA) domain of Gag protein and 5′ UTR of the translating mRNA and promoting mRNA degradation in a translation-dependent manner. This inhibitory activity of RVB2 is antagonized by Env through competitive interaction with MA, allowing Gag synthesis to proceed when Env levels are adequate for virion assembly. In HIV-1-positive patients, RVB2 levels positively correlate with viral loads and disease progression status. These findings reveal a mechanism by which HIV-1 regulates its protein expression.

Co-signaling molecules have been demonstrated to regulate regulatory T cells’ (Tregs) function during human immunodeficiency virus (HIV) infection. A recently reported co-signaling molecule called herpes virus entry mediator (HVEM), a member of the tumor necrosis factor receptor family, can both enhance and inhibit the immune response. HVEM was also reported to enhance the suppressive function of regulatory T cells in mice. However, it remains unknown whether HVEM can regulate Treg function in HIV-infected patients or whether HVEM affects HIV disease progression. In this study, we found that the blockage of the HVEM could weaken Tregs’ suppressive activity to effector T cells (Teffs). HVEM expression is reduced during the asymptomatic phase of HIV infection and fairly predictive of the recovery of CD4+T-cells in response to highly active anti-retroviral therapy (HAART), more so than nadir CD4+T-cell count or viral load. Taken together, these findings demonstrate the importance of HVEM in relation to Treg function and HIV disease progression, which would have therapeutic implications and provide insight into the pathogenesis of acquired immune deficiency syndrome (AIDS).

CD3+CD56+NKT-like cells are one of the critical effectors in the immune response to viral infection and tumors, but the functional features of NKT-like cells in HIV infection have been rarely reported. In this study, we observed and described the state of NKT-like cell functions in primary HIV-infected individuals (PHIs), chronic HIV-infected individuals (CHIs), long-term nonprogressors (LTNPs), and HIV-negative controls (NCs). The results showed that the percentage of IFN-γ+CD3+CD56+NKT-like cells was notably higher in LTNPs compared with CHIs, and the proportion of CD3+CD56+NKT-like cells with dual function (IFN-γ+CD107a+NKT-like cells) in LTNPs was also much higher than in CHIs. Additionally, the percentages of IFN-γ+CD107a+NKT-like cells negatively correlated with viral load. Taken together, our data demonstrated that good functions of CD3+CD56+NKT-like cells in LTNPs likely occurred as a protective mechanism that slows down HIV disease progression.