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TIGIT expression on natural killer (NK) cells is associated with dysfunction during chronic HIV infection, but the phenotype and biological functions of these cells in the context of acute HIV-1 infection remain poorly understood. Here, 19 acutely infected HIV-1 patients traced at first, third and twelfth month, and age-matched patients with chronic HIV-1 infection were enrolled to investigate the phenotype and functions of TIGIT expression on NK cells. We found that TIGIT-expressing NK cells did not increase in frequency in the first, third and twelfth month of infection until chronic HIV-1 infection lasted over 2 years. The number of TIGIT+NK cells in acute infection was positively associated with HIV-1 viral load (r = 0.53, P = 0.0009). CD96 was significantly upregulated on NK cells after acute infection for 1 month and in chronic infection over 2 years, while CD226 was downregulated in chronic infection over 2 years. Further, at different stages of infection, CD96−CD226+ cells diminished among total NK cells, TIGIT+NK and TIGIT−NK cells, while CD96+CD226− cells expanded. Reduced CD96−CD226+ cells and elevated CD96+CD226− cells among NK cells especially TIGIT−NK cells, had opposite associations with viral load in the first month of infection, as well as CD4 T-cell counts in including the twelfth month and more than 2 years of chronic infection. In both HIV-1-infected individuals and healthy donors, TIGIT was predominantly expressed in NKG2A−NKG2C+NK cells, with a significantly higher proportion than in NKG2A+NKG2C−NK cells. Moreover, the frequencies of TIGIT+NK cells were positively associated with the frequencies of NKG2A−NKG2C+NK cells in acute infection (r = 0.62, P < 0.0001), chronic infection (r = 0.37, P = 0.023) and healthy donors (r = 0.36, P = 0.020). Enhanced early activation and coexpression of CD38 and HLA-DR in TIGIT+NK cells were detected compared to TIGIT−NK cells, both of which were inversely associated with the decrease in CD4 T-cell counts in both acute and chronic HIV-1 infection. The ability of TIGIT+NK cells to produce TNF-α, IFN-γ and CD107a degranulation substance were consistently weaker than that of TIGIT−NK cells in both acute and chronic infection. Moreover, the functionalities of TIGIT+NK cells were lower than those of TIGIT−NK cells, except for TNF-α−CD107a+IFN-γ−NK cells. These findings highlight the phenotype and functional characteristics of TIGIT-expressing NK cells which have poor capabilities in inhibiting HIV-1 replication and maintaining CD4 T-cell counts. [ABSTRACT FROM AUTHOR]

The efficacy of dendritic cell (DC)-based cancer vaccines is critically determined by the functionalities of in vitro maturated DCs. The maturation of DCs typically relies on chemicals that are cytotoxic or hinder the ability of DCs to efficiently activate the antigen-specific cytotoxic T-lymphocytes (CTLs) against tumors. Herein, the maturation chemicals are replaced with extracellular silica nanomatrices, fabricated by glancing angle deposition, to promote in vitro maturation of murine bone marrow-derived DCs (mBMDCs). The extracellular nanomatrices composed of silica nanozigzags (NZs) enable the generation of mature mBMDCs with upregulated levels of co-stimulatory molecules, C-C chemokine receptor type-7, X-C motif chemokine recetpor-1, DC-specific ICAM-3 grabbing nonintegrin, and enhanced endocytic capacity. The in vitro maturation is partially governed by focal adhesion kinase (FAK) that is mechanically activated in the curved cell adhesions formed at the DC-NZ interfaces. The NZ-maturated mBMDCs can prime the antigen-specific CTLs into programmed cell death protein-1 (PD-1) low CD44 high memory phenotypes in vitro and suppress the growth of tumors in vivo. Meanwhile, the NZ-mediated beneficial effects are also observed in human monocyte-derived DCs. This work demonstrates that the silica NZs promote the anti-tumor capacity of in vitro maturated DCs via the mechanoactivation of FAK, supporting the potential of silica NZs being a promising biomaterial for cancer immunotherapy., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

The dysfunction of memory CD8 + T cell cannot be reverted by successful clearance of hepatitis C virus (HCV) after direct-acting antivirals (DAAs) therapy, increasing the risk of reinfection with HCV. Stem cell-like memory T cells (Tscm) with superior properties of long-lasting, self-renewing, and multipotency contribute to the maintenance of immune function. We investigated the impact of HCV infection on CD8 + Tscm, and their possible role in disease progression, by using DAA-naive HCV-infected and human immunodeficiency virus (HIV)/HCV-coinfected cohorts. The distribution of memory CD8 + T cell subsets and the level of T cell immune activation were determined by flow cytometry. Associations between CD8 + Tscm and other memory T cell subsets, HCV viral load, as well as the level of T cell immune activation were analyzed. We observed that the proportion of CD8 + Tscm increased in both HCV and HIV/HCV individuals. The proportion of CD8 + Tscm had positive and negative correlation with CD8 + Tcm (central memory T cells) and CD8 + Tem (effector memory T cell), respectively, representing the contribution of CD8 + Tscm in T cell homeostasis. In addition, higher frequency of CD8 + Tscm indicated lower HCV viral load and less T cell immune activation in HCV infection, which suggested that CD8 + Tscm is likely associated with effective control of HCV replication for protective immunity. Considering the characteristics of Tscm, our current findings provide implications for Tscm-based vaccine design and immunotherapy development to achieve HCV elimination.

TIGIT expression on natural killer (NK) cells is associated with dysfunction during chronic HIV infection, but the phenotype and biological functions of these cells in the context of acute HIV-1 infection remain poorly understood. Here, 19 acutely infected HIV-1 patients traced at first, third and twelfth month, and age-matched patients with chronic HIV-1 infection were enrolled to investigate the phenotype and functions of TIGIT expression on NK cells. We found that TIGIT-expressing NK cells did not increase in frequency in the first, third and twelfth month of infection until chronic HIV-1 infection lasted over 2 years. The number of TIGIT + NK cells in acute infection was positively associated with HIV-1 viral load ( r = 0.53, P = 0.0009). CD96 was significantly upregulated on NK cells after acute infection for 1 month and in chronic infection over 2 years, while CD226 was downregulated in chronic infection over 2 years. Further, at different stages of infection, CD96 - CD226 + cells diminished among total NK cells, TIGIT + NK and TIGIT - NK cells, while CD96 + CD226 - cells expanded. Reduced CD96 - CD226 + cells and elevated CD96 + CD226 - cells among NK cells especially TIGIT - NK cells, had opposite associations with viral load in the first month of infection, as well as CD4 T-cell counts in including the twelfth month and more than 2 years of chronic infection. In both HIV-1-infected individuals and healthy donors, TIGIT was predominantly expressed in NKG2A - NKG2C + NK cells, with a significantly higher proportion than in NKG2A + NKG2C - NK cells. Moreover, the frequencies of TIGIT + NK cells were positively associated with the frequencies of NKG2A - NKG2C + NK cells in acute infection ( r = 0.62, P < 0.0001), chronic infection ( r = 0.37, P = 0.023) and healthy donors ( r = 0.36, P = 0.020). Enhanced early activation and coexpression of CD38 and HLA-DR in TIGIT + NK cells were detected compared to TIGIT - NK cells, both of which were inversely associated with the decrease in CD4 T-cell counts in both acute and chronic HIV-1 infection. The ability of TIGIT + NK cells to produce TNF-α, IFN-γ and CD107a degranulation substance were consistently weaker than that of TIGIT - NK cells in both acute and chronic infection. Moreover, the functionalities of TIGIT + NK cells were lower than those of TIGIT - NK cells, except for TNF-α - CD107a + IFN-γ - NK cells. These findings highlight the phenotype and functional characteristics of TIGIT-expressing NK cells which have poor capabilities in inhibiting HIV-1 replication and maintaining CD4 T-cell counts., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zhang, Lu, Cheung, Zhang, Liu, Li, Yuan, Wang, Liu, Tang, Xia, Wu, Zhang and Su.)

Individuals who have been preinfected by human cytomegalovirus (HCMV) are more prone to AIDS disease progression after subsequent HIV-1 infection but the underlying mechanism remains elusive. HCMV is a ubiquitous DNA virus that commonly establishes lifelong latent infection in CD34 + progenitor cells, where latency-specific HCMV genes may modulate host restriction to HIV-1 infection. To test this hypothesis, we studied progenitor cells that are known to resist replicative HIV-1 infection because of the intrinsic expression of host restriction factors. Interestingly, in primary CD34 + cells undergoing latent HCMV infection, an enhanced level of HIV-1 proviral DNA and replication was observed as measured by digital polymerase chain reaction, quantitative polymerase chain reaction, and Gag expression, and confirmed using dual-reporter pseudovirus encoding X4- or R5-tropic envelope and T-cell transfer. This phenomenon may be partially explained by the upregulation of HIV-1 entry coreceptors, including chemokine receptors CXCR4 and CCR5, but not of the primary receptor CD4. Furthermore, latent HCMV infection downregulated the expression of HIV-1 restriction factors SAMHD1, APOBEC3G, tetherin, and Mx2 in CD34 + progenitor cells, which may confer to enhanced HIV-1 infection. However, this enhancement was abrogated when ultraviolet-inactivated HCMV was used for comparison, suggesting that expression of latent HCMV genes is essential for this effect. Importantly, HCMV gB and HIV-1 p24 can be detected in the same cell by immunofluorescence and flow cytometry; therefore, the establishment of HCMV latency in CD34 + cells likely leads to host cell gene modulation that favors HIV-1 infection., Competing Interests: Conflict-of-interest disclosure: The authors declare no competing financial interests.