Biology subjects

Ouchi, D.

Publications and source records attributed to Ouchi, D..

3 recordsLinked to original sources

bioRxiv2024

PD-1 blockade enhances HIV-1 vaccine-induced CD8+ T-cell responses in PWH early ART-treated

Current HIV-1 therapeutic vaccines do not generate T-cell immune responses in people with HIV-1 (PWH) able to eradicate the virus or to broadly control viral replication. The expression of inhibitory receptors (IRs) may limit vaccine efficacy by reducing specific effector functions in vaccine-induced T-cells. Recently, the clinical use of antibodies targeting IRs or immune checkpoint blockade (ICB) has demonstrated remarkable success in cancer remission. Therefore, there is a potential benefit of using ICB in PWH to improve the effectiveness of vaccine-induced T-cell responses. Here, we evaluated functional changes in vaccine-induced HIV-specific CD8 T-cell responses by in-vitro PD-1 and TIM-3 blockade during immune stimulation in PWH early ART-treated and vaccinated (Etvac). We compared Etvac to PWH early ART-treated (Et) and chronic ART-treated PWH (Chro). Our results demonstrate a significant increase in the functional responses of vaccine-induced HIV-1-specific CD8 T-cells upon PD-1 but not TIM-3 blockade in cellular proliferation, IFN{gamma} production, and activation. Although no effect was found in Et, similar findings were obtained in HIV-1-specific CD8 T-cells in Chro for combined PD-1/TIM-3 blockade. Moreover, we identify in Etvac a direct association between PD-1 expression in CD8+ T cells and in vitro response to anti-PD-1 treatment. Our findings support the potential adjuvant effect of PD-1 blockade to improve HIV-1 therapeutic vaccine efficacy in early ART-treated PWH for future human studies.

immunology↗

bioRxiv2022

Single-cell CD8+ dynamics in PLWH uncover the depletion of TIGIT+ memory HIV-1-specific cells during long-term ART

The co-expression of inhibitory receptors (IRs) is a hallmark of CD8+ T-cell exhaustion (Tex) in people living with HIV-1 (PLWH). Understanding alterations of IRs expression in PLWH on long-term antiretroviral treatment (ART) remains elusive but is critical to overcoming CD8+ Tex and designing novel HIV-1 cure immunotherapies. To address this, we combine high-dimensional supervised and unsupervised analysis of IRs concomitant with functional markers across the CD8+ T-cell landscape on 24 PLWH over a decade on ART. We define irreversible alterations of IRs co-expression patterns in CD8+ T cells not mitigated by ART and identify negative associations between the frequency of TIGIT+ and TIGIT+TIM-3+ and CD4+ T-cell levels. Moreover, changes in total, SEB-activated, and HIV-1-specific CD8+ T-cells delineate a complex reshaping of memory and effector-like cellular clusters on ART. Indeed, we identify a selective reduction of HIV-1 specific-CD8+ T-cell memory-like clusters sharing TIGIT expression and low CD107a that can be recovered by mAb TIGIT blockade independently of IFN{gamma} and IL-2. Collectively, these data characterize with unprecedented detail the patterns of IRs expression and functions across the CD8+ T-cell landscape and indicate the potential of TIGIT as a target for Tex precision immunotherapies in PLWH at all ART stages.

immunology↗

bioRxiv2021

Highly functional Cellular Immunity in SARS-CoV-2 Non-Seroconvertors is associated with immune protection

The role of T cells in the control of SARS-CoV-2 infection has been underestimated in favor of neutralizing antibodies. However, cellular immunity is essential for long-term viral control and protection from disease severity. To understand T-cell immunity in the absence of antibody generation we focused on a group of SARS-CoV-2 Non-Seroconvertors (NSC) recovered from infection. We performed an immune comparative analysis of SARS-CoV-2 infected individuals stratified by the absence or presence of seroconversion and disease severity. We report high levels of total naive and low effector CD8+ T cells in NSC. Moreover, polyfunctional Nucleocapsid (NP)-specific CD8+ T-cell responses, as well as reduced levels of T-cell activation monitored by PD-1 and activation-induced markers, were distinctive immunological traits in NSC. Longitudinal data support the stability of the NSC phenotype over three months. Our results implicate highly functional SARS-CoV-2 Spike and NP T-cell responses with low immune activation in protection from disease severity in the absence of seroconversion. SUMMARYTo understand SARS-CoV-2 specific T-cell immunity in the absence of seroconversion, we characterized immunological features of Non-Seroconvertors recovered from infection. Highly functional specific T-cell responses and low immune activation were determinants of immune protection from severe disease.

immunology↗