[HTML][HTML] Perturbed CD8+ T cell TIGIT/CD226/PVR axis despite early initiation of antiretroviral treatment in HIV infected individuals

J Tauriainen, L Scharf, J Frederiksen, A Naji… - Scientific reports, 2017 - nature.com
J Tauriainen, L Scharf, J Frederiksen, A Naji, HG Ljunggren, A Sönnerborg, O Lund
Scientific reports, 2017nature.com
Abstract HIV-specific CD8+ T cells demonstrate an exhausted phenotype associated with
increased expression of inhibitory receptors, decreased functional capacity, and a skewed
transcriptional profile, which are only partially restored by antiretroviral treatment (ART).
Expression levels of the inhibitory receptor, T cell immunoglobulin and ITIM domain (TIGIT),
the co-stimulatory receptor CD226 and their ligand PVR are altered in viral infections and
cancer. However, the extent to which the TIGIT/CD226/PVR-axis is affected by HIV-infection …
Abstract
HIV-specific CD8+ T cells demonstrate an exhausted phenotype associated with increased expression of inhibitory receptors, decreased functional capacity, and a skewed transcriptional profile, which are only partially restored by antiretroviral treatment (ART). Expression levels of the inhibitory receptor, T cell immunoglobulin and ITIM domain (TIGIT), the co-stimulatory receptor CD226 and their ligand PVR are altered in viral infections and cancer. However, the extent to which the TIGIT/CD226/PVR-axis is affected by HIV-infection has not been characterized. Here, we report that TIGIT expression increased over time despite early initiation of ART. HIV-specific CD8+ T cells were almost exclusively TIGIT+, had an inverse expression of the transcription factors T-bet and Eomes and co-expressed PD-1, CD160 and 2B4. HIV-specific TIGIThi cells were negatively correlated with polyfunctionality and displayed a diminished expression of CD226. Furthermore, expression of PVR was increased on CD4+ T cells, especially T follicular helper (Tfh) cells, in HIV-infected lymph nodes. These results depict a skewing of the TIGIT/CD226 axis from CD226 co-stimulation towards TIGIT-mediated inhibition of CD8+ T cells, despite early ART. These findings highlight the importance of the TIGIT/CD226/PVR axis as an immune checkpoint barrier that could hinder future “cure” strategies requiring potent HIV-specific CD8+ T cells.
nature.com