Evaluation of the effect of pim6 on the induction of hiv-1 expression from memory cd4+ t cells of virally suppressed hiv-1 patients attending TASO clinic, Mulago.
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Background: Latent HIV-1 reservoirs harbour human immunodeficiency virus type 1 (HIV-1) proviral DNA which can be reactivated to express viral RNA. Memory CD4+ T cells in HIV-infected persons are critical as HIV reservoirs, as combinational antiretroviral therapy (cART) effectively controls HIV replication as detected in plasma; however, the virus persists, mostly as latent infection in memory CD4+ T cells, with marginal decay despite prolonged cART. While understanding of HIV-1 reactivation from memory CD4+ T cell reservoirs is focused on treatment of in vitro latently infected T cells with chemical latency reversing agents (LRAs), limited information is available on use of biological molecules such as Mycobacterium tuberculosis (M.tb), the most common infection during HIV-1 co-infections in Uganda. Mtb particularly its cell wall lipoglycan, PIM6 has been demonstrated to induce transcription of HIV-1 proviral DNA from in vitro latently infected memory (m) CD4+ T cells (13). However, its effect on the mCD4+T cell viability, activation, induction of HIV-1 expression from naturally infected mCD4+T cells from HIV-1 infected individuals was not determined. Therefore, this study aimed at evaluating the effect of PIM6 on induction of HIV-1 expression from mCD4+T cells of virally suppressed HIV-1 infected subjects attending TASO clinic, Mulago. Objectives: 1) To determine the effect of PIM6 on viability and activation of memory CD4+ T cells of virally suppressed HIV infected individuals. 2) To determine if PIM6 induces HIV-1 expression from memory CD4+ T cells of virally suppressed HIV-1 infected individuals. Methods: We conducted a cross-sectional study in which we recruited 24 virally suppressed HIV-1 infected individuals. Memory CD4+ T cells were isolated from whole blood samples obtained from virally suppressed HIV-1 infected individuals. Viability of mCD4+cells, expression of activation marker CD25, and HIV-1 RNA expression from mCD4+T cells were determined by flow cytometry and qPCR assay, respectively, after 72 hours of co-culture with PIM6. Non-parametric analysis using the Kruskal-Wallis test / Mann-Whitney U test was done to determine the effect of PIM6 on viability, CD25 expression and HIV-1 RNA levels. Results: The viability of PIM6-treated mCD4+ T cells ranged from 95 to 99%, indicating that PIM6 does not induce mCD4+ T cell death. There was no significant increase in the expression of T cell activation marker CD25 on PIM6 treated mCD4+T cells compared to the MOCK (untreated control) (P = 0.05031). PIM6 significantly induced HIV-1 expression from some mCD4+ T cells of HIV-1 subjects on suppressive cART compared to the MOCK (P= 0.0471). The level of PIM6-induced HIV-1 expression was similar to that induced by conA (positive control) (p=0.7221). Conclusion: Mycobacterial component PIM6 does not affect viability of mCD4+ T cells, and does not induce expression of activation marker CD 25 on mCD4+ T cells of virally suppressed HIV-1 subjects. However, it induces significant HIV-1 expression from naturally infected mCD4+T cells. Recommendation: There is need for further studies to understand the in vivo relevance of Mtb PIM6-induced HIV-1 expression in HIV/TB co-infected individuals.