Transforming Growth Factor ß Signaling Promotes HIV-1 Infection in Activated and Resting Memory CD4+ T Cells.

Understanding the facilitator of HIV-1 infection and subsequent latency establishment may aid the discovery of potential therapeutic targets. Here, we report the elevation of plasma transforming growth factor ß (TGF-ß) during acute HIV-1 infection among men who have sex with men (MSM). Using a serum-free in vitro system, we further delineated the role of TGF-ß signaling in mediating HIV-1 infection of activated and resting memory CD4+ T cells. TGF-ß could upregulate both the frequency and expression of the HIV-1 coreceptor CCR5, thereby augmenting CCR5-tropic viral infection of resting and activated memory CD4+ T cells via Smad3 activation. The production of live HIV-1JR-FL upon infection and reactivation was increased in TGF-ß-treated resting memory CD4+ T cells without increasing CD4 expression or inducing T cell activation. The expression of CCR7, a central memory T cell marker that serves as a chemokine receptor to facilitate T cell trafficking into lymphoid organs, was also elevated on TGF-ß-treated resting and activated memory CD4+ T cells. Moreover, the expression of CXCR3, a chemokine receptor recently reported to facilitate CCR5-tropic HIV-1 infection, was increased on resting and activated memory CD4+ T cells upon TGF-ß treatment. These findings were coherent with the observation that ex vivo CCR5 and CXCR3 expression on total resting and resting memory CD4+ T cells in combination antiretroviral therapy (cART)-naive and cART-treated patients were higher than in healthy individuals. Overall, the study demonstrated that TGF-ß upregulation induced by acute HIV-1 infection might promote latency reservoir establishment by increasing infected resting memory CD4+ T cells and lymphoid organ homing of infected central memory CD4+ T cells. Therefore, TGF-ß blockade may serve as a potential supplementary regimen for HIV-1 functional cure by reducing viral latency. IMPORTANCE Incomplete eradication of HIV-1 latency reservoirs remains the major hurdle in achieving a complete HIV/AIDS cure. Dissecting the facilitator of latency reservoir establishment may aid the discovery of druggable targets for HIV-1 cure. This study showed that the T cell immunomodulatory cytokine TGF-ß was upregulated during the acute phase of infection. Using an in vitro serum-free system, we specifically delineated that TGF-ß promoted HIV-1 infection of both resting and activated memory CD4+ T cells via the induction of host CCR5 coreceptor. Moreover, TGF-ß-upregulated CCR7 or CXCR3 might promote HIV-1 latent infection by facilitating lymphoid homing or IP-10-mediated viral entry and DNA integration, respectively. Infected resting and central memory CD4+ T cells are important latency reservoirs. Increased infection of these cells mediated by TGF-ß will promote latency reservoir establishment during early infection. This study, therefore, highlighted the potential use of TGF-ß blockade as a supplementary regimen with cART in acute patients to reduce viral latency.

Characterisation of a Hepatitis C Virus Subtype 2a Cluster in Scottish PWID with a Suboptimal Response to Glecaprevir/Pibrentasvir Treatment.

Direct-acting antivirals (DAAs) have revolutionised the treatment of Hepatitis C virus (HCV), allowing the World Health Organisation (WHO) to set a target of eliminating HCV by 2030. In this study we aimed to investigate glecaprevir and pibrentasvir (GP) treatment outcomes in a cohort of patients with genotype 2a infection. METHODS: Clinical data and plasma samples were collected in NHS Greater Glasgow & Clyde. Next generation whole genome sequencing and replicon assays were carried out at the MRC-University of Glasgow Centre for Virus Research. RESULTS: 132 cases infected with genotype 2a HCV were identified. The SVR rate for this group was 91% (112/123) following treatment with GP. An NS5A polymorphism, L31M, was detected in all cases of g2a infection, and L31M+R353K in individuals that failed treatment. The results showed that R353K was present in 90% of individuals in the Glasgow genotype 2a phylogenetic cluster but in less than 5% of all HCV subtype 2a published sequences. In vitro efficacy of pibrentasvir against sub-genomic replicon constructs containing these mutations showed a 2-fold increase in IC50 compared to wildtype. CONCLUSION: This study describes a cluster of HCV genotype 2a infection associated with a lower-than-expected SVR rate following GP treatment in association with the NS5A mutations L31M+R353K.