Antiviral activity correlates with the phenotype and polyfunctionality of stimulated CD8+ T-cells from HIV+ subjects who initiated cART at different time points after acute infection

SALIDO, J; FIGUEROA, ME; SUED, O; RUIZ, MJ; GHIGLIONE, Y; CARUSO, MP; SALOMÓN, H; TURK, G; TRIFONE, C; GHERARDI, MM; LAUFER, N

Congreso; The 22nd International AIDS Conference (AIDS 2018), Amsterdam, the Netherlands; 2018

Background: HIV functional cure will largely depend on the capacity(natural or artificially modulated) of CD8+ T-cells (CD8TCs) to eliminateremaining infected cells, despite effective cART.Aim: to evaluate the antiviral capacity of expanded HIV-specific CD8TCs,from HIV+ subjects with different timing of cART initiation after the acutephase of infection.Methods: PBMCs from 25 HIV+ subjects on cART for 1 year were obtained.Twelve initiated treatment during chronic infection (DelayedTreatment, DT) and 13 within four months post-infection (Early Treatment,ET). PBMCs were stimulated with peptides pools spanning Nef and Gagproteins during 14 days. CD8TC phenotype (CD45RO, CCR7, CD95 andPD1 expression) and function (CD107a/b, IFNγ, IL-2, MIP-1β and TNFα) wereanalyzed by flow cytometry post-expansion. Direct and indirect antiviralactivity of expanded CD8TCs against autologous CD4TCs was evaluatedby VITAL Assay (VA) and Viral Inhibition Assay (VIA), respectively. Nonparametricstatistics were applied.Results: HIV-specific CD8TCs showed a homogenous distribution ofmono-, bi-, tri-, tetra- and pentafunctional cells in DT, while ET showeda higher proportion of monofunctional cells. A preservation of bulkand HIV-specific memory stem-cell (CD8TCSCM) and central memory(CD8TCCM) subsets was observed on ET. Contrary, DT showed a fullydifferentiatedprofile (p< 0.005). Despite these, expanded CD8TCs fromboth groups equally mediated antiviral activity, evaluated either by VIAor VA. Nef-specific CD8TCs showed a higher magnitude of VIA and VAcompared to p24-specific cells. VIA inversely correlated with both bulk(p=0.0438) and HIV-specific (p=0.0323) CD8TCSCM and with monofunctionalcells (p=0.0235). Instead, VA magnitude directly correlated with theproportion of bulk terminal effectors CD8TCs (p=0.0402), inversely withbulk CD8TCSCM (p=0.0137) as well as directly with %CD107+ (p=0.0257),IFNγ+ (p=0.0373), TNFα+ (p=0.0155) and tri- (p=0.025) and tetrafunctional(p=0.0278) CD8TCs able to degranulate and express IFNγ simultaneously.Conclusions: Different cART initiation timing affected CD8TCs phenotypeand polyfunctionality. However, it did not afffect direct and indirectantiviral activities. VIA magnitude correlated with CD8TC memory/effectordifferentiation profile, while VA was also associated with polyfunctionality,particularly with degranulation capacity. Overall, Nef emergedas an interesting candidate for therapeutic formulations aimed to modulateHIV-specific CD8TCs response since Nef-specific cells showed thebest performance in our model.