Lysis of primary infected CD4 T cells by ADCC

BIEDMA, M.E; DECOVILLE, T; HOLL, V; PERESSIN, M; LAMBOTIN, M; SU, B; LAUMOND, G; SCHMIDT, S; PROUST, A; MOOG, C

Encuentro; Journées Scientifiques de la Fédération de Médecine Translationnelle de Strasbourg; 2013

Increasing evidence support a role of inhibitory activities beyond neutralization in the control of HIV-1 infection by antibodies (Abs). Protection obtained on RV144 vaccination trial has been related to non-neutralizing activity. Among non-neutralizing inhibitory activities, antibody-dependent cellular cytotoxicity (ADCC) has been proposed as a possible mechanism of protection. These ADCC activities were mainly assessed by detection of lysis of cell lines, either infected or loaded with recombinant Env proteins, by Natural Killer (NK) cells. In order to analyze ADCC in more physiological conditions, assays measuring the lysis of primary infected CD4 T-cells in the presence of autologous NK cells were performed on a panel of monoclonal and polyclonal HIV-specific Ab activities.NK cells and CD4 T-cells were purified from PBMC of HIV-negative donors by magnetic positive selection. Activated lymphocytes were infected with various primary isolates and autologous NK cells were added for 4 hours in the presence of different concentrations of Abs. The percentage of HIV-1-infected CD4 T-cells was detected by flow cytometry and lysis of infected cells was calculated in presence of antibodies.We found that NK cells lyse HIV-1 infected cells in the presence of various HIVspecific antibodies (neutralizing or non-neutralizing mAbs, different polyclonal samples). Interestingly, the activity varied according to the primary isolate tested and the inhibitory profile of Ab was distinct to that previously describes with ADCC assays involving cell lines. The ADCC activity detected under these experimental conditions reinforce the possible role of such activity in HIV-1 inhibition in vivo. Comparison between current available ADCC assays is required before validation, standardization and analysis of correlates of protection.