The CD4+ Tfh subset is dedicated to helping B cell and is essential to the maturation of high affinity antibodies. We are investigating whether the high avidity TCRs characteristic of HIV Controller CD4+ T cells may confer an efficient Tfh differentiation. We will compare the B cell helper function of HIV-specific CD4+ T cells from Controllers and treated patients. We will then compare the T helper differentiation patterns conferred by high- and low-avidity HIV-specific TCRs after in vitro transfer to heterologous CD4+ T cells. The general objective will be to achieve an efficient CD4+ T cell/ B cell coculture system for the in vitro production of highly matured antibodies directed against HIV.