Susceptibility of two CD4(-)T cell lines to HIV and SIV infection

It is well established that CD4 is the main receptor for both HIV and SIV v iruses and it has been proposed that a CD4-induced change in gp120 conforma tion is necessary for a correct binding to the chemokine receptors. In fact , in the absence of CD4, the V3 loop is not correctly exposed to allow the direct binding of gp120 to chemokine receptors (2). Recent studies have als o shown that some variants of HIV-1 and HIV-2 cultured in the laboratory ca n infect both lymphoid and nonlymphoid cells in the absence of CD4 indicati ng that these viruses can utilize coreceptor without a prior CD4 interactio n. To gain some insights into the pathogenesis of AIDS and to elucidate the capability of HIV and SIV viruses to infect cells of different compartment s, we studied the susceptibility to HIV and SIV infection of two human CD4( -) T cell line.