Comparison of susceptibility to SIVmac239 infection between CD4⁺ and CD4⁺8⁺ T cells

Summary.

CD4-bearing T cells are the primary targets for human immunodeficiency virus type 1(HIV-1)/simian immunodeficiency virus (SIV) infection. However, it is unclear whether the susceptibility of CD4-bearing T cells including CD4 single positive and CD4/8 double positive T cells to HIV/SIV infection is the same or not. In this study, we compared the susceptibility to SIV infection between CD4⁺ and CD4⁺8⁺ T cells, using Herpesvirus saimiri (HVS)-transformed CD4⁺ and CD4⁺8⁺ T cells established from peripheral blood mononuclear cells (PBMC) of rhesus macaques. Although there was little difference between the two CD4-bearing T cell population in the expression level of CD4 molecules and chemokine receptors such as CXCR4 and CCR5, SIV replicated more efficiently in CD4⁺8⁺ T cells than in CD4⁺ T cells. Moreover, we found that reverse transcription initiated more efficiently in CD4⁺8⁺ T cells than in CD4⁺ T cells and that the cell lysates from CD4⁺ T cells impaired the RT activity more strongly than that from CD4⁺8⁺ T cells. These findings suggest that intracellular environment in CD4⁺ 8⁺ T cells is better for reverse transcription and that the infection of those CD4⁺8⁺ T cells might play critical and different roles in HIV-1/SIV infection and dissemination.