CD4 and HIV infectious disease: More recently, it was observed that Tetanus toxoid and C. albicans specific CD4+ T cells with a Th17 profile (and high expression of CCR6 and its CCL20 ligand) were permissive to HIV infection, whereas CMV-specific CD4+ T cells with a Th17 profile were highly resistant to both R5 and X4 HIV strains [121].