CXCR5 and HIV infectious disease: By contrast, because B-cell follicle-residing TFH cells are major virus producers compared to other CD4 T cell types in the T cell zone in HIV infection (24, 120), it is reasonable to infer that HIV-specific CXCR5+CD8 T cells, but not CXCR5−CD8 T cells, have chances to come into contact with and kill these target cells.