CD4 and HIV-1 infection: At this point, HIV-1 infection resulted in a trend toward suppression of Toll-like receptor 3 (TLR3) protein expression on splenic but not peripheral CD4 T cells, whereas peripheral TLR7 and TLR9 protein expression was elevated after HIV-1 infection of both CD4 T cells and macrophages (Fig. 4b, c, e, and f).