CD44 and HIV-1 infection: Restriction factors are as follows: RAD51 interacts with HIV-1 integrase (IN) and inhibits its activity [28]; the transcription factor GATA1 effectively inhibits the expression of the HIV-1 co-receptor CCR5 in human T cells and dendritic cells [25]; additionally, the significant increases in IRF4 mRNA levels are associated with T cell immune activation and represent a potential target for delaying HIV-1 infection [29].