SAMHD1 and HIV-1 infection: Recent studies in T cells infected with HIV-1 have indicated the role of restriction factors like APOBEC3G (apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3G), Tetherin (CD317), SAMHD1 (SAM domain and HD domain-containing protein 1), and TRIM5α (Tripartite motif-containing protein 5,) in the front-line defense against HIV-1 infection.