Since TRIM5α restricts the replication of retroviruses by interfering with a post-entry step in their life cycle, we chose first to evaluate the effect of specific TRIM5 allelic products by assessing the in vitro susceptibility of rhesus monkey B-lymphoblastoid cell lines (B-LCLs) expressing defined TRIM5 alleles to infection with a vesicular stomatitis virus G (VSV-G)-pseudotyped SIVmac239-GFP construct. This evidence concerns the gene TRIM5 and infection.