Mutations in CCR5-coding sequences are not associated with SIV carrier status in African nonhuman primates

African monkeys can be naturally infected with SIV but do not progress to A IDS. Since mutations in the human CCR5 gene have been shown to influence su sceptibility to HIV infection and disease progression, we have now investig ated whether mutations in CCR5-coding sequences in African nonhuman primate s can explain species-specific differences in susceptibility to lentiviral infection, The animals studied comprise chronically infected monkeys corres ponding to four natural hosts of SIV (Cercopithecus aethiops, Cercopithecus pygerythrus, Cercopithecus sabaeus, and Cercopithecus tantalus), noninfect ed animals from three species that are known to be susceptible to SIV infec tion (Cercopithecus patas, Cercopithecus lhoesti, and Pan troglodytes), and monkeys of six species that do not carry SIV in the wild (Cercocebus galer itus, Cercocebus aterrimus, Cercopithecus ascanius, Cercopithecus nictitans , Cercopithecus neglectus, and Cercopithecus cephus), We observed a high de gree of genetic divergence among the species, The rate of accumulation of a mino acid mutations was, however, not higher in SIV carriers than in other nonhuman primates. No homozygous premature stop codons, deletions, or frame shift mutations were detected. Tn at least two animals, one infected AGM (C ercopithecus tantalus) and one noninfected monkey (Cercocebus aterrimus), t he CCR5 alleles identified encode functional proteins, as they were identic al in terms of amino acid sequence to that of functional CCR5 reported in t he literature. We found no other consistent differences in the genetic vari ability of CCR5-coding sequences between the nonhuman primates that are car riers of SIV and those that are not.