S100B and AIDS: These observations were confirmed by experimental evidence from studies employing the SIV-rhesus model, notably by the Desrosier's group (Kestier et al., 1991) who showed that SIV variants with nef gene deletions, but not wild type SIV, failed to maintain high viral loads necessary to cause AIDS in infected adult rhesus monkeys (Kestier et al., 1991).