Long-term survivors with nonprogressive HIV-1 infection can carry crippled Nef (Deacon et al., 1995; Kirchhoff et al., 1995; Salvi et al., 1998), and destruction of the nef gene in SIV can preclude simian AIDS in macaque monkeys (Kestler et al., 1991). This evidence concerns the gene S100B and HIV-1 infection.