S100B and lentivirus infection: Significant levels of protection have been achieved against primate lentivirus infection with live-attenuated SIV [2,3,40,41], although translation of such strategy to humans is unacceptable due to the residual pathogenic potential of standard nef-deleted vaccine viruses, including nef-deleted HIV-1 [21,22], and recombination between vaccine and challenge viruses [10].