S100B and HIV-1 infection: The results from the evaluation of masCD3 downregulation align with what would be expected for a non-human primate model of HIV-1 infection, where CD3 downregulation is not observed in the presence of HIV-1 Nefs—like NL4.3 Nef—but does occur in the presence of other SIV Nefs such as SIVmac239 Nef (Fig. 2D).