CD8B and infection: In addition to anti-FIV neutralizing antibodies and cytotoxic and noncytotoxic CD8+ T cells, the primary (acute) stage of infection is known to be characterized by the appearance and expansion of a CD8+ T-cell subpopulation with an activated phenotype showing reduced expression of the CD8β chain and the complete disappearance of the L-selectin CD62L surface molecule [8].