Fig 4.

Comparison of Nef-mediated receptor modulation by human and nonhuman primate lentiviruses. Quantitative assessment was performed to measure down-modulation of the A2-CD8β fusion (A), MHC-I (B), CD4 (C), and CD28 (D) by nef alleles, based on the species of origin (humans versus nonhuman primates) and biological properties (unable or able to down-modulate TCR-CD3) of the nef alleles examined. A2-CD8β fusion modulation was measured in CEM cells, and down-modulation of the remaining receptors was measured in primary CD4⁺ T cells. Abbreviations: Pr, precursor; Hu, human; NHP, nonhuman primate.