(n = 8 independent donors) The result for each vpr-null or vpr-nef-null mutant was normalized to the vpr- and nef-competent virus encoding the same env. (I) Western blot analysis of MDM infected as in G. The lysates from the vpr-competent and nef-competent infections were diluted to facilitate comparisons to vpr- and nef-null mutants. This evidence concerns the gene S100B and infection.