While ∼50% of the helped cells were CD62LhiCD44hi Tcm, most helper-deficient T cells were CD62LlowCD44hi effector (Teff) or effector memory (Tem) cells, consistent with the phenotype of CD8+ T cells observed in the memory phase after infection of Cd4−/− mice with lymphocytic choriomeningitis virus28. This evidence concerns the gene CD4 and infection.