To characterize the effects of HIV-1 on host gene expression, Jurkat T cells (CD4+ T lymphoblastoma cell line, clone E6.1) were exposed or not to HIV-1 (NL4-3 strain) at a multiplicity of infection (m.o.i.)of 0.6, thus achieving after 48 hr maximal infection efficiency (∼70%), as determined by measuring the percentage of cells expressing the p24 Gag capsid antigen ([5] and data not shown), with a ∼85% cell viability as evaluated by trypan blue exclusion. This evidence concerns the gene CD4 and infection.