Transfection of E1B-containing cDNA into Jurkat cells reduces their membrane expression of the CD5 protein. (A) The The pLP env vector, with or without E1B-containing cDNA, was introduced into Jurkat cells. The CD5^lo cells were sorted and cultured and their membrane density of CD5 determined using PE-conjugated UCHT2 anti-CD5 antibody. (B) Quantitative RT-PCR demonstrates that the diminished expression of CD5 did not result from a reduction in the amount of E1A-containing transcripts. Data represents mean and SD of 3 experiments. (C) The E1A-related variant of CD5 was detected by blotting total cell extracts with the E1A-related variant-specific Leu-1 anti-CD5 antibody.