CD4 cross-linking with gp160 and anti-gp160 in dominant negative ras mutant-transfected cells results in decreased TNF-α secretion. CD4⁺ Jurkat T cells were transiently transfected with the dominant negative ras mutant (rasN17) or control vector by electroporation as described in Materials and Methods. Concentration of plasmid DNA used for transfection (μg/mL) is indicated. CD4XL was performed with gp160 and anti-gp160 antibody. TNF-α in the culture supernatants was measured by ELISA. Mock-medium (▪), Mock-CD4XL (♦), RasN17-medium (•), RasN17-CD4XL (▴).