In vivo administration of mγ3-anti CD3ɛ and mitogenic anti-CD3ɛ administration. (A) BALB/c mice were treated on day 0 with control antibody, mγ3-anti-CD3ɛ, or anti-CD3ɛ (30 μg IV) and analyzed on day 1 for CD3ɛ expression. Pooled spleen cells from 3 individuals in each group were analyzed by immunofluorescence after staining with FITC-labeled anti-CD3ɛ. (B) BALB/c mice (5 per group) were treated with control antibody, mγ3-anti CD3ɛ, or anti-CD3ɛ. Mice were bled 2 hours later and the serum IL-2 activity was tested by ELISA. Results are expressed as the mean absorbance (492 nm) ± SD of individual determinations.