IL-6 secretion induced by mCD40-hP227A versus mCD40-hCD40 in the human B-cell line, T5-1. T5-1.mCD40-hCD40 (MH40WT-n24.7, MHWT-n24.12) and T5-1.mCD40-hP227A (MHP227A-n22.7, MHP227A-n22.12) were stimulated with Hi5-mCD154 plus R848 for 48 hours and supernatants analyzed by ELISA for human IL-6. Data are presented as means plus or minus SD of background-corrected IL-6 in replicate cultures from 3 separate experiments. Asterisk denotes statistically significant difference (*P < .05) between MH40WT and MHP227A by 2-tailed Student t test.