Effects of anti–vIL-6 antibody on B9 cell proliferation induced by viral and human IL-6. Exponentially growing B9 cells (2 × 10³ cells/microwell) were cultured in medium alone or medium supplemented with vIL-6 (MBP-vIL-6; 1 to 100 ng/mL) or human IL-6 (1 to 100 pg/mL), with (□) or without (▪) anti–vIL-6 antibody (10 μg/mL). ³H thymidine was added during the final 6 hours of culture. The results represent the mean radioactivity of triplicate cultures; SDs were within 5% of the mean.