Increased IL-12 p40 expression in tc-ptp^-/- mice. The mRNA levels for IL-12 p40 subunit in (A) spleen, thymus, and liver at 3 days and (B) spleen, liver, and salivary gland at 2 weeks after birth. Bars represent the mean values ± SE from 4 mice, with tc-ptp^-/- values (▪) shown as fold increase from those of age-matched tc-ptp^+/+ mice (□). Statistical significance was determined by a 2-tailed unpaired Student t test. ^*P < .05 tc-ptp^-/- compared with tc-ptp^+/+.