TgAb in relation to the MHC haplotype: H2 kk, kd, or kd (F2 progeny) and H2 kk or kd (N2 progeny). The haplotypes for NOD.H2h4 and BALB/c are kk and dd, respectively. In parentheses, the number of mice positive for TgAb vs the total number of mice. TgAb levels significantly higher for mice of kk than dd for F2: *analysis of variance, P < 0.05. The shaded area represents the mean ±2 standard deviations for values in BALB/c mice. OD, optical density.