Evidence for maternal effect in the regulation of basal levels of immunoglobulin A in mice

A congenic pair of mice, C57BL/10 and C57BL/10.F, have been shown to have different basal serum levels of IgA. The serum IgA level of B10 is 254 +- 33 mg/d1 and B10.F is 67 +- 8 mg/d1. Unexpectedly, reciprocal F/sub 1/ hybrids between these strains also have different basal serum levels. The (B10 x B10.F)F/sub 1/ has a basal serum IgA level of 353 +- 33 mg/d1 and (B10.F x B10)F/sub 1/ has a basal serum level of 92 +- 10 mg/d1. Thus, the F/sub 1/ hybrids of the high maternal parent have high circulating levels of IgA and the F/sub 1/ hybrids of the low maternal parent have low circulating levels. The low phenotype segregates in F/sub 2/ and backcross populations. Since these mice are congenic at the major histocompatibility complex, H-2, the progeny were also tested for their H-2 haplotype. The segregation ratios suggest that at least 2 genes control the immunoglobin levels. One of the genes is linked to H-2. The maternal parent of the F/sub 1/ hybrid influences the expression of the serum IgA levels among the backcross and F/sub 2/ progeny, but the data show that the maternal effect is not due to a sex-linkedmore » recessive gene. The basis of the maternal effect is under investigation.« less