Genetic regulation of antibody response to sheep red blood cells: isoelectric focusing analysis of sera of well responding strain A/J and poorly responding strain B10 mice.

Isoelectric focusing (IEF) on a thin layer of polyacrylamide gel revealed that strain A/J produces antibodies with pI values distributed over the whole assayed pH range (pH 5.05-7.75), while strain B10 produces antibodies of a limited heterogeneity with pI values distributed between pH 6.3 and 7.5. The analysis of sera of congenic resistant (CR) and recombinant strains showed that haplotype H-2a is associated with wide-heterogeneity antibodies, while the presence of haplotype H-2b is associated with the occurrence of limited-heterogeneity antibodies. Thus a gene located within the I region of the major histocompatibility complex (MHC) may affect the degree of heterogeneity of the anti-sheep red blood cell (SRBC) response. The gene is transmitted to the F1 generation as a dominant trait. After administration of endotoxin (LPS LT2, 10 microgram/mouse) to the B10 mice, antibodies with pI values below pH 6.3 and above 7.5 appear in the serum; the heterogeneity of these antibodies resembles that of the A/J strain spectrotype.