H-2 antigens as genetic markers: a two-dimensional gel electrophoretic study.

Direct immunoprecipitation and two-dimensional (2D) gel electrophoresis have been used to identify and characterize genetic variation of the H-2K and H-2D regions. Using inbred strains of mice and alloantisera, haplotype-specific polypeptides were defined for five different H-2 haplotypes. Specific immunoprecipitates prepared from strains of different haplotypes were applied to 2D gels in pairwise combinations to determine whether peptides specific to one haplotype can be distinguished from peptides specific to another. Those haplotype-specific peptides that migrate to unique positions on 2D gels with respect to the positions occupied by haplotype-specific peptides of another haplotype are useful as biochemical genetic markers. Cross-reactivity among K- and D-region antigens of different haplotypes was identified on 2D gels and found to correlate well with existing data based on serological cross-reactivity. An anti-mouse beta 2-microglobulin serum was found to be a useful general reagent for immunoprecipitating haplotype-specific H-2 antigens to permit their visualization on 2D gels.