Structural polymorphism of mouse complement C2 detected by microscale peptide mapping: linkage to H-2.

Complement C2 was isolated from 17 mouse strains by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and examined for structural polymorphism by using micro-peptide mapping. By comparing the peptide maps of tryptic digest of C2 from various strains, two allotypic variations were detected. B10 and 14 other mouse strains demonstrated C2.1 type, while a wild mouse line (M.Mol-Ohm) and one B10 congenic strain, B10.MOL.OHM, which carries the H-2 derived from M.Mol-Ohm, demonstrated C2.2 type. (B10 X B10.MOL.OHM)F1 demonstrated codominantly expressed C2 type (C2.1.2). Desialation of mouse C2 did not abolish the observed variation of mouse C2. It is concluded that an H-2-linked codominant locus controls the structure of mouse complement C2, further confirming the extensive homology of the major histocompatibility complex among higher vertebrate species.