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

Area of Science:

• Immunogenetics
• Complement System Biology
• Mammalian Genetics

Background:

• The complement system is crucial for innate and adaptive immunity.
• Structural variations in complement proteins can impact immune responses.
• The major histocompatibility complex (MHC) plays a vital role in immune regulation.

Purpose of the Study:

• To investigate structural polymorphism of mouse complement C2.
• To identify genetic loci controlling complement C2 structure.
• To explore homology within the major histocompatibility complex.

Main Methods:

• Isolation of complement C2 from 17 mouse strains using immunoprecipitation.
• Analysis of structural polymorphism via sodium dodecyl sulfate-polyacrylamide gel electrophoresis and micro-peptide mapping.
• Tryptic digestion and peptide map comparison of complement C2.

Main Results:

• Two allotypic variations of mouse complement C2 were detected: C2.1 and C2.2.
• C2.1 was prevalent in common laboratory strains (B10 and 14 others).
• C2.2 was found in a wild mouse line (M.Mol-Ohm) and a congenic strain (B10.MOL.OHM), with codominant expression (C2.1.2) in F1 hybrids.

Conclusions:

• A codominant locus linked to the H-2 complex controls mouse complement C2 structure.
• This finding supports extensive homology of the major histocompatibility complex in vertebrates.
• Structural variations in complement C2 are genetically determined and linked to immune system loci.