Application of immunoblotting to serum protein phenotyping with reference to alpha 2HS-glycoprotein (AHS) typing of bloodstains.

Sera and bloodstain extracts were subjected to isoelectric focusing in polyacrylamide gels. The focused proteins were transferred to nitrocellulose membranes by diffusion or electrophoretically, then allowed to react with specific antiserum and, after washing, with peroxidase-labeled anti-rabbit IgG. The immune complexes formed on the membranes were detected with 4-chloro-1-naphthol and hydrogen peroxide. Serum group-specific component, alpha 2HS-glycoprotein, the sixth and the seventh component of complement, factor 13B, and plasminogen could be phenotyped with high sensitivity. Bloodstains as old as 6 months could be correctly typed for alpha 2HS-glycoprotein by the blotting technique.