IMMUNOLOGICAL INVESTIGATIONS ON EVOLUTION OF FIBRINOGEN AND PLASMINOGEN

The immunological cross-reactions of the plasmas from cattle, sheep, pig, guinea pig, rat and fowl with monospecific antisera against human fibrinogen and plasminogen were investigated in the Ouchterlony-test. Immunological relationship was found for both proteins with all mammalian plasmas investigated. Fowl plasma failed to react. The titres with the anti-plasminogenserum-with the exception of the guinea pig-were found to be higher than with the anti-fibrinogenserum. Cross-reactions with anti-fibrinogenserum were shown to be independent from the fibrinogen concentration as determined by the thrombin method. Relations between cross-reactions for fibrinogen and the differences in amino acid sequence of fibrinopeptides A and B, comprising about 10% of the amino acid residues of the whole molecule, could not be found. Titre differences however between two species were found to be the higher, the older the last common ancestor of these species is. © 1969 Springer-Verlag.