Concanavalin A crossed affinoimmunoelectrophoretic analysis of the major pig serum proteins during fetal development.

The interaction between concanavalin A (Con A) and alpha-fetoprotein (AFP), transferrin (TF), fetuin, alpha 1-antitrypsin (AT) and alpha 1-acid glycoprotein (AGP) has been analyzed by crossed affinoimmunoelectrophoresis (CAIE) in fetal extracts or sera, from 26-day-old porcine fetuses to birth, and in adult pigs. Most of the TF and AFP (100 and 85-90%, respectively) reacted with Con A during the entire developmental period. AGP showed both two reactive and one nonreactive Con A isoforms, whose proportions change greatly during development. In younger fetuses 100% of the protein was Con A-nonreactive. This variant represented 64% in 50-day-old fetuses, 80% in newborn pigs and 20% in adult sera. Fetuin and AT showed a maximum of three Con A-reactive microforms and one Con A-nonreactive microform, which was always a minor form. These microforms were detected mainly in young fetuses. Although the proportion of Con A-reactive variants of fetuin and AT changes during fetal development, the predominant microform was always that with intermediate affinity against Con A. The same microform was also predominant in adult AT, whereas the more reactive microform in respect to Con A predominates in adult fetuin.