Abstract
An antiserum against the extract of equine allantoamniotic membrane was absorbed with the colt liver extract. This antiserum gave four precipitations in immunoelectrophoresis with extract of allantoamnion as the antigen. The four precipitates exhibited electrophoretic mobility of prealbumin area and were termed antigens A, B, C and D. The antiserum also reacted with amniotic fluid, whereas no precipitin band was visible when pregnant mare serum (days120-270) was tested against absorbed antiserum. The equine allantoamniotic antigens were purified from the extract of allantoamnion by gel filtration, anion exchange chromatography, isoelectric focusing and affinity chromatography. Antigen A had a molecular weight of about 50, 000 and an isoelectric point of 3.8-4.0. Antigen B and C had a molecular weight of about 21, 500. The isoelectric point of antigen B was 3.7-4, 0 and that of antigen C was 3.4-3.6.
