Immunological properties of canine prothrombin, its activation products, plasma and serum

Abstract

Immunological properties of canine prothrombin(PO), prethrombin 1 (P1), fragment 1(F1), fragment 2(F2), thrombin(T1), plasma and serum were studied by the use of immunoelectrophoresis(IEP), crossed immunoelectrophoresis (CIEP) and Ouchterlony analysis. Antibodies against P0 and T1 were used. The results showed that P0, P1, F1, F2 and T1 all had a variable affinity with anti-PO antibody but that only P0, P1 and T1 had a demonstrable affinity with anti-T1 antibody. F1 and F2 did not show any detectable affinity. Quantitative affinity study by the use of I-125-labeled proteins gave the following average values for % bound I-125-proteins in 3 hr incubation with the antibody against P0 or T1: with anti-P0 antibody, 81 ± 2 (SD) % for I-125-P0, 79.1 ± 2(SD) % for I-125-P1, 23.5 ± 3(SD) % for I-125-F1, 25.5 ± 2(SD) % for I-125-F2 and 25.2 ± 3(SD) % for I-125-T1, and with anti-T1 antibody, 28 ± 2(SD) % for I-125-P0, 80.5 ± 2(SD) % for I-125-P1, 1.0 ± 0.03(SD) % for I-125-F1, 1.3 ± 0.03(SD) % for I-125-F2, and 81 ± 3(SD) % for I-125-T1. With the use of CIEP and anti-P0 antibody, serum was found to contain F1, F2 and a trace amount of P1, and plasma contained only P0, but upon activation with tissue thromboplastin, plasma was found to generate P1, F1, F2 and T1 with time. These results indicate that a simple, specific and quantitative immunoassay of T1 by the use of anti-T1 antibody or anti-P0 antibody may not be possible at least in dogs, but that CIEP by the use of anti-P0 antibody might be used as a diagnostic means of in vivo P0 activation.