ウシ血清α1-酸性糖蛋白の性状とその臨床測定意義

1. Bovine a1-acid glycoprotein (α1-AG) was purified from polled normal bovine sera by successive ammonium sulfate precipitation, ion-exchange chromatographies and gelfiltration. Bovine α1-AG had a molecular weight of 42, 000±2, 000 and sedimentation coefficient of 3.4s. It contained 26.6% carbohydrate. Gel isoelectric focusing revealed a microheterogeneity with 7 to 8 bands in a pI range of 3.2 to 3.7. It migrated to the α1-globulin region upon immunoelectrophoresis. Single radial immunodiffusion was developed for the quantitative measurement of bovine α1-AG in serum.<BR>2. Serum α1-AG levels increased during fetal development and neonatal stage. Mean ± SD serum α1-AG concentration reached a peak of 1, 368±207μg/ml immediately after birth, but thereafter gradually decreased, to 249±100, μg/ml, similar to the normal adult bovine range.<BR>3. By use of isoelectric focusing of thin-layer gels, detected 7 microheterogeneity bands ranging from pI 3.2 to 3.8 in adult bovine serum. Twelve bands ranging from pI 2.6 to 3.8 were found in the 9-month fetus and in neonates. The 5 most acidic bands, which are absent in adult serum, ranged between pI 2.6 and 3.1 and decreased with maturation as band patterns assumed adult characteristics. By crossed affinity electrophoresis, α1-AG of adult bovine serum was separated into 4 peaks according to its differential affinity to concanavalin A (Con A). Seventy-five percent of the α1-AG concentration was represented by peak 3 (P-3) and peak 4 (P-4), which had moderate or strong binding to Con A. In contrast, fetal sera contained only peak 1 (P-1) which did not have Con Abinding affinity. In neonatal sera, 4 peaks were recognized, of which P-1 comprised 70% of the total α1-AG present. Thereafter, with aging, percentage of P-3 and P-4 increased as band composition approached the normally expected adult pattern.<BR>4. Single radial immunodiffusion was developed to the guantitative measurement of bovine α1-AG in serum. The mean serum values of α1-AG in 152 healthy Holstein cattle (1-12 years old) was 283.2±82.3μg/ml. Elevated values (cut-off value=450, μg/ml) were observed in cattle with liver disorders (92%), pneumonia (92%), traumatic pericarditis (89%), peritonitis (100%), perinatal unability to stand (93%), fracture dislocation (100%), jones disease (100%), bovine viral diarrhea (100%), bovine leukemia (79%), and metabolic disorders (17%). Cattle with inflammatory diseases showed remarkably high α1-AG levels (1, 116.7±858.7μg/ml). In group I (recovered cases) showed almost the same level of serum α1 -AG abnormal cattle through the investigation period. The high levels returned to the normal levels according to the improvement of cilinical symptoms. In group II (unrecovered cases) maintained high levels of about over 1, 000μg/ml during the observation period. These animals were slaughtered or autopsied within a short period after initial examination.<BR>5. In the cases with laparotomy, the levels of almost recoverered cattle reached a maximum 3-7 days after operation, and thereafter recovered to the preoperative or normal level 15-40 days after operation. In the case with postoperative peritonitis, the high serum α1-AG level was maintained high until autopsy. On the day before autopsy, the level was further increased. Those results suggest that serum α1-AG level in recovered cases was not incresed, while it was high in unrecovered cases. As an indicators for the diagnosis of inflammatory disease, the assay of serum α1-AG seemed to be very useful for evaluation of an appropriate treatment and of condition of postoperative course in cattle.