Immunohistochemical localization of α1-acid glycoprotein in liver tissues of bovine fetuses, newborn calves, and sick or healthy adult cattle

Abstract

Objective - To detect localization of α1-acid glycoprotein (α1-AG) antigens in the liver tissue of cattle by use of immunoperoxidase technique. Sample Population - Liver specimens from 6 bovine fetuses, 2 healthy bovine neonates, 2 healthy adult cattle, 3 cattle with experimentally induced hepatic abscesses, and 2 cattle with enzootic bovine leukosis (EBL). Procedure - 3 cattle (with hepatic abscesses) were inoculated with a suspension of Fusobacterium necrophorum in the ruminal vein. Serum α1-AG concentration was determined by use of the single radial immunodiffusion method. Livers from fetuses, newborn calves, and adult or sick cattle were fixed in buffered 10% formalin, dehydrated in alcohol, embedded in paraffin, sectioned, and stained by use of the avidin-biotin complex/immunoperoxidase technique. Results - Sites of localization of the α1-AG antigen positive reaction (AGPR) in the liver obtained from bovine fetuses, neonates, or sick cattle were different. In fetal and newborn calves, the AGPR was detected in the cytoplasm of hepatocytes. Intensity of the reaction varied in direct proportion to α1-AG serum concentration. In adult cattle, the AGPR was particularly intense in hepatocytes adjacent to abscesses or EBL-induced tumors. Conclusions - The pattern of distribution of cells with AGPR in the liver varied, depending on severity of inflammation. In the cattle with EBL, whether the AGPR was attributable to inflammation could not be clarified, although suppression of immunologic response to tumors may have been a cause of the observed reaction. This association that the glycoprotein may be synthesized, mainly in hepatocytes.