title: Glucocorticoid effects on peripheral blood lymphocytes in cows infected with bovine leukemia virus.
abstract: We examined the effects of glucocorticoids on peripheral blood lymphocytes (PBL) in lymphoproliferative conditions associated with bovine leukemia virus (BLV): persistent lymphocytosis (PL) and lymphosarcoma cell leukemia (BLSL). The effects of hydrocortisone 21-sodium succinate (HSS) on spontaneous incorporation (SI) and mitogen-stimulated incorporation of radiolabeled-thymidine and the effects of intramuscular administration of prednisolone acetate were studied. An expanded population of B lymphocytes in cows with PL was remarkable sensitive to glucocorticoids in vitro and in vivo. SI was markedly inhibited by concentrations of HSS as low as 10(-7) M. These results correlated well with in vivo observations, where an 80%-90% decrease in PBL occurred during the course of glucocorticoid administration. The decrease in total lymphocytes was accounted for almost entirely by a decrease in the expanded B lymphocyte population. Steroid-sensitive lymphocytes together with steroid-resistant cells were observed in cows with BLSL. The reduction in the steroid-sensitive lymphocytes was associated with rapid disease progression in cows with lymphosarcoma. Steroid-sensitive lymphocyte populations in cows with BLSL may include the same reactive B-cell population found in cows with PL. Glucocorticoids may prove to be a useful tool for study of the immune response to the oncogenic virus and lymphoma in BLV-infected cattle.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D002417:Cattle; D002499:Centrifugation, Density Gradient; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use*; D007938:Leukemia / Q000150:complications / Q000276:immunology*; D001909:Leukemia Virus, Bovine / Q000276:immunology; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000187:drug effects*; D008218:Lymphocytosis / Q000150:complications; D011239:Prednisolone / Q000627:therapeutic use
chemical_list: D005938:Glucocorticoids; D011239:Prednisolone