Glucocorticoid effects on peripheral blood lymphocytes in cows infected
with bovine leukemia virus
JC Bloom, SJ Kenyon and TG Gabuzda
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.
Volume 53,
Issue 5,
pp. 899-912,
05/01/1979
Copyright © 1979 by The American Society of Hematology
