Suppression of interleukin-2 mediated T-lymphocyte blastogenesis by bovine uterine secretions

Uterine luminal protein (ULP) secretions collected on day 17 of bovine pregnancy contain high (greater than or equal to 248 kDa)- and low (7, 21.0, and greater than or equal to 72 kDa)-molecular weight (Mr) components that suppressed incorporation of thymidine into both phytohemagglutinin (PHA)-stimulated and interleukin-2 (IL-2)-stimulated bovine lymphocytes. The pattern of suppressor activity for ULP was similar for both PHA and IL-2 cultures. For IL-2-treated lymphocytes (2 X 10(4)/culture well), mean percentage of control (no test protein) values for 8 and 32 micrograms/ml of high Mr ULP were 94.6% and 4.5%, respectively; whereas, mean values for 8 and 64 micrograms/ml of combined low Mr ULP components were 51.2% and 5.5%, respectively. The data indicate that specific bovine ULP components may locally affect T-lymphocyte function by altering some facet of the IL-2 activation system.