Dynamics of T-suppressor and T-helper lymphocytes and haemolytic plaque-forming cells during normal pregnancy in the sow.

T gamma and T mu lymphocytes and haemolytic plaque-forming cells (PFC) were quantitatively determined in peripheral blood and uterine draining lymph nodes ( DLN ) from 36 nonpregnant and 45 pregnant sows. A considerable increase in the number of T gamma cells occurred both in the blood and the DLN during pregnancy (P less than 0.001). This increase was higher at the beginning of pregnancy (20th-40th day) and lower at the end (80th- 110th day). No significant quantitative changes were found in T mu cells. During pregnancy there was a marked drop in the number of cells in the peripheral blood manifesting direct erythrocytolytic activity (DECA), as well as of haemolysin-producing cells.