IN-VITRO AND IN-VIVO INTERFERON-PRODUCTION BY BOVINE COLOSTRAL LEUKOCYTES

Sixteen healthy pregnant cows were divided into two groups. Group I (8 cows) received immediately after calving two injections of Vaccina L containing the LaSota strain of Newcastle Disease Virus (total dose 10 (9) TCID50/cow) into udder lymph nodes. The second group of 8 cows ser ved as control. Newborn calves of both groups of cows were allowed to suckle the colostrum. Interferon activity was detected 24 h after inje ction in whey obtained from colostrum of Vaccina L - treated dams and in supernatants of cultures of colostral leukocytes. Interferon was al so present in sera of Vaccina L treated dams 48 h after injection. No IFN activity was detected in sera of calves. Cultures of leukocytes ob tained from colostrum of dams 48 h after Vaccina L-treatment exhibited hyporeactivity to the second induction in vitro and produced low IFN levels in response to NDV. In contrast to hyporeactivity observed in c olostral leukocytes, peripheral blood leukocytes (PBL) of calves suckl ing colostrum from dams treated with Vaccina L produced higher IFN lev els after induction in vitro with NDV than leukocytes of control calve s.