SUPPRESSIVE EFFECT OF SERUM FROM PIGS AND DOGS FED A DIET DEFICIENT IN VITAMIN-E AND SELENIUM ON LYMPHOCYTE-PROLIFERATION

The effect of sera collected from either pigs or dogs previously fed a vitamin E (vit E)- and selenium (Se)-deficient diet on in vitro lymph ocyte blastogenesis response to mitogens was studied. Porcine sera wer e obtained from pigs used in 2 different trials. In I trial, 4-wk-old pigs received either a basal diet deficient in vit E and Se or the bas al diet supplemented with Vit E, Se or Vit E and Se. Pigs were maintai ned on their respective diet for 25 d. Canine sera were collected from pups maintained on a deficient diet for 8 wk. Four dogs and 4 pigs ma intained on a commercial diet were used as donors of peripheral blood lymphocytes (PBL). The addition of sera from pigs or dogs maintained o n a vit E- and Se-deficient diet markedly suppressed both porcine and canine PBL response to mitogens. Porcine PBL blastogenesis was also su ppressed when porcine or canine sera were added 8, 24 or 48 h after th e beginning of the incubation period to culture containing 1% of fetal bovine serum (FBS). However, the suppressive effect caused by porcine sera was less severe than the one due to canine sera. Addition of 1% FBS in the cultures was sufficient to eliminate the suppression caused by the presence of sera from pigs fed a vit E- and Se-deficient diet Other attempts to restore the lymphocyte response to mitogens by the a ddition of indomethacin, diethylcarbamazine or eicosatetraynoic acid, inhibitors of prostaglandin and/or leukotriene synthesis, were not suc cessful. Because of the severe suppression caused by sera from animals maintained on a vit E- and Se-deficent diet on the in vitro response of lymphocytes to mitogenic stimulations, it is very important to take precautions to avoid such deficiency. In vivo suppression of immunoco mpetent cells to antigenic stimulations may impair the capacity of the host to control infections.