ADMINISTRATION OF 13-CIS-RETINOIC ACID TO DAIRY-CATTLE .2. PHENOTYPE OF BLOOD LEUKOCYTES AND PRODUCTION OF IMMUNOGLOBULIN

Eight Holstein dairy cattle were assigned randomly to treatments in three replicate experiments evaluating the effects of 13-cis-retinoic acid on mononuclear leukocyte function. Treatments were i.m. injections of 0 (vehicle only), 100, 200, or 400 mg/d of 13-cis-retinoic acid in dimethylsulfoxide for 7 consecutive d. Peripheral blood was collected before treatment and periodically for 18 d after initiation of treatments. Parameters measured were IgM production in vitro by blood lymphocytes, serum Ig concentrations, and the phenotype of peripheral blood mononuclear leukocytes. Administration of 13-cis-retinoic acid had no effect on in vitro Ig production induced by poke-weed mitogen; however, supplementation of the same cultures with 13-cis-retinoic acid enhanced production of polyclonal IgM. Serum Ig concentrations and total numbers of peripheral blood leukocytes and numbers within mononuclear leukocyte subsets were unaffected by treatment with 13-cis-retinoic acid. Experimentally induced elevations in the concentrations of serum and intracellular retinoic acids did not affect mononuclear leukocyte function in vivo.