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 pokeweed 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.