Mitogenic effect of prolactin on chicken lymphocytes in vitro

Lymphocytes obtained from thymus and spleens of 1-6 week old White Leghorn cockerels, untreated or immunized twice with sheep red blood cells (SRBC), were cultured with common T-cell mitogens in serial dilutions and/or different concentrations of bovine prolactin (PRL). [3H]Thymidine incorporation in newly synthesized DNA was used as a measure of lymphocyte mitogenic stimulation. Lymphocytes were stimulated by mitogens, as well as by PRL alone, in a dose-dependent way. Cell cultures prepared from immunized and non-immunized donors differed in their response to mitogens or PRL. The present results demonstrate direct PRL action on avian lymphoid cells and resemble those found in the mammalian immune system.