RESPONSE OF PERIPHERAL-BLOOD LEUKOCYTES TO MITOGENIC FACTOR(S) IN PORCINE SEMINAL PLASMA

Porcine seminal plasma (PSP) contains a potent mitogenic substance cap able of causing proliferation and extensive agglutination in cultured porcine peripheral blood leucocytes (PBL). In order to determine the s pecific leucocyte cell population affected by this mitogen, lymphocyte , monocyte and polymorphonuclear (PMN)-enriched cell fractions were se parated from PBL and treated with increasing concentrations of PSP (1- 8%, v/v). For monocyte cell populations enriched through elutriation a nd adherence to plastic, cell proliferation in response to PSP treatme nt was consistently higher than PSP-treated unfractionated PBL. Monocy te-depleted PBL and lymphocyte populations enriched through elutriatio n demonstrated a decrease in proliferation compared to PSP-treated unf ractionated PBL. PMN populations separated from PBL by discontinuous P ercoll gradient centrifugation were unresponsive to PSP. Agglutination was observed for the unfractionated PBL and each enriched cell popula tion. These results demonstrate that PSP contains a potent mitogen whi ch induces proliferation in monocyte-enriched cell populations and may reflect the potential of PSP to act as an immune regulator in the ute rine environment during early embryo development and implantation.