RESUMO
PROBLEM: To determine whether prostatein, the major protein produced and secreted into the seminal fluid by the rat ventral prostate has any effect on the phagocytic cell functions in vitro. METHOD OF STUDY: Analysis was done by determining if purified prostatein added to cells obtained from the peritoneal cavity has any effect on their phagocytic and intracellular killing capacity. Also, we analyzed the effect of prostatein on the production of oxygen and nitrogen intermediates, measuring these metabolites by Nitroblue tetrazolium assay and by the Griess reaction respectively. RESULTS: Prostatein possess the ability to inhibit in vitro the phagocytic and killing properties of peritoneal rat leukocytes in a dose-dependent manner. The addition of a polyclonal antiserum against prostatein specifically blocks this inhibitory effect. Moreover, prostatein inhibits the production of oxygen and nitrogen intermediates by these cells. CONCLUSION: Regulation of the production of reactive oxygen species in the reproductive tract is extremely necessary to avoid their deleterious effects on the sperm motility and the fertilization process. We propose that prostatein, a protein supplied by an accessory gland like prostate, can inhibit the macrophage function, showing an important antioxidant effect.
Assuntos
Proteína de Ligação a Androgênios/farmacologia , Fagócitos/imunologia , Proteína de Ligação a Androgênios/fisiologia , Proteína de Ligação a Androgênios/toxicidade , Animais , Líquido Ascítico/citologia , Líquido Ascítico/metabolismo , Relação Dose-Resposta a Droga , Feminino , Leucócitos/química , Masculino , Fagócitos/citologia , Fagócitos/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Próstata/química , Prostateína , Ratos , Ratos Wistar , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Secretoglobinas , Sêmen/química , UteroglobinaRESUMO
Prostatic steroid binding protein (PSBP) is the major protein produced ( approximately 20% of the total cytosolic protein) and secreted into the seminal fluid by the rat ventral prostate but its physiological function has not been elucidated yet. Since PSBP is secreted into the seminal fluid (which is itself a potent immunosuppressor) and has strong homology with uteroglobin (which possess an important anti-inflammatory function) our aim was to determine what effect, if any, PSBP would have on the immune system. With that purpose in mind we performed mononuclear cell cultures in the presence or absence of purified PSBP and analysed the effect of this protein on different functional parameters. PSBP inhibits the mitogen-induced proliferation of normal rat spleen mononuclear cells (MNC) specifically and in a dose-dependent manner. It reduces the production of IL-2 and the expression of its receptor (analysed by flow cytometry) which are important events for lymphocyte proliferation. Also, PSBP was able to inhibit OVA-specific proliferation of lymph node cells from previously primed animals. The immunosuppressive effect of PSBP is not due to an inherent toxic effect to the cells, since the cell viability was kept intact at the different times of culture studied. We also analysed the effect of rat PSBP on mitogen-induced proliferation of mouse spleen and human blood MNC. The proliferation was strongly abolished in a dose-dependent and non-species specific fashion. Moreover, PSBP strongly inhibits the human mixed lymphocyte reaction. Taken together, the present data support evidence for a new type of function for PSBP. We report that PSBP is a potent immunosuppressor factor and we describe its effect on the immune function in vitro. Here, we discuss the possible implications of these findings in the protection of sperm from immunologic damage in the feminine reproductive tract.