Purified porcine seminal plasma protein enhances in vitro immune activities of porcine peripheral lymphocytes

• Published in: Biology of reproduction Vol. 59; no. 1; pp. 202 - 207
• Main Authors: Yang, W.C. (Food and Drug Administration, Rockville, MD.), Kwok, S.C.M, Leshin, S, Bollo, E, Li, W.I
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01-07-1998
• Subjects: ANIMAL PROTEINS; Animals; BINDING SITES; Biological and medical sciences; Biotinylation; CELL MEDIATED IMMUNITY; Cells, Cultured; CERDO; Concanavalin A - pharmacology; DNA - biosynthesis; DOSAGE; DOSIFICACION; EXPERIMENTACION IN VITRO; EXPERIMENTATION IN VITRO; Female; Fundamental and applied biological sciences. Psychology; IMMUNE RESPONSE; IMMUNITE CELLULAIRE; IN VITRO EXPERIMENTATION; INMUNIDAD CELULAR; LINFOCITOS; LOCALIZATION; LYMPHOCYTE; Lymphocyte Activation - drug effects; LYMPHOCYTE TRANSFORMATION; LYMPHOCYTES; Lymphocytes - drug effects; Lymphocytes - immunology; Male; Mammalian male genital system; MITOGENE; MITOGENOS; MITOGENS; Mitosis; MIXED LYMPHOCYTE REACTION; Morphology. Physiology; Phytohemagglutinins - pharmacology; Pokeweed Mitogens - pharmacology; PORCIN; Prostatic Secretory Proteins; PROTEINAS; PROTEINE; PROTEINS; Proteins - isolation & purification; Proteins - pharmacology; REPONSE IMMUNITAIRE; RESPUESTA INMUNOLOGICA; SEMEN; Seminal Plasma Proteins; SPERME; SWINE; Vertebrates: reproduction; Vertebrata; Mammalia; Semen; Cellular immunity; Binding site; Artiodactyla; Seminal plasma; Localization; Lymphocyte; Ungulata; Protein; Pig
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod59.1.202

The porcine seminal plasma protein (PSP) accounts for much more than 50% of the total proteins in seminal plasma. PSP has
been previously purified and its biochemical properties characterized. However, the biological functions of PSP remain to
be elucidated. We hypothesize that PSP is involved in the regulation of uterine immune activity. In the current study, effects
of PSP on in vitro lymphocyte activities and the presence of PSP binding sites on lymphocytes were examined. In mitogen-induced
proliferation assay, lymphocytes from peripheral blood of gilts were cultured with pokeweed mitogen (PWM), phytohemagglutinin
(PHA), or concanavalin A (Con A) in the presence or absence of PSP. PSP at 50, 125, and 250 ng/well augmented PWM-induced
[ 3 H]thymidine uptake in a dose-responsive manner by 152.8 ± 8.1%, 225.9 ± 35.2%, and 274.8 ± 53.6%, respectively, compared with
that of control. PSP did not alter lymphocyte proliferation in the absence of PWM. Similarly, PSP had little or no effect
on PHA- or Con A-induced lymphocyte proliferation. In one-way mixed lymphocyte reactions, PSP at 50, 125, and 250 ng/well
enhanced [ 3 H]thymidine uptake in a dose-responsive manner by 181.5 ± 16.5%, 339.9 ± 48.2%, and 600.1 ± 84.8% of control, respectively.
Using biotinylated PSP-I, PSP binding sites were localized on approximately 3–5% of the lymphocyte population. In summary,
we have demonstrated that PSP itself is not a mitogen/antigen to porcine lymphocytes but that it has a stimulatory effect
on lymphocyte activities initiated by PWM or surface antigens of lymphocytes. PSP may exert its functions by interacting with
PSP binding sites on a subpopulation of porcine lymphocytes. The high potency of PSP on lymphocyte activities and the abundance
of PSP in seminal plasma have suggested that PSP may play an important role in regulating immune responses in the porcine
uterine environment.