The immunosuppressive contribution of prostaglandin components of human semen and their ability to elevate cyclic adenosine monophosphate levels in peripheral blood mononuclear cells

The Female Response to Seminal Fluid

Seminal fluid is often assumed to have just one function in mammalian reproduction, delivering sperm to fertilize oocytes. But seminal fluid also transmits signaling agents that interact with female reproductive tissues to facilitate conception and .pregnancy. Upon seminal fluid contact, female tissues initiate a controlled inflammatory response that affects several aspects of reproductive function to ultimately maximize the chances of a male producing healthy offspring. This effect is best characterized in mice, where the female response involves several steps. Initially, seminal fluid factors cause leukocytes to infiltrate the female reproductive tract, and to selectively target and eliminate excess sperm. Other signals stimulate ovulation, induce an altered transcriptional program in female tract tissues that modulates embryo developmental programming, and initiate immune adaptations to promote receptivity to implantation and placental development. A key result is expansion of the pool of regulatory T cells that assist implantation by suppressing inflammation, mediating tolerance to male transplantation antigens, and promoting uterine vascular adaptation and placental development. Principal signaling agents in seminal fluid include prostaglandins and transforming growth factor-β. The balance of male signals affects the nature of the female response, providing a mechanism of ‟cryptic female choiceˮ that influences female reproductive investment. Male-female seminal fluid signaling is evident in all mammalian species investigated including human, and effects of seminal fluid in invertebrates indicate evolutionarily conserved mechanisms. Understanding the female response to seminal fluid will shed new light on infertility and pregnancy disorders and is critical to defining how events at conception influence offspring health.

Tissue-specific HIV-1 infection: why it matters

The human immunodeficiency virus displays a narrow tropism for CD4⁺ mononuclear cells, and activated CD4⁺ T lymphocytes are the main target. When these cells are depleted by viral replication, bystander apoptosis and increased cell turnover mediated by immune activation, there is a progressive immunodeficiency (i.e., AIDS). Despite this specific cell tropism, HIV-infected persons demonstrate pathology in nearly every organ system. This article reviews current understanding of tissue-specific HIV-1 infection in the CNS, the genital tract, and gastrointestinal-associated lymphoid tissue.

Effects of boar seminal immunosuppressive fraction on production of cytokines by Concanavalin A-stimulated spleen cells and on proliferation of B lymphoma cell lines

PROBLEM

The immunosuppressive fraction (ISF) of boar seminal vesicle fluid has recently been demonstrated to inhibit mitogen-stimulated proliferation of lymphocytes and antibody response to corpuscular and soluble antigens. The effects of ISF on in vitro and in vivo production of cytokines as well as its possible inhibitory effect on proliferation of B lymphoma cells remain to be elucidated.

METHODS

The effect of ISF on proliferation of normal mouse spleen cells stimulated by Concanavalin A (Con A) and on mouse B lymphoma cells was measured by 3H-thymidine incorporation. Cytokines were determined in the supernatants of mouse spleen cells stimulated with Con A in the presence or absence of ISF by enzyme-linked immunosorbent assay (ELISA). In vivo cytokine production in the sera samples of mice treated with ISF and immunized with keyhole limpet hemocyanin (KLH) was followed by ELISA, too.

RESULTS

We confirmed the inhibitory effect of ISF on Con A-stimulated lymphocyte proliferation. ISF affected cytokine production in the Con A-stimulated spleen cells: production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) was lowered, but production of IL-4, IL-6, and IL-10 was enhanced. Similarly, in the sera samples of mice immunized with keyhole limpet hemocyanin (KLH), IL-2 and IFN-gamma levels were decreased by ISF. ISF inhibited proliferation of Ag 8 and X 63-IL-2 B lymphoma cells as well.

CONCLUSIONS

ISF inhibited production of T helper1 (Th1) cytokines (IL-2 and IFN-gamma) and enhanced production of Th2 cytokines (IL-4, IL-6, and IL-10). ISF seems to shift the Th1/Th2 pattern in favor of Th2. ISF exhibited an antiproliferative activity on mouse B lymphoma cells.

Reverse effect of indomethacin on the immunosuppressive activity of boar seminal immunosuppressive fraction

The inhibitory activity of seminal immunosuppressive fraction (ISF) on mitogen-stimulated lymphocyte proliferation and on production of antibody to a soluble antigen was modified by indomethacin or monoclonal antibody to ISF. The ability of indomethacin or monoclonal antibody to ISF to reverse the ISF-induced inhibition of mitogen-stimulated lymphocyte proliferation was estimated by measuring bromodeoxyuridine incorporation into replicated DNA. Splenocytes from mice treated with indomethacin or monoclonal antibody to ISF prior to the application of ISF were tested. The ability of indomethacin or monoclonal antibody to ISF to reverse ISF-induced suppression of antibody production was estimated by measuring antibody titers by ELISA in the blood sera from mice immunized with keyhole limpet hemocyanin (KLH). These animals were treated with indomethacin or monoclonal antibody to ISF prior to the application of ISF. The results showed that both indomethacin and monoclonal antibody to ISF reversed the inhibitory effect of ISF on mitogen-stimulated lymphocyte proliferation as well as on antibody production.Recently, we have identified ISF as a complex of the major seminal glycoproteins PSP I and PSP II. PSP II is the part that is responsible for immunosuppressive properties of the complex. To learn whether the ISF immunosuppressive effect is associated with its protein or saccharide part, we examined the deglycosylated PSP II for its antiproliferative effect on mitogen-stimulated mouse lymphocytes. The results suggest that deglycosylation of PSP II did not affect its antiproliferative activity. This suggest that PSP II immunosuppressive properties are associated with the protein and not the saccharide part of the molecule.

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

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 [3H]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 [3H]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.