Germ cell-induced immune suppression in mice. Effect of inoculation of syngeneic spermatozoa on cell-mediated immune responses

Sertoli Cell Immune Regulation: A Double-Edged Sword

The testis must create and maintain an immune privileged environment to protect maturing germ cells from autoimmune destruction. The establishment of this protective environment is due, at least in part, to Sertoli cells. Sertoli cells line the seminiferous tubules and form the blood-testis barrier (BTB), a barrier between advanced germ cells and the immune system. The BTB compartmentalizes the germ cells and facilitates the appropriate microenvironment necessary for spermatogenesis. Further, Sertoli cells modulate innate and adaptive immune processes through production of immunoregulatory compounds. Sertoli cells, when transplanted ectopically (outside the testis), can also protect transplanted tissue from the recipient’s immune system and reduce immune complications in autoimmune diseases primarily by immune regulation. These properties make Sertoli cells an attractive candidate for inflammatory disease treatments and cell-based therapies. Conversely, the same properties that protect the germ cells also allow the testis to act as a reservoir site for infections. Interestingly, Sertoli cells also have the ability to mount an antimicrobial response, if necessary, as in the case of infections. This review aims to explore how Sertoli cells act as a double-edged sword to both protect germ cells from an autoimmune response and activate innate and adaptive immune responses to fight off infections.

Testisimmune privilege - Assumptions versus facts

The testis has long enjoyed a reputation as an immunologically privileged site based on its ability to protect auto-antigenic germ cells and provide an optimal environment for the extended survival of transplanted allo- or xeno-grafts. Exploration of the role of anatomical, physiological, immunological and cellular components in testis immune privilege revealed that the tolerogenic environment of the testis is a result of the immunomodulatory factors expressed or secreted by testicular cells (mainly Sertoli cells, peritubular myoid cells, Leydig cells, and resident macrophages). The blood-testis barrier/Sertoli cell barrier, is also important to seclude advanced germ cells but its requirement in testis immune privilege needs further investigation. Testicular immune privilege is not permanent, as an effective immune response can be mounted against transplanted tissue, and bacterial/viral infections in the testis can be effectively eliminated. Overall, the cellular components control the fate of the immune response and can shift the response from immunodestructive to immunoprotective, resulting in immune privilege.

Immune regulation in the male genital tract

Spermatozoa are not produced until puberty, long after the establishment of tolerance to self-antigens. Therefore, sperm-specific antigens are immunogenic in men. Most men, however, do not produce antibodies to their own gametes. Development of mechanisms to prevent or limit autoimmune responses to spermatozoa were essential for preservation of reproductive capacity. Tight junctions between adjacent Sertoli cells, as part of the blood-testis barrier, prevent sperm-immune cell contact. In some portions of the genital tract this barrier is thin or incomplete. Immune mechanisms have evolved to actively suppress the autoimmune response to spermatozoa within the genital tract. Unlike in the circulation where CD(4+) helper T lymphocytes predominate, CD(8+) suppressor/cytotoxic T lymphocytes are the most prominant T cells in the epididymis and vas deferens. In addition, spermatozoa suppress pro-inflammatory lymphocyte immune responses, possibly by inducing production of anti-inflammatory cytokines. Antisperm antibody production is induced in the male genital tract when a local infection or disruption in the genital tract physical barrier leads to an influx of CD(4+) T cells. In response to induction of a productive immune response, two additional mechanisms downregulate humoral immunity within the genital tract. T lymphocytes possessing the gammasigma form of the antigen receptor (gammasigma T cells) are concentrated in the male genital tract and in semen. These cells become activated and proliferate in men with evidence of sperm autoimmunity. Activated gammasigma T cells inhibit production of antibodies by activated B lymphocytes, thereby limiting antisperm antibody production. Heat shock proteins (hsps) are also present in semen in association with infection and antisperm antibody formation. Hsp gene transcription leads to inhibition of transcription of the genes coding for pro-inflammatory cytokines and, conversely, to activation of gammasigma T cells. Activated gammasigma T cells also promote hsp synthesis. The mechanisms to inhibit immunity to sperm may hinder effective immune elimination of microoganisms in the male genital tract.

Regulatory T cells control tolerogenic versus autoimmune response to sperm in vasectomy

Vasectomy is a well accepted global contraceptive approach frequently associated with epididymal granuloma and sperm autoantibody formation. To understand the long-term sequelae of vasectomy, we investigated the early immune response in vasectomized mice. Vasectomy leads to rapid epithelial cell apoptosis and necrosis, persistent inflammation, and sperm granuloma formation in the epididymis. Vasectomized B6AF1 mice did not mount autoimmune response but instead developed sperm antigen-specific tolerance, documented as resistance to immunization-induced experimental autoimmune orchitis (EAO) but not experimental autoimmune encephalomyelitis. Strikingly, tolerance switches over to pathologic autoimmune state following concomitant CD4(+)CD25(+)Foxp3(+) regulatory T cell (Treg) depletion: unilaterally vasectomized mice produce dominant autoantibodies to an orchitogenic antigen (zonadhesin), and develop CD4 T-cell- and antibody-dependent bilateral autoimmune orchitis. Therefore, (i) Treg normally prevents spontaneous organ-specific autoimmunity induction by persistent endogenous danger signal, and (ii) autoantigenic stimulation with sterile autoinflammation can lead to tolerance. Finally, postvasectomy tolerance occurs in B6AF1, C57BL/6, and A/J strains. However, C57BL/6 mice resisted EAO after 60% Treg depletion, but developed EAO after 97% Treg reduction. Therefore, variance in intrinsic Treg function--a possible genetic trait--can influence the divergent tolerogenic versus autoimmune response to vasectomy.

Immunology of the Testis and Male Reproductive Tract

A large body of evidence points to the existence of a close, dynamic relationship between the immune system and the male reproductive tract, which has important implications for our understanding of both systems. The testis and the male reproductive tract provide an environment that protects the otherwise highly immunogenic spermatogenic cells and sperm from immunological attack. At the same time, secretions of the testis, including androgens, influence the development and mature functions of the immune system. Activation of the immune system has negative effects on both androgen and sperm production, so that systemic or local infection and inflammation compromise male fertility. The mechanisms underlying these interactions have begun to receive the attention from reproductive biologists and immunologists that they deserve, but many crucial details remain to be uncovered. A complete picture of male reproductive tract function and its response to toxic agents is contingent upon continued exploration of these interactions and the mechanisms involved.

Angio-proliferative lesions in a homosexual boar with features resembling Kaposi's sarcoma

Clinical, biopsy and necropsy studies of a homosexual boar revealed angio-proliferative lesions in the skin of the thigh, scrotum and the inguinal lymph node. Angiofibromas were identified in the dermis and subcutis of the thorax and mandible. The avidin-biotin-peroxidase complex technique demonstrated Factor VIII-related antigen as a marker for the neoplastic endothelial cells of the tumors. This boar also showed weight loss and lymphopenia. Explants of tumors were maintained in cultures for 22 passages and cultured cells produced tumors when injected subcutaneously into nude mice. No viral antigen was detected in the cultured tumor cells. Similarities and differences between the lesions in the boar and human Kaposi's sarcoma are discussed.

Semen alloantigens and lymphocytotoxic antibodies in AIDS and ICL

More than 90% of people with AIDS develop circulating immune complexes (CICs) and lymphocytotoxic antibodies (LCTAs). Animals infected with HIV, however, never display CICs or LCTAs, and remain healthy. Similarly, HIV-infected people who do not develop CICs or LCTAs also do not progress to AIDS. The appearance of CICs and LCTAs is, however, highly prognostic for AIDS and death. Since HIV infection does not, per se, lead to the development of CICs and LCTAs, other causes are likely. One such cause, for which both epidemiologic and experimental evidence exists, is semen. Semen components include sperm, seminal fluid, lymphocytes, and sometimes infectious agents, including HIV, mycoplasmas, and herpes and hepatitis viruses, all of which independently cause immune suppression. Extensive evidence demonstrates sperm (and various viruses) contains many proteins mimicking the CD4 protein of T-helper cells, while HIV, mycoplasmas, and seminal fluid mimic class II MHC proteins of other lymphocytes. We identify a large number of protein sequences that display such mimicry using computer homology searching, and demonstrate experimentally that sperm antibodies specifically precipitate antibodies against class II MHC mimics such as mycoplasmas, which in turn precipitate antibodies to lymphocyte antigens. These data prove that immunologic exposure to sperm and lymphocytes (as may occur in receptive anal intercourse, needle sharing, or blood transfusions) is theoretically capable of initiating lymphocytotoxic autoimmunity. Such autoimmunity may play a significant role in the pathogenesis of AIDS, and will need to be addressed clinically in high risk individuals regardless of HIV status and regardless of the success of anti-HIV prophylaxis and treatment.

Modulation of allo-immune responses in vivo and in vitro by sperm specific lactate dehydrogenase-C4

The role of sperm specific lactate dehydrogenase-C4 (LDH-C4) in allo-immune responses using mixed lymphocyte cultures (MLC) and cytotoxic T cell (CTL) generation in vitro and local graft versus host (LGVH) reaction and allograft enhancement in vivo has been ascertained. LDH was purified from testes (LDH-C4) and kidney (LDH-B4) of C57Bl/Ks mice. MLC and CTL were performed using C57Bl/Ks-anti A/J lymphocytes in presence of 10(-3)-1 micrograms LDH-B4 or LDH-C4 per culture. The MLC and CTL responses showed biphasic action depending on the dose of LDH-C4. Early MLC culture gave significantly low stimulation index at 10(-2)-10(-1) micrograms LDH-C4 as compared to non-treated control cultures. However, the MLC response in presence of LDH-C4 was not different from the LDH-B4 treated one which showed a similar biphasic trend. On the other hand, 51Cr release from YAC-222 target cells was practically abolished by LDH-C4 at 10(-3)-1(-1) micrograms, and this was strikingly different from LDH-B4 or non-treated cultures. LGVH reactivity as performed by using C57Bl/Ks lymphocytes along with LDH-C4 in (C57Bl/Ks x A/J) F1 hybrids indicated a suppression of stimulation index in primary and secondary (i.e. preimmunized in presence of LDH-C4 or LDH-B4) LGVH. Allograft enhancement of Sa I (A/J) in C57Bl/Ks mice in presence of LDH-C4, was delayed slightly but significantly during primary or secondary transplantation reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Species-specific effect of proteins secreted by cultured pre-pubertal rat Sertoli cells on natural killer cell activity

The effect of proteins secreted by cultured pre-pubertal rat Sertoli cells (pSCP) on natural killer (NK) cell activity of rat, mice and guinea pig splenocytes and human peripheral blood lymphocytes was estimated. The results indicate that pSCP inhibited, in a dose-dependent manner, NK cell activity of mice, guinea pig and human lymphocytes but did not suppress lysis of YAC-1 target cells by rat NK cells. Species-specific differences in the effect of pSCP on NK cell activity probably result from differences in the binding of proteins within the effector cells. These data indicate that in the pre-pubertal period of gonadal development immature Sertoli cells synthesize a factor/s which might contribute to the maintenance of specific testis immunological environment.

Suppressive effect of a mouse testicular extract on lymphocyte activation

The effect of mouse testicular extract (TE) on lymphocyte activation was investigated. TE, in the dose range 75-600 micrograms ml-1, suppressed significantly the blastogenic response of splenocytes to concanavalin A (Con-A), pokeweed mitogen (PWM), phytohaemagglutinin (PHA) and lipopolysaccharide (LPS). TE also suppressed the blastogenic response of B-cells to LPS and of T-cells to PHA in a dose-dependent manner as well as suppressing the mixed lymphocyte reaction (MLR). Pretreatment of splenocytes with TE did not however, completely suppress their blastogenic response to Con-A, when the treated cells were washed prior to culturing. Furthermore, TE did not inhibit the on-going blastogenesis of splenocytes that had been activated already with Con-A for 48 h. Splenocytes obtained from TE-treated mice remained capable of responding to Con-A stimulation, whereas they did not respond to listerial antigens when mice were immunized with Listeria monocytogenes together with TE. The effects of TE were enhanced significantly by heating to 100 degrees C, but were resistant to pronase, RNase and DNase. These results suggest that TE affects non-specifically the stage of lymphocyte sensitization to antigens or mitogens.

Lymphocyte subsets in the lymph nodes of rats with autoimmune orchitis

We determined temporal variations of cell subpopulations in the immunization draining lymph nodes during the development of an experimental autoimmune orchitis (EAO) induced in Wistar rats. A phenotypic characterization of T cells and their subsets (CD4+ and CD8+), B, and Ia+ cells was performed by immunofluorescent technique. At the end of the immunization period (30 days), rats injected with testicular homogenate plus adjuvants presented a considerable increase in absolute cell number but normal lymphocyte subset percentages. Testicular damage became evident at 50 days after the first immunization and increased its severity at 80 days: animals that developed EAO presented a lower number of CD8+ cells as compared with undamaged rats. This latter group showed a low CD4/CD8 ratio due to the high proportion of CD8+ cells, which could probably have a suppressor function. At 80 days massive testicular infiltration and decreased absolute cell number in lymph nodes suggest the possible migration of specific lymphocytes to the target organ.

Histogenesis of malignant melanoma of the skin: the role of lymphocytes in the transformation of tissue developmental units

It is proposed that the completion of both growth and differentiation, in highly specialized progressively evolving multicellular organisms, is achieved throughout two separated but sexually interacting populations of cells (bi-clonal model): 1) the germ line, seated in an obligatory axial position, required for the generation of cytoplasmic replicons, is the source of travelling vectors (spermatozoa, lymphocytes ...) endowed with these potentially transforming nucleoproteins. 2) The centrifugally growing somatic tissues subjected to mitotic senescence. The progressive loss of replicons probably triggers meiotic-like recombinations and differentiation in distal tissues. The shedding of axial replicons to distal meiotic targets seems to be instrumental in transformation, initiating both, embryogenesis and cancer. This theoretical approach is applied to the histogenetic model of malignant melanoma of the skin. In this setting, the axial population is identified as lymphocytes involved in a process of extrathymic maturation (lichenoid lesions), in the same field where melanoma would arise. Pagetoid nests of melanocytes are considered to be the expression of TDUs evolving in a distal population of senescent neurocristic cells. This situation establishes the likelihood of mixing between potentially transforming lymphocytes and the meiotic melanocytes resulting in a transformed hybrid, the earliest cellular expression of malignant melanoma.

Effects of mouse testicular extract on immunocompetent cells

We investigated mouse testicular extract (TE) to clarify its biological functions in reproductive immunity. TE, at concentrations of 50-300 micrograms/ml, enhanced macrophage activities of spreading, glucose consumption, and cytostasis against a susceptible tumor cell line. On the other hand, TE inhibited concanavalin A (Con A)-induced T-cell blastogenesis in the dose range of 10-600 micrograms/ml. To elucidate the origin of TE, W/Wv mice, which genetically lack germ cells, were used. TE obtained from W/Wv mice enhanced the spreadability of macrophages and inhibited Con A-induced blastogenesis of T cells. The enhancement of macrophage spreading was only achieved by the interstitial fluid (IF), while the suppression of Con A-induced T-cell responses was detected in seminiferous tubule fluid (STF) as well as in IF. TE did not affect listerial antigen-specific responses of lymphocytes in vitro. These results suggest that TE has the capacity to regulate the biological responses associated with reproduction.

Failure of sperm-induced immunosuppression: association with antisperm antibodies in women

The ability of husbands' sperm to inhibit proliferation of their wives' lymphocytes was measured. Seventeen of 27 sperm samples tested (63%) inhibited lymphocytes from responding to Candida antigens. Eleven of the 27 women (41%) had sera that were positive for antisperm antibodies; sperm from only four of their husbands (36%) were immunosuppressive. In contrast, 13 of the 16 women (81%) without antisperm antibodies had partners with suppressive sperm. Lymphocytes from four women with antisperm antibodies were inhibited by sperm from a fertile donor although not inhibited by their husband's sperm, whereas in three other antibody-positive women neither the husbands' nor donors' sperm were inhibitory. Antisperm antibodies in some women may arise as a consequence of a failure of sperm from their male partners to inhibit lymphocyte activation.

Perturbation of the idiotypic network. I. Induction with multiple alloantigen stimulation

The effect of hyperimmunization on the immune network with allostimulated syngeneic lymphocytes responding to different haplotypes was analyzed. Ten different haplotypes were used to stimulate syngeneic donor mice. Control mice were multiply immunized with incomplete Freund's adjuvant alone or with syngeneic mixed lymphocyte culture-generated lymphocytes. BALB/c mice were immunized consecutively with alloreactive blasts or allogeneically stimulated spleen cells at 10-day intervals. After a rest period of 2 months, the ratio of T helpers to T suppressors was determined by immunofluorescent staining. The functional network was probed by immunizing the mice with phosphorylcholine (PC) coupled to hemocyanin. The sera were analyzed for anti-PC antibodies and TEPC15 (T15) idiotypic expression. The results demonstrated (i) a decrease in the level of anti-PC antibody titer and T15 idiotypic expression; (ii) a decrease in the number of T helper cells and an increase in the number of T suppressor cells; (iii) a loss of PC epitope specificity; (iv) an increase of IgM antibodies expressing T15 without anti-PC specificity; and (v) an elevated level of preimmune lymphocyte proliferation and Ig secretion. These results reveal a functional network linkage in the regulation of alloreactivity and antigen response and show how repeated exposure to alloantigens can induce a perturbation of the idiotypic network controlling the response of a non-alloantigen-related BALB/c strain dominant idiotype (T15).

Mechanisms of active suppression of the immune response to spermatozoa

The production of autoantibodies to spermatozoa in males and isoantibodies in females is inhibited both by the physical isolation of spermatozoa from the systemic immune system and by active immunosuppression mechanisms. Lymphoid cells present in the epithelial lining of the rete testis, epididymis, and vas deferens, as well as the human ejaculate, are predominantly T suppressor/cytotoxic cells. Mononuclear cells derived from semen inhibit the in vitro activation of peripheral blood lymphocytes. Soluble specific T suppressor/cytotoxic cell activators in semen or on the sperm surface may be responsible for the predominance of this T cell subset in the male reproductive tract. The activation of T suppressor/cytotoxic cells following coitus may also limit the immune response to spermatozoa in females. Spermatozoa can also initiate immunosuppression, either by selectively inducing T suppressor cells or through the generation of activated complement components that block antibody production. Antisperm antibodies in sera from females may be associated with either a deficiency in the ability of their T suppressor/cytotoxic cells to be induced by factors in semen or by the occurrence in their husbands' ejaculates of microorganisms, antibodies, or other factors that induce T helper lymphocytes. Activated T cells produce interferon gamma, which induces Ia antigen expression on macrophages and allows the female's T helper cells to recognize processed sperm antigens. Recognition of the role of cell-mediated immune functions in the male and female genital tract identifies possible new target sites for the development of contraceptive agents.

Cell-mediated immunity in infertility

A role of cell-mediated immunity in immunologic infertility is indicated by a number of animal immunization studies and by reported clinical associations between cellular immune responses and infertility. Furthermore, recent technical advances in the field of cellular immunology have enabled advanced studies on the cellular and soluble mediators of cell-mediated immune responses and their interactions with reproductive processes. In this article we review some of the recent technical and conceptual advances in cellular immunology, the classic literature on cellular immune responses in infertility, and recent evidence that certain products of activated lymphocytes and macrophages significantly affect reproductive functions.

Reappraisal of AIDS--is the oxidation induced by the risk factors the primary cause?

The emergence of AIDS as a recognizable disease, its epidemiology, the clinical and laboratory data and the way in which they have been interpreted to deduce the currently acceptable hypothesis of its aetiology and mechanism of transmission are critically examined. There is no compelling reason for preferring the viral hypothesis of AIDS to one based on the activity of oxidizing agents. In fact, the latter is to be preferred, since unlike the viral hypothesis it leads to possible methods of prevention and treatment using currently available therapeutic substances.

The rejection of thyroid allografts in the ovine testis

The survival of thyroid autografts and allografts in the ovine testis has been investigated. Thyroid autografts survived and concentrated iodine 4 weeks after transplantation. Healthy colloid-containing follicles were found in the graft at this time, although no response of the grafts to a thyrotropin releasing hormone (TRH) challenge could be detected and there was no detectable basal thyroxine secretion into testicular venous blood or lymph. Thyroid allografts, however, were effectively rejected within 4 weeks of transplantation and did not concentrate iodine. No healthy tissue in the allografts could be found at 4 weeks after transplantation. Thus, in contrast to rodents and related species, the ovine testis does not appear to be an immunologically privileged site. This suggests that the immune privileged status of the rodent testis is not necessarily a general mammalian characteristic.

Androgens inhibit proliferation of human peripheral blood lymphocytes in vitro

The effect of sex hormones on human lymphocytes was examined in vitro on cell cultures of human peripheral blood mononuclear cells (HPBM). Cells were stimulated using T- and B-cell mitogens, and hormones in physiological (nM) or pharmacological (microM) concentrations were added. Proliferation was determined by measuring the incorporation of tritiated thymidine. It was found that both testosterone and dihydrotestosterone, in physiological concentrations, can attenuate DNA synthesis. The effect was dose dependent in that pharmacological concentrations of both testosterone and dihydrotestosterone caused a strong inhibitory effect on proliferation of in vitro cultured HPBM. However, cell cultures of a few individuals were insensitive to the androgens even at pharmacological concentrations. Also, no difference could be detected in the response between cultured cells of females and males. Although a slight reduction in antibody production was evident in pokeweed mitogen-stimulated cultures, in the presence of both testosterone and dihydrotestosterone, it was, however, not statistically significant.

Demonstration of spermatozoa in the lung of an AIDS patient

Using the DNA-binding fluorochrome, DAPI, spermatozoa and Pneumocystis carinii were easily demonstrated in postmortem lung sections of an AIDS patient. The possible practical significance of these findings is discussed.

Prostaglandin E2 administered via anus causes immunosuppression in male but not female rats: a possible pathogenesis of acquired immune deficiency syndrome in homosexual males

To explain a possible pathogenesis of acquired immune deficiency syndrome (AIDS) in homosexual males, we propose the following hypothesis. Prostaglandin E2 in human semen given via anus during anal intercourse may cause an immune dysregulation in the male semen recipients; this immunosuppressive effect of prostaglandin E2 may be one of the underlying factors that stimulate AIDS-associated virus infection or that trigger the latent AIDS-associated virus. This hypothesis is supported by the following experimental results. Anal infusion of prostaglandin E2 or D2 into male rats reduced in vitro responses of T lymphocytes to phytohemagglutinin. However, the T-cell response of female rats was not reduced significantly by the anal infusion of seminal prostaglandins.

Epididymal fluid macromolecules do not act as auto- or alloantigens

Because epididymal secretory glycoproteins form important functional associations with maturing spermatozoa, the possibility has been explored that epididymal antigens might be useful in contraceptive vaccine development. Male and female rabbits, hamsters, and rats were immunized for several weeks with epididymal fluid, initially either with complete Freund's adjuvant, or conjugated with glutaraldehyde. Some female rabbits were also immunized using albumin-free rabbit epididymal fluid. The sera of all the immunized animals were then examined for autogenous, allogeneic, or [in guinea pigs also] xenogeneic immune responses, using immunodiffusion and ELISA techniques. In each instance, xenogeneic immunization produced a marked antibody response. However, no animals developed any detectable antibody reactive with epididymal fluids following auto- or alloimmunization (ie with fluid from the same species), and they remained fertile even when immunized males were mated with immunized females. Furthermore, when female rabbits were immunized with ejaculated rabbit spermatozoa, they produced antibodies reactive only with the sperm homogenate, but not with any epididymal fluid component. These results indicate that macromolecules secreted by the epididymis, including those that associate with spermatozoa, do not act as auto- or alloantigens and, at present, would seem to have no immediate promise for contraceptive vaccine development in males or females.

The role of germinal epithelium and spermatogenesis in the privileged survival of intratesticular grafts

The testis is an immunologically privileged site. Since earlier studies excluded testicular steroid production as an essential factor, the present study evaluates the role of germ cells and spermatogenesis in the privileged survival of allografts within the testis. We used a Sertoli cell-only testis model and adolescent unilateral cryptorchidism in inbred rats to eliminate germ cells and spermatogenesis selectively. Parathyroid allografts were implanted into these sites, normal testes and beneath the renal capsule (a nonprivileged site) in appropriately matched controls. With at least 15 rats in each group, privileged allograft survival was shown to be unaffected by eliminating germ cells and spermatogenesis (p less than .005). Experimental evidence suggests the presence of an active process which incidentally permits privileged allograft survival within the testis, but which exists teleologically to protect the developing sperm from autoimmune attack. This is in addition to the passive anatomical separation provided by the blood-testis barrier. Our cumulative data strongly implicates the Sertoli cell in this process.

Increases in the numbers of immunoglobulin-secreting cells in lymph nodes responding to sperm and other stimuli: possible relationship to immunosuppression

It has been reported that, in early pregnancy in mice, there is an increase in the number of immunoglobulin-secreting cells in the lymph nodes which drain the uterus. This paper describes the results of further investigations provoked by interest in these early changes. Increases in the numbers of immunoglobulin-secreting cells were observed in syngeneically, but scarcely or not at all in allogeneically, mated mice. Increases were not observed in surgically sterilized female mice inseminated by normal males. However, subcutaneous injection of sperm provoked massive increases in the numbers of immunoglobulin-secreting cells in the lymph nodes draining the injection site. The changes were compared with those provoked by the injection of spleen cells and LPS. The results are discussed in relation to the nature of the interactions provoking the increases in the number of immunoglobulin-secreting cells and their possible relationship to immunosuppression, and the relative immunological unresponsiveness which the female shows to the challenge of inseminated sperm.

Current trends in antifertility vaccine research

We review the major advances that have recently occurred in the area of antifertility vaccines by examining the immunogenic potential of gamete, embryonic and placental antigens. In human trials using beta-human chorionic gonadotropin coupled with tetanus toxoid as the immunogen, the major problems with antifertility vaccines relate to specificity and maintaining an adequate antibody titer to disrupt gestation. Possible complications include cross-reaction with other body tissues, immune complex deposition, cytotoxicity, impaired immunologic tumor surveillance and nonreversibility.

A distinctive follicular hyperplasia in the acquired immune deficiency syndrome (AIDS) and the AIDS related complex. A pre-lymphomatous state for B cell lymphomas?

The histological features of a distinctive follicular hyperplasia observed in twenty-nine male patients with AIDS or the AIDS related complex are described. The group includes four patients with Kaposi's sarcoma, five with lymphoma, 16 with persistent generalized lymphadenopathy, and four with hemophilia. Histopathology is correlated with lymphocyte phenotyping and clinical findings and a model for the pathogenesis of this unique syndrome is presented.

Detection and characterization of immune complexes in the circulation of infertile women

The incidence of circulating immune complexes (CICs) was evaluated in sera from 39 female partners of infertile marriages and from 38 fertile women. Fifteen (38%) of the infertile women had CICs, as determined by the Raji cell assay, in levels ranging from 300 to 8000 micrograms/ml; whereas only 1 (3%) of the fertile women displayed CICs (P less than 0.001). Analysis of the CICs from nine of the women following polyethylene glycol precipitation and acid dissociation revealed that four contained C1q and three contained an antigen reactive with rabbit antibody to human spermatozoa. These latter three women all lacked free sperm antibody, as determined by enzyme-linked immunosorbent assay and agglutination. Thus, CICs are not uncommon as a manifestation of infertility in females. Their presence may lead to an underestimation of sperm antibody levels and may be indicative of underlying infection or autoimmunity.

Genetic control of humoral immunity to sperm acrosomal and cell surface antigens

We have defined the nature of genetic control of humoral immunity to sperm cell surface (TSDA) and acrosome (Ac) antigens. A sperm immunization dose that distinguishes between high-responder (BALB/c) and low-responder (B10) strains of mice was identified. B10 mice were unresponsive, whereas BALB/c and F1 hybrid mice responded to sperm of both parental strains. The ratio of nonresponder to responder mice in the B10 X F1 backcross and F1 X F1 inbred generations indicates anti-TSDA or anti-Ac antibody responsiveness is controlled through more than a single gene. The significant correlation found between the anti-TSDA and anti-Ac responses is consistent with the possibility that one or more genes controls antibody responsiveness against determinants common to both the Ac and sperm cell surface. Neither anti-TSDA nor anti-Ac antibody responses were linked to the I-A subregion of the responder H-2d MHC haplotype. In addition to a genetic difference in the control of humoral immunity to sperm, a difference in sperm immunogenicity among strains was observed. Antigens of the Ac of B10 sperm are more immunogenic than those of BALB/c sperm, and this trait is linked to the B10 Y chromosome.

Unregulated production of virus and/or sperm specific anti-idiotypic antibodies as a cause of AIDS

A network of idiotypic and anti-idiotypic antibodies is often suggested as the basis for cellular interactions that maintain a steady-state immunological equilibrium. This hypothesis proposes that repeated exposure to certain external antigens--ie, both viral and sperm--stimulates an unregulated production of a uniquely potent immunomodulating idiotypic antibody(ies). In a genetically predisposed individual, this particular antibody(ies), which is also an autoantibody(ies), results in a cellular immune deficiency. This disruption in the immune system permits opportunistic infection and thus the acquired immune deficiency syndrome. This hypothesis, which is readily testable and which does not involve a primary pathogen, can explain both the active induction of this disease in, as well as its passive transfer to, all at-risk populations.

Rectal insemination modifies immune responses in rabbits

Weekly deposition of pooled rabbit semen into the rectum in healthy male rabbits resulted in the appearance of immune complexes and antibodies to sperm and to peripheral blood lymphocyte antigens. It also led to a decreased ability to mount a humoral immune response to T lymphocyte-dependent antigens, keyhole limpet hemocyanin, and sheep red blood cells. These findings suggest that repeated rectal deposition of semen may compromise some aspects of the immune system.