Transfer of susceptibility to experimental autoimmune orchitis from responder to non-responder substrains of BALB/c mice.

Substrains of BALB/c mice differ in their susceptibility to experimental autoimmune orchitis (EAO), with BALB/cJ representative of the non-responders and BALB/cBy representative of the responders. We examined whether the susceptibility of these two substrains could be altered by reciprocal adoptive transfer of lymphoid cells. The cells transferred were of three types, normal spleen cells, T cell-enriched spleen and lymph node cells from mice immunized with testis homogenate (TH) in complete Freund's adjuvant (CFA) and given an extract of Bordetella pertussis (BP) and the latter cells activated by in vitro culture with TH antigen for 48 h. Controls were given buffer alone. Cell or buffer recipients were immunized with TH + CFA + BP three weeks later and examined for testicular histopathology 25-28 days after immunization. The cultured, immune T-enriched cells were consistently effective in transferring susceptibility from BALB/cBy to BALB/cJ. In the reverse experiments, non-responsiveness could be transferred from BALB/cJs to BALB/cBys most effectively with immune, non-cultured T-enriched cells. Transfer of cultured, immune T-enriched cells from BALB/cJs to other BALB/cJs had no significant effect on susceptibility to EAO. The results suggest that susceptibility to EAO in BALB/c mice depends on the T cell responses in the mice and not on differences at the level of the testis.

Role of testicular autoantigens and influence of lymphokines in testicular autoimmune disease.

The present data on testicular autoimmune disease suggest that CD4+ helper type T cells are responsible for adoptive transfer of murine experimental autoimmune orchitis (EAO). In passive EAO, the earliest lymphoid cell infiltration is confined to terminal segments of seminiferous tubules. Both orchitis and vasitis develop. In active EAO, any location in the testis is affected, frequently involving subcapsular seminiferous tubules. The location of maximum histopathology in passive EAO coincides with the site in the normal testis that expresses maximal Ia. Demonstration of IgG in the testis after immunization with testicular antigens or after transfer of sera from orchiectomized mice immunized with testis shows that autoantigens are present on the germ cells outside the Sertoli cell barrier, suggesting the existence of dynamic protective mechanisms against immune responses to the non-sequestered autoimmunogenic germ cells in normal individuals.

Inhibition of penetration of canine zonae pellucidae by homologous spermatoza in vitro using monoclonal antibodies raised against porcine zonae.

Ten monoclonal antibodies (MAbs) raised against porcine zonae pellucidae (PZP) were checked for their reactivity against zonae of other species. Two (MAbs A6 and C10) out of six MAbs checked reacted with canine zonae as ascertained by indirect immunofluorescence. One of these cross-reactive MAbs (A6) inhibited the penetration of canine ZP by canine spermatozoa in an in vitro assay by 62.5% and 22% at 10 micrograms/ml and 1 microgram/ml, concentration, respectively. Epitopes recognized by MAbs A6 and C10 are present on the 55-kDa glycoprotein of PZP as determined by Western blotting experiments. None of the ten anti-PZP MAbs reacted with zonae of the bonnet monkey, hamster or rabbit. Of the six MAbs checked, none showed cross-reactivity against mouse and cat zonae, and of four checked, none reacted with guinea pig zonae. Only one of the ten showed slight reactivity with human zonae.

The cellular immune response to immunization with zona pellucida antigens.

The cellular immune response of mice to porcine and rat zona pellucida and cynomolgus macaques to porcine zona pellucida antigens was evaluated. Mice mounted a vigorous cellular response to both antigens, as determined by the T cell proliferation response in vitro. There was poor cross-reactivity to murine zonae by T cells or serum antibodies from mice immunized with rat zona pellucida. Nevertheless, ovaries from the mice immunized with rat zona had significantly fewer antral follicles than adjuvant-treated controls, suggesting that the immune response to the zona antigen disrupted follicular development. T cells from two macaques that had been immunized with porcine zona pelludica proteins proliferated in vitro in response to this antigen. Both macaques also had strong antibody responses. The patterns of urinary steroid metabolites in these animals provided clear evidence of ovarian malfunction following immunization. The data indicate that a significant cellular immune response is generated upon immunization of animals with zona pellucida antigens regardless of whether the antigens are cross reactive with the host zona antigens. Whether impaired ovarian function and follicular development are related to the cellular response must be determined in future studies.

Evidence for active immunological regulation in prevention of testicular autoimmune disease independent of the blood-testis barrier.

It has long been considered that autoimmune disease of the testis is prevented by sequestration of testis-specific autoantigens on germ cells behind the blood-testis (BT) barrier. However, we now have evidence that not all such antigens are sequestered. Some appear to reside on germ cells in the basal compartment of the seminiferous tubule where they are accessible to antibodies and to circulating activated T cells. Mice immunized with syngeneic testis homogenate are found to have immunoglobulin G (IgG) bound to cells in the basal compartment before onset of orchitis. This IgG is absorbed from circulation by the testis and, therefore, found only in the serum of mice orchiectomized before immunization. When the IgG is eluted from the testis, it is found to react preferentially with testicular cells enriched in preleptotene spermatocytes. T cells from mice immunized with testis can be transferred to naive syngeneic mice where they infiltrate the testis to cause orchitis. This implies that the BT barrier does not need to be breached directly for specific T cells to have access to testicular autoantigens on antigen presenting cells. Thus, active systemic and/or local immunoregulatory mechanisms must operate to prevent testicular autoimmune disease. These mechanisms may operate at the level of suppressor T cells, nonspecific suppression in the local environment of the testis, antigen presentation in the testis, or lymphocyte trafficking in the testis. These mechanisms probably operate only on the afferent limb of the immune response since they are overridden and orchitis occurs once testis-specific activated T cells are generated.

Ovarian histopathology of bitches immunized with porcine zonae pellucidae.

The ovarian histopathology of bitches immunized with crude (cPZP) or partially purified (pPZP) porcine zona pellucida proteins was examined in order to determine the cause of abnormal estrous cycles. The majority of immunized bitches had ovarian cytes. Those immunized with cPZP had follicular cysts lined with a thin layer of granulosa cells, while in those immunized with pPZP, the cysts were lined by a basement membrane with a clump of luteinized cells. In two bitches immunized with cPZP, oocytes were present only in primordial follicles. Similar abnormalities were not found in a bitch immunized with human serum albumin or in 12 untreated bitches. Oocytes flushed from the oviducts of mated, immunized bitches were degenerating, which may have been a primary cause of infertility in such bitches. Ovaries studied 2-6 weeks after immunization showed no loss of gap junctional communication between oocytes and granulosa cells, nor was any inflammatory reaction seen. IgG was bound to the zona as revealed by fluoresceinated protein A staining of frozen sections of those ovaries. Abnormal estrous cycles in PZP-immunized bitches appear to result from follicular dysgenesis or cyst formation, but the etiology of these conditions is unresolved.

Primate response to immunization with a homologous zona pellucida peptide.

Development of a contraceptive vaccine using zona pellucida (ZP) antigens has been hampered by the observation that the immune response to the antigens results in altered ovarian function and depletion of the follicular pool of oocytes. The amino acid sequences of many ZP proteins have been determined in the past decade allowing study of fully synthetic peptide immunogens based on these ZP sequences. Such immunogens permit a precisely targeted response. The non-human primate is the best model for predicting how women may respond to ZP peptide vaccines. Cynomolgus macaques (Macaca fascicularis) have been immunized with synthetic peptides comprising a human ZP3 epitope and a macaque homologue of the same epitope. In both studies, immune response to the peptides was initiated, and infertility was accompanied by normal ovarian function.

Response of cynomolgus macaques to immunization against a synthetic peptide from the human zona pellucida.

This study tested immunogenicity of a synthetic peptide hZP3(327-341) from a human zona pellucida (ZP) glycoprotein. After antibody response to various peptide-carrier conjugates was assessed in mice, two female cynomolgus macaques were immunized with the peptide conjugated to keyhole limpet hemocyanin (KLH). A control macaque was immunized with KLH. The peptide was immunogenic in both species, and included both B and T cell epitopes since low to moderate titers of peptide-specific antibodies and a T cell proliferative response were measured. Profiles of ovarian steroid metabolites indicated unchanged ovarian function in the macaques, but only the control conceived when bred. Ovarian histology was normal except that immunoglobulin was bound to ZP in follicles of the peptide-immune macaques. ZP from these females bound sperm and induced acrosome reactions at rates equal to those of an untreated control. The results support the feasibility of an immunocontraceptive vaccine based on autologous ZP peptides.

Infertility in bitches induced by active immunization with porcine zonae pellucidae.

In a study designed to evaluate the contraceptive potential of anti-egg zona pellucida immunization, bitches were injected with isolated and solubilized zonae pellucidae of either the pig or the dog in saline and Freund's adjuvant or with saline and adjuvant alone (controls). They were boosted monthly, and serum samples were collected before the first injection and 10 days after each injection. The titers of anti-zona pellucida antibodies in each serum sample were measured by treating fresh canine oocytes with the serum, then evaluating antibody binding as indicated by indirect immunofluorescence, precipitation of the zona surface, and penetrability of the zonae by spermatozoa in vitro. The bitches were bred when they came into estrus. All three bitches immunized with porcine zonae developed high titers (1:10,000 or more by indirect immunofluorescence) of antibodies that cross-reacted with canine zonae to cause precipitation of the zona surface both in vivo and in vitro and that completely inhibited penetration of the zonae by spermatozoa in vitro. The two bitches immunized with canine zonae developed only low titers, and their sera had little or no effect on treated zonae. The two control bitches did not develop anti-zona antibody. None of the bitches immunized against porcine zonae became pregnant when bred, but one bitch immunized against canine zonae and one control did become pregnant. The bitches immunized with porcine zonae had somewhat abnormal cycles for unknown reasons. Thus, we could not establish with certainty whether the infertility resulted from specific interference with fertilization, as in vitro, or from alterations in ovarian function, or both.

Activation requirements of donor T cells and host T cell recruitment in adoptive transfer of murine experimental autoimmune orchitis (EAO).

The relative roles of donor and host T lymphocytes and the T cell activation requirements in adoptive transfer of experimental autoimmune orchitis (EAO) in (C57BL/6 x A/J)F1 mice were investigated in order to gain an understanding of the pathogenesis of this disease. Depletion of T cell subsets in recipients by adult thymectomy and treatment with monoclonal antibodies against CD4 or CD8 had no effect on the incidence of EAO following adoptive transfer of activated T cells from donors immunized with testis homogenate (TH) and adjuvants. In contrast, such depletion of CD4+ T cells inhibited development of EAO in actively immunized mice. Thus, CD4+ cells are required for induction of EAO, but donor CD4+ cells are sufficient by themselves without a comparable contribution from the recipient. Adoptive transfer of EAO required that donor splenic and lymph node T cells be activated in vitro before transfer. We found that exposure to antigen (TH) for as little as 4 hr allowed EAO to occur in 25% of recipients, and by 24 hr the cells were fully competent to induce disease. Proliferation of the cells could not be measured until 2 days later. In serial double-transfer experiments, it was found that the cells must be cultured with TH before each transfer in order for the secondary recipients to develop EAO. However, it was not necessary for the transferred T cells to "see" antigen in vivo in the primary recipients, since transfer to castrated primary recipients had no effect on EAO incidence in secondary recipients. Lymphocytes isolated from diseased testes of immunized donors were competent to transfer EAO without activation in vitro, suggesting that, unlike spleen and lymph node cells, these orchitic lymphocytes were already capable of trafficking to the testis.

Induction of acrosome reactions of canine sperm by homologous zona pellucida.

In this study the induction of the acrosome reaction of canine sperm by homologous zona pellucida (ZP) was examined. Twelve semen samples obtained from 6 normal beagle dogs were evaluated after sperm incubation in vitro with canine capacitation medium (CCM). Washed sperm were preincubated at 37 degrees C in 5% CO2 in air for 4 and 7 h prior to experimental treatment. Sperm were co-incubated for 1 min with intact oocytes collected from canine ovaries. Half of the oocytes were then fixed, and the bound sperm were assessed for acrosome reactions through use of a polyclonal antisperm antiserum and indirect immunofluorescence. The remaining oocytes were incubated in sperm-free medium for an additional 1-h period, and the acrosomal status of sperm bound to the ZP was evaluated similarly. The percentage of acrosome-reacted sperm on the ZP increased significantly during the 1-h incubation period. In other experiments, capacitated canine sperm were incubated with heat-solubilized ZP for 1 h and their acrosomal status was determined using fluoresceinated Pisum sativum lectin. The percentages of acrosome-reacted sperm increased significantly in ZP solution compared with controls. These data demonstrate that intact and solubilized canine ZP are capable of inducing acrosome reactions of canine sperm.

Fertility control in the bitch by active immunization with porcine zonae pellucidae: use of different adjuvants and patterns of estradiol and progesterone levels in estrous cycles.

To determine the changes in patterns of 17 beta-estradiol and progesterone levels underlying abnormal cycles in bitches immunized with solubilized crude porcine zonae pellucidae (cPZP), to attempt to circumvent these problems by immunizing with a purified zona fraction (pPZP), and to test the effectiveness of different adjuvants, bitches were immunized with cPZP or pPZP 2-6 times with no adjuvant, Freund's adjuvant, alum adjuvant, or the adjuvant CP-20,961. The bitch immunized without adjuvant had a low titer with a normal cycle and fertility. Immunization with cPZP and adjuvant produced moderate to high titers of antizona antibodies and infertility. Bitches with high titers experienced abnormal estrous cycles. Estradiol rose during proestrus, but instead of falling sharply in early estrus as in controls, it remained elevated. Progesterone did not rise. The moderate-titered bitches had normal cycles and steroid patterns. Bitches immunized with pPZP had moderate titers. Cycles were normal after 3 injections, but after 6 injections one bitch had an abnormal cycle. One pPZP-immunized bitch remained fertile but the others were infertile. Alum was the mildest adjuvant, causing no injection site lesions, but the highest titers occurred with Freund's and CP-20,961 adjuvants. All three adjuvants induced titers sufficient to inhibit fertility. Infertility in bitches immunized with PZP may be due to prevention of zona penetration, because their antisera inhibited zona penetration of oocytes by spermatozoa in vitro. However, alterations in ovarian function preventing ovulation and luteinization could be involved in high-titered bitches.

Distribution of histopathology and Ia positive cells in actively induced and passively transferred experimental autoimmune orchitis.

Histopathology in testes from mice with actively induced experimental orchitis (EAO) (active EAO) and those from recipients of testis-sensitized lymphocytes (passive EAO) had different distributions. In passive EAO, maximum orchitis existed in the straight tubules, rete testis, and ductus efferentes, obstruction of which led to extreme dilatation of seminiferous tubules. Unusual intralymphatic granulomata also resulted in dilated testicular lymphatics. In active EAO, maximum orchitis affected seminiferous tubules under the testicular capsule, away from the rete testes. Vasitis was common and occurred in both active and passive EAO. In normal testes, IA+ F4/80+ cells were sparse but formed a cuff around the straight tubules. After immunization with testis in adjuvant or with adjuvant alone, the number, size, and staining intensity of IA+ cells increased dramatically beginning on day 5, 7 days before disease onset. Simultaneously, epithelial cells confined to the ductus efferentes became Ia+. Although recipients of sensitized lymphocytes also developed epithelial Ia in the ductus efferentes, they did not show changes in testicular interstitial Ia+ cells. Our findings indicate that testicular autoantigens are not completely sequestered, but are accessible to and can react with passively transferred immune lymphocytes in well-defined regions of the germ cell compartment. These regions coincided to a large extent with maximum expression of periductal or epithelial Ia. Changes in Ia+ cells in the testis, which are inducible by adjuvants and precede orchitis, may account in part for the different distribution of histopathology of active EAO.

Adoptive transfer of murine autoimmune orchitis to naive recipients with immune lymphocytes.

A protocol was developed for reproducibly transferring experimental autoimmune orchitis (EAO) to naive recipient mice. Cell donors were (C57BL/6 x A/J)F1 mice immunized about 14 days earlier with mouse testicular homogenate with Freund's adjuvant and an extract of Bordetella pertussis. Lymphocytes from lymph nodes and spleens were equally capable of transferring disease. As few as 5 X 10(6) cells were able to transfer EAO, which began on Day 5-7 after transfer. Infiltrate of lymphocytes and macrophages in the region of the rete testis and straight tubules was the most reproducible early lesion, suggesting that this is the initial site of T cell-antigen interaction. It was not necessary to use both Mycobacteria and B. pertussis adjuvants in donor immunization to achieve transfer of EAO. Disease transfer was antigen specific since only cells from donors immunized with TH could transfer disease. In vitro stimulation of the cells with testicular antigens and/or concanavalin A was a prerequisite to successful transfer of EAO, which was dependent on the presence of L3T4+ T cells since depletion of these cells greatly diminished EAO in recipients and the lymphocyte proliferation response to testicular antigens. Disease did not depend on an antibody response by the recipients. The results imply that effector cells, once generated by immunization and fully activated or selected by in vitro stimulation, can home to specific locations in the testis, locate relevant autoantigens, and cause disease.

Immunization of male but not female mice with the sperm-specific isozyme of lactate dehydrogenase (LDH-C4) impairs fertilization in vivo.

The goals of this study were to determine the site at which fertility is impaired in mice immunized with LDH-C4 and to determine whether immunization of both males and females would have a greater antifertility effect than immunization of one sex alone. Mice were immunized with LDH-C4 in two systemic doses in Freund's adjuvants and two gastric doses in bicarbonate buffer. The presence of anti-LDH-C4 antibodies in uterine fluid was confirmed. Male and female mice were assigned to four blocks in which either the males, the females, both, or neither were immunized. Oviducts were viewed directly 1 h after mating for the presence of sperm. No significant effect of immunization on sperm transport to the oviduct could be demonstrated. Fertilization was evaluated 4 h after mating. It was found that immunization of males, but not females, impaired fertilization (19.6% versus 50.8% of the oocytes penetrated in 17 and 19 females, respectively). Orchitis was found histologically in 43.8% of the immunized males and 10% of the control males.

Comparison of a fluoresceinated lectin stain with triple staining for evaluating acrosome reactions of dog sperm.

In this study a technique which utilized a fluoresceinated lectin and a fluorescent supravital stain was compared with the conventional triple stain technique for evaluating the viability and acrosomal status of dog sperm. Ten semen samples obtained from 6 normal beagle dogs were evaluated after incubation in vitro with canine capacitation medium. Sperm viability and acrosomal status were assessed at 0, 4, and 7 hours of incubation. Both staining techniques were capable of detecting the increase in spontaneous acrosome reactions which occurs during in vitro capacitation of dog sperm. High positive correlations were observed between the fluorescent stain and the triple stain in the mean values for the percentage of viable sperm and for the percentage of acrosome-reacted sperm among the viable sperm (r = 0.91, r = 0.97, respectively). However, the fluorescent staining techniques could be carried out much more rapidly than the triple stain technique, and the slides prepared with fluorescent stain were more easily scored because of the higher intensity and greater consistency of staining. These characteristics make the fluoresceinated lectin and the fluorescent supravital stain superior for evaluating acrosome reactions and viability of dog sperm.