Aspermatogenesis in the guinea pig induced by testicular tissue and adjuvants

Pathomechanisms of Autoimmune Based Testicular Inflammation

Infection and inflammation of the male reproductive tract are relevant causes of infertility. Inflammatory damage occurs in the special immunosuppressive microenvironment of the testis, a hallmark termed testicular immune privilege, which allows tolerance to neo-antigens from developing germ cells appearing at puberty, long after the establishment of systemic immune tolerance. Experimental autoimmune orchitis (EAO) is a well-established rodent model of chronic testicular inflammation and organ specific autoimmunity that offers a valuable in vivo tool to investigate the pathological and molecular mechanisms leading to the breakdown of the testicular immune privilege. The disease is characterized by the infiltration of the interstitium by immune cells (mainly macrophages, dendritic cells, and T cells), formation of autoantibodies against testicular antigens, production of pro-inflammatory mediators such as NO, MCP1, TNFα, IL6, or activins and dysregulation of steroidogenesis with reduced levels of serum testosterone. EAO leads to sloughing of germ cells, atrophic seminiferous tubules and fibrotic remodeling, parameters all found similarly to changes in human biopsies from infertile patients with inflammatory infiltrates. Interestingly, testosterone supplementation during the course of EAO leads to expansion of the regulatory T cell population and inhibition of disease development. Knowledge of EAO pathogenesis aims to contribute to a better understanding of human testicular autoimmune disease as an essential prerequisite for improved diagnosis and treatment.

Infectious, inflammatory and 'autoimmune' male factor infertility: how do rodent models inform clinical practice?

BACKGROUND

Infection and inflammation of the reproductive tract are significant causes of male factor infertility. Ascending infections caused by sexually transmitted bacteria or urinary tract pathogens represent the most frequent aetiology of epididymo-orchitis, but viral, haematogenous dissemination is also a contributory factor. Limitations in adequate diagnosis and therapy reflect an obvious need for further understanding of human epididymal and testicular immunopathologies and their contribution to infertility. A major obstacle for advancing our knowledge is the limited access to suitable tissue samples. Similarly, the key events in the inflammatory or autoimmune pathologies affecting human male fertility are poorly amenable to close examination. Moreover, the disease processes generally have occurred long before the patient attends the clinic for fertility assessment. In this regard, data obtained from experimental animal models and respective comparative analyses have shown promise to overcome these restrictions in humans.

OBJECTIVE AND RATIONALE

This narrative review will focus on male fertility disturbances caused by infection and inflammation, and the usefulness of the most frequently applied animal models to study these conditions.

SEARCH METHODS

An extensive search in Medline database was performed without restrictions until January 2018 using the following search terms: 'infection' and/or 'inflammation' and 'testis' and/or 'epididymis', 'infection' and/or 'inflammation' and 'male genital tract', 'male infertility', 'orchitis', 'epididymitis', 'experimental autoimmune' and 'orchitis' or 'epididymitis' or 'epididymo-orchitis', antisperm antibodies', 'vasectomy'. In addition to that, reference lists of primary and review articles were reviewed for additional publications independently by each author. Selected articles were verified by each two separate authors and discrepancies discussed within the team.

OUTCOMES

There is clear evidence that models mimicking testicular and/or epididymal inflammation and infection have been instructive in a better understanding of the mechanisms of disease initiation and progression. In this regard, rodent models of acute bacterial epididymitis best reflect the clinical situation in terms of mimicking the infection pathway, pathogens selected and the damage, such as fibrotic transformation, observed. Similarly, animal models of acute testicular and epididymal inflammation using lipopolysaccharides show impairment of reproduction, endocrine function and histological tissue architecture, also seen in men. Autoimmune responses can be studied in models of experimental autoimmune orchitis (EAO) and vasectomy. In particular, the early stages of EAO development showing inflammatory responses in the form of peritubular lymphocytic infiltrates, thickening of the lamina propria of affected tubules, production of autoantibodies against testicular antigens or secretion of pro-inflammatory mediators, replicate observations in testicular sperm extraction samples of patients with 'mixed atrophy' of spermatogenesis. Vasectomy, in the form of sperm antibodies and chronic inflammation, can also be studied in animal models, providing valuable insights into the human response.

WIDER IMPLICATIONS

This is the first comprehensive review of rodent models of both infectious and autoimmune disease of testis/epididymis, and their clinical implications, i.e. their importance in understanding male infertility related to infectious and non-infectious/autoimmune disease of the reproductive organs.

Immunocontraceptive target repertoire defined by systematic identification of sperm membrane alloantigens in a single species

Sperm competence in animal fertilization requires the collective activities of numerous sperm-specific proteins that are typically alloimmunogenic in females. Consequently, sperm membrane alloantigens are potential targets for contraceptives that act by blocking the proteins' functions in gamete interactions. Here we used a targeted proteomics approach to identify the major alloantigens in swine sperm membranes and lipid rafts, and thereby systematically defined the repertoire of these sperm-specific proteins in a single species. Gilts with high alloantibody reactivity to proteins in sperm membranes or lipid rafts produced fewer offspring (73% decrease) than adjuvant-only or nonimmune control animals. Alloantisera recognized more than 20 potentially unique sperm membrane proteins and five sperm lipid raft proteins resolved on two-dimensional immunoblots with or without prior enrichment by anion exchange chromatography. Dominant sperm membrane alloantigens identified by mass spectrometry included the ADAMs fertilin α, fertilin ß, and cyritestin. Less abundant alloantigens included ATP synthase F1 β subunit, myo-inositol monophosphatase-1, and zymogen granule membrane glycoprotein-2. Immunodominant sperm lipid raft alloantigens included SAMP14, lymphocyte antigen 6K, and the epididymal sperm protein E12. Of the fifteen unique membrane alloantigens identified, eleven were known sperm-specific proteins with uncertain functions in fertilization, and four were not previously suspected to exist as sperm-specific isoforms. De novo sequences of tryptic peptides from sperm membrane alloantigen "M6" displayed no evident homology to known proteins, so is a newly discovered sperm-specific gene product in swine. We conclude that alloimmunizing gilts with sperm membranes or lipid rafts evokes formation of antibodies to a relatively small number of dominant alloantigens that include known and novel sperm-specific proteins with possible functions in fertilization and potential utility as targets for immunocontraception.

Pharmacokinetic and Toxicological Evaluation of a Zinc Gluconate-Based Chemical Sterilant Using In Vitro and In Silico Approaches

Sclerosing agents as zinc gluconate-based chemical sterilants (Infertile®) are used for chemical castration. This solution is injected into the animal testis, but there are not enough evidences of its safety profiles for the receivers. The present work aimed to establish the pharmacokinetics and toxicological activity of Infertile, using in vitro and in silico approaches. The evaluation at the endpoint showed effects in a dose-dependent manner. Since necrosis is potentially carcinogenic, the possible cell death mechanism could be apoptosis. Our data suggested that Infertile at 60 mM presented risk for animal health. Even though Infertile is a licensed product by the Brazilian Ministry of Agriculture, Livestock and Supply, it presented a high mutagenic potential. We suggest that the optimal dose must be less than 6 mM, once, at this concentration, no mutagenicity or genotoxicity was observed.

Development of a lipopolysaccharide (LPS)-supplemented adjuvant and its effects on cell-mediated and humoral immune responses in male rats immunized against sperm

Supplementation with lipopolysaccharide (LPS) from non-pathogenic Escherichia coli was found to enhance the adjuvant effects of a veterinary vaccine adjuvant (ISA 71VG^®). Sperm immunization using 71VG as an adjuvant in the immature period induced infertility in 25% of male rats, whereas this increased to 62.5% after immunization with 71VG + LPS or Freund′s complete adjuvant (FCA). Mean testicular weight of non-sterile males in the 71VG + LPS group was significantly lower than that in the 71VG or FCA group. Histological examination of testicular tissue from sterile males demonstrated severe impairment of spermatogenesis due to experimental autoimmune orchitis, a cell-mediated autoimmune condition. The serum anti-sperm titer was elevated in the three sperm-immunized groups relative to male rats treated with adjuvant alone, but the titer was higher in the 71VG + LPS and FCA groups than in the 71VG group. We consider that this LPS-supplemented adjuvant stimulates both humoral and cell-mediated immune responses to an extent comparable to FCA.

Intratesticular and intraepididymal injections to sterilize male cats

Aim and rationale:

The aim of intratesticular and intraepididymal injections is to provide an inexpensive non-surgical method for sterilizing tom cats. Intratesticular and intraepididymal injections have been studied for decades and warrant continued investigation. While both methods result in azoospermia, intratesticular injection of sclerosing agents induces orchitis, resulting in decreased spermatogenesis, whereas intraepididymal injection blocks sperm transport but does not alter spermatogenesis.

Evidence base:

Sclerosing agents that have been used effectively for intratesticular injections in cats include calcium chloride dihydrate and zinc gluconate. For sclerosis by intraepididymal injections, chlorhexidine digluconate has been used successfully in cats. The volume, formulation and concentration of sclerosing agents for intratesticular and intraepididymal injections in cats have not been standardized.

Challenges:

Neither intratesticular nor intraepididymal injections entirely eliminate gonadal testosterone production, which may be undesirable for pet cats and therefore may restrict the application of this method of sterilization to feral cats with limited human contact. In addition, both methods may require sedation or general anesthesia, leading some to support routine castration over these non-surgical methods. Lastly, even if the technique is successful in inducing permanent sterility, normal fertility may persist in treated males for 1–2 months after treatment because of sperm present within the epididymis and vas deferens.

A dose-finding, long-term study on the use of calcium chloride in saline solution as a method of nonsurgical sterilization in dogs: evaluation of the most effective concentration with the lowest risk

Background

Canine overpopulation is a global issue with serious health and welfare implications. Nonsurgical methods of sterilization could yield positive impacts on this problem, but no long-term data on such methods are available. The objective of the current investigation was to determine the effects of intratesticular injections of calcium chloride dihydrate (CaCl₂) in saline in dogs over a one year period. Five concentrations (0%, 10%, 20%, 30%, 60%) of CaCl₂ in saline were administered via intratesticular injection to groups of 10 dogs each. Total sperm count and motility, blood levels of testosterone, and side effects were examined at 0, 2, 6, and 12 months post-injection (PI). Testicular size and semen volume were examined at 0 and 12 months PI.

Results

Total sperm count, semen volume and testosterone showed significant dose-dependent decreases upon treatment with 10%-60% CaCl₂ compared with either the control group (0% CaCl₂) or baseline for each treatment group. Azoospermia was achieved for at least 12 months PI in 60% and 80% of treated dogs after administration of a 10% and 20% CaCl₂, respectively. Treatment with 30% or 60% CaCl₂ resulted in azoospermia in 100% of dogs, but more side effects were observed, while no side effects were noticed at lower doses. For each treatment group, testosterone levels had decreased an average of 35%-70% at 6 months following treatment. However, testosterone levels rebounded by the 12-month time point in all groups except the highest dosage group (60% CaCl₂), which remained at the low end of physiological range throughout the study. Sperm motility dropped to zero or near zero in all dogs treated with CaCl₂. Testicular size was significantly smaller at 12 months PI for all groups when compared to baseline.

Conclusions

This first long-term study confirms reports of the efficacy of CaCl₂ sterilization. However, at dosages free of adverse events, calcium chloride in saline may not provide permanent sterilization as previously believed. Future work should explore optimized solvents to increase the permanence of the well-tolerated 20% formulation.

Immunologic and testicular response in guinea pigs after unilateral traumatic orchitis

An acute and intense trauma was inflicted in one of the testes of adult guinea pigs. The immunological response and histological changes developed both in the injured and contralateral glands were studied at different intervals of time. It was observed: 1) Necrotic seminiferous tubules and a granulomatous cell reaction were seen in the injured gonad at 15 days. This was followed by a reduction of the mononuclear cell infiltration at 48 days. Finally a fibrotic tissue replaced the damaged areas at around 100 days. 2) Foci showing the classical picture of immunologic orchitis appeared in the contralateral gland at 15 and 48 days. Less frequent lesions were detected in the final period of the experiment. 3) These lesions were accompanied by cellular immunity detectable by the macrophage migration inhibition test at 15 and 48 days. With the exception of cytophilic activity also detected in same periods, no antibodies of hemagglutinating and sperm-agglutinating types could be found.

Defects in the regulatory clearance mechanisms favor the breakdown of self-tolerance during spontaneous autoimmune orchitis

We identified aberrations leading to spontaneous autoimmune orchitis (AIO) in mink, a seasonal breeder and natural model for autoimmunity. This study provides evidence favoring the view that a malfunction of the clearance mechanisms for apoptotic cell debris arising from imbalances in phagocyte receptors or cytokines acting on Sertoli cells constitutes a major factor leading to breakdown of self-tolerance during spontaneous AIO. Serum anti-sperm antibody titers measured by ELISA reflected spermatogenic activity without causing immune inflammatory responses. Orchitic mink showed excess antibody production accompanied by spermatogenic arrest, testicular leukocyte infiltration, and infertility. AIO serum labeled the postacrosomal region, the mid and end piece of mink sperm, whereas normal mink serum did not. Normal serum labeled plasma membranes, whereas AIO serum reacted with germ cell nuclei. Western blot analyses revealed that AIO serum reacted specifically to a 23- and 50-kDa protein. The number of apostain-labeled apoptotic cells was significantly higher in orchitic compared with normal tubules. However, apoptosis levels measured by ELISA in seminiferous tubular fractions (STf) were not significantly different in normal and orchitic tubules. The levels of CD36, TNF-alpha, TNF-alpha RI, IL-6, and Fas but not Fas-ligand (L), and ATP-binding cassette transporter ABCA1 were changed in AIO STf. TNF-alpha and IL-6 serum levels were increased during AIO. Fas localized to germ cells, Sertoli cells, and the lamina propria of the tubules and Fas-L, to germ cells. Fas colocalized with Fas-L in residual bodies in normal testis and in giant cells and infiltrating leukocytes in orchitic tubules.

Breaking ignorance: the case of the brain

Immunological self-tolerance is maintained through diverse mechanisms, including deletion of autoreactive immune cells following confrontation with autoantigen in the thymus or in the periphery and active suppression by regulatory cells. A third way to prevent autoimmunity is by hiding self tissues behind a tissue barrier impermeable for circulating immune cells. The latter mechanism has been held responsible for self-tolerance within the nervous tissue. Indeed, the nervous tissues enjoy a conditionally privileged immune status: they are normally unreachable for self-reactive T and B cells, they lack lymphatic drainage, and they are deficient in local antigen-presenting cells. Yet the immune system is by no means fully ignorant of the nervous structures. An ever-growing number of brain specific autoantigens is expressed within the thymus, which ensures an early confrontation with the unfolding T cell repertoire, and there is evidence that B cells also contact CNS-like structures outside of the brain. Then pathological processes such as neurodegeneration commonly lift the brain's immune privilege, shifting the local milieus from immune-hostile to immune-friendly. Finally, brain-reactive T cells, which abound in the healthy immune repertoire, but remain innocuous throughout life, can be activated and gain access to their target tissues. On their way, they take an ordered migration through peripheral lymphoid tissues and blood circulation, and undergo a profound reprogramming of their gene expression profile, which renders them fit to enter the nervous system and to interact with local cellule elements.

Non-surgical methods of contraception and sterilization

The Humane Society of the United States estimates that each year between 8 and 10 million dogs and cats enter shelters and 4-5 million of these animals are euthanized due to lack of homes. Many veterinarians within the United States recommend surgical sterilization for population control in dogs and cats. However, there are non-surgical methods to control reproduction. Pharmacologic methods of contraception and sterilization can be safe, reliable and reversible. Hormonal treatments using progestins, androgens, or gonadotropin releasing hormone (GnRH) analogs act to either directly block reproductive hormone receptor-mediated events, or indirectly block conception via negative feedback mechanisms. Immunocontraception, via vaccination against GnRH, the luteinizing hormone receptor or zona pellucida proteins, is also possible. Intratesticular or intraepididymal injections provide a method for non-surgical sterilization of the male dog and cat. Additional methods have been employed for mechanical disruption of fertility including intravaginal and intrauterine devices and ultrasound testicular ablation. Alternative approaches to surgical sterilization will be reviewed.

Aspermatogenesis, anaphylaxis, and cutaneous sensitization induced in the guinea pig by homologous testicular extract

Guinea pig testicles were extracted with acetic acid; the extract was purified by removing material in consecutive precipitations with 30 per cent saturated ammonium-sulfate, trichloracetic acid, and chloroform. The solution so purified, when administered with complete adjuvants, was highly active in inducing impairment of spermatogenesis in guinea pigs. The activity resisted autoclaving at 15 pounds' pressure for 20 minutes, proteolytic enzymes, and formamide. Anaphylactic shock and cutaneous reaction to the purified homologous extract occurred in guinea pigs sensitized by the extract combined with adjuvants. For the production of aspermatogenesis it was essential to incorporate killed mycobacteria into the water-in-oil emulsion containing the antigen; but anaphylactic sensitization did not require the presence of mycobacteria.

Systematic characterization of sperm-specific membrane proteins in swine

To establish a systematic strategy for characterizing fertilization proteins of sperm cells, we prepared alloantisera by immunizing gilts with salt-washed membranes from boar spermatozoa. The antisera recognized a unique subset of sperm membrane proteins that migrated with M(r) 7500-66,000 in SDS-PAGE under nonreducing conditions. The antisera did not recognize proteins of erythrocyte membranes, and tissue absorption experiments further confirmed that the alloantigens were sperm-specific proteins. Each of these sperm-specific membrane proteins (SSMPs) possessed one or more disulfide bonds that were essential for its interaction with alloantibody. Enzymatic deglycosylation revealed that most of the SSMPs were glycoproteins, and their alloantigenicity was not dependent on the presence of N-linked oligosaccharides. The presence of disulfide bonds and glycosylation indicated that the SSMPs identified each comprise at least one extracellular domain. Two-dimensional electrophoresis resolved at least 14 distinct SSMPs, 13 of which possessed acidic pIs (range 4.2-4.8). By indirect immunofluorescence, the SSMPs localized to the cell surface overlying all major regions of the sperm cell. We conclude that the repertoire of immunodominant SSMPs in the pig is relatively small, which makes feasible the systematic elucidation of their functions in fertilization.

A histologic study of the auto-allergic testis lesion in the guinea pig

The auto-allergic lesion in guinea pigs inoculated with homologous testis plus the Freund adjuvant was investigated histologically. The lesion was found to consist of disseminated foci of perivenous inflammation, lymphocytes and histiocytes predominating in the cellular infiltrate, with invasion of epididymal, rete, and seminiferous tubules and destruction of tubular contents. Guinea pigs up to 800 gm. showed a rapidly progressing diffuse hypo- or aspermatogenesis, which appeared to be secondary to the inflammatory disease. In these animals, the process resolved leaving an atrophic testis with few or no indications of the preceding inflammation and fibrotic scarring only in the rare instances in which actual necrosis of connective tissue elements had occurred. In 1200 gm. animals there was no general hypospermatogenesis and the late findings were limited to foci of aspermatogenesis. This disease then is an experimental auto-allergic orchitis followed by testicular atrophy without scarring. Its morphologic similarity to mumps orchitis and to sterility with "germinal cell aplasia" in man is commented on.

The relationship of delayed hypersensitivity and circulating antibody to experimental allergic thyroditis in inbred guinea pigs

Strain 13 histocompatible guinea pigs developed allergic thyroiditis after immunization with thyroid extracts derived from the same strain or from other strains of guinea pigs. This thyroiditis appeared as early as 5 days after immunization, and by 7 weeks was uniformly present and generally severe. 7 weeks after immunization, the anti-thyroid antibody titer correlated with the presence and degree of thyroiditis. However, at certain other times after immunization, the titer did not correlate with the thyroiditis. By contrast, all animals with thyroiditis, which were skin-tested with thyroid extract, exhibited delayed hypersensitivity. Moreover, all those which failed to respond with delayed reactions, when skin-tested, had not developed thyroiditis. The present work correlates the presence of experimental allergic thyroiditis with delayed hypersensitivity.

Suppression of allergic encephalomyelitis in rats by means of antibrain serum

Rats regularly develop evidence of allergic encephalomyelitis (AE) 2 to 3 weeks following sensitization to nervous tissue plus adjuvant. Independent of the severity of AE which occurs, gradual recovery is the rule and by the 6th to 9th week after sensitization rats appear clinically well and microscopic lesions of AE have virtually disappeared. Pooled serum collected from rats 3 or 6 weeks after sensitization contains complement-fixing (CF) antibrain antibodies. Such pooled serum exerts a striking suppressive influence on development of AE when passively administered to rats actively sensitized to nervous tissue. Serum pools which contain CF antibrain antibody suppress the disease. Serum pools lacking CF antibody do not suppress the disease. Serum containing CF antibrain antibody after treatment with 2-mercaptoethanol no longer fixes complement with brain antigen in vitro and no longer suppresses AE in vivo. The data suggest that transfer of protection against AE by passively administered antibrain rat serum is due to an antibrain antibody, possibly the CF antibodies. The meaning of these findings is discussed in terms of the role(s) of circulating antibrain antibody in the pathogenesis of AE.

Transfer of an autoimmune nephrosis in the rat by means of lymph node cells

An autoimmune nephrosis produced in rats by repeated injections of kidney extract with Freund's adjuvant has been transferred by means of lymph node cells to recipient animals rendered tolerant by neonatal injection with spleen cells from prospective donors. Transfer of the disease was manifested in the recipients by the development of proteinuria, hypoalbuminemia, hypercholesterolemia,and histological changes. The latter consisted of glomerular epithelial swelling, increase in basement membrane material and the presence of protein droplets in the glomerular and tubular epithelium. Appropriate control experiments were negative. Attempts to transfer with serum were unsuccessful. The transfer described is believed to provide evidence for an immunological mechanism for kidney and adjuvant induced nephrosis in the rat.

Immunological adjuvance of metabolic origin: oxidative stress, postulated impaired function of thiol proteases and immunogenicity

Autoimmune disease may sometimes arise because of dysfunction of thiol proteases, which are vulnerable to oxidation of their sulphydryl groups. This may be initially signalled by hyperinsulinaemia, regarded here as a telltale phenomenon of oxidative stress and indicating difficulty in protein catabolism. Initial immunogenic sensitization may take place when antigen processing is altered by a metabolic process, which has locally overwhelmed the antioxidant systems and led to diminished thiol-protease digestion and to the repeated survival in critical cells of immunogenic peptide fragments. From this it follows that an immunological host may be either prejudiced towards or against tolerance by agents, respectively, which stabilize or destabilize antioxidant homeostasis.

Destruction of epidermal cells in vitro by autologous serum from normal animals

Sera and plasma from normal rats and rabbits were shown to be extremely toxic in vitro to autologous epidermal cells. On the other hand, mouse sera and newborn rat sera were innocuous to autologous epidermal cells. Viability of cells was assessed by the method of eosin dye exclusion upon 2 hour incubation at 37 degrees C. Testicular cells were also killed by autologous sera, but polymorphonuclear leukocytes, lymphocytes, and lymph node cells were not affected. Autotoxicity of sera could be destroyed by the depletion of complement components with an antigen-antibody precipitate, heat, zymosan, and NH(3). Moreover, activity of sera could be absorbed out by epidermal cells, though not by lymph node cells or erythrocytes. Such absorption of toxicity was not individual-specific since homologous epidermal cells also absorbed toxicity, and in addition, were killed by fresh normal serum. Enzyme inhibitors such as soybean trypsin inhibitor and epsilon-amino-n-caproic acid did not affect the activity of fresh autologous serum. It is suggested that a natural barrier exists between the basal cells of the epidermis and the plasma which prevents the autodestructive process under normal conditions. Any injury to this barrier may than lead to necrosis and death of the epidermis as seen in various pathological conditions.

THE COURSE OF EXPERIMENTAL AUTOALLERGIC THYROIDITIS IN INBRED GUINEA PIGS. THE PATHOLOGIC CHANGES AND THEIR RELATIONSHIP TO THE IMMUNE RESPONSE OVER A 2 YEAR PERIOD

Experimental allergic thyroiditis produced in strain 13 histocompatible guinea pigs after a single immunization with thyroid extract and Freund's adjuvant was followed for more than 2 years. The disease appeared as early as 5 days and persisted for the entire period studied, although it regressed in the later stages. Circulating antithyroid antibody was detected at low levels as early as 7 days after immunization, and increased to a peak at the time of most severe disease. Thereafter, antibody decreased, but was still detectable in most animals as late as 2 years. There was no correlation between antibody levels and extent of disease except at the 7 week stage. Delayed sensitivity to thyroid antigen was found as early as 5 days after immunization, and appeared to precede the development of thyroiditis in many animals. It correlated closely with thyroiditis at 5 days and 7 weeks. At 6 months, the delayed skin reaction was decreased, and a modified type of reaction appeared which persisted as long as 26 months. The time relationship of delayed sensitivity, thyroiditis, and circulating antibody continue to confirm the role of delayed sensitivity in the pathogenesis of this disease. The accumulated data demonstrating production of thyroiditis without antibody, and the converse, tend to strengthen this view.

Immunology of the testicular excurrent ducts

The sperm autoantigen concentration in the epididymis equals or exceeds that in the testis. This makes the epididymis a probable site of initiation of an antisperm autoimmune response. The mechanisms regulating antisperm antibody formation in the testicular excurrent ducts and some related aspects with clinical interest are reviewed.

The cognitive paradigm and the immunological homunculus

In last month's issue of Immunology Today, Irun Cohen discussed the inadequacies of the clonal selection paradigm and proposed a cognitive paradigm in which preformed internal images guide and restrict the process of clonal activation. Here he clarifies the nature of these internal images, during on concrete examples from the image of infection and the image of self, the immunological homunculus.

Human autoantibody to Sertoli cells detected in healthy individuals

Human autoantibody to Sertoli cells was detected in normal human sera. This IgM-type autoantibody was undetectable during the neonatal period and was found in 11.5% of 365 serum samples taken from adult healthy persons of both sexes. This human autoantibody to Sertoli cells exhibited quite the same target-organ specificity and multi-organ reactivity (salivary gland ductules, pancreatic intercalated duct, renal lower nephron, pituitary acidophilic cells) as those of the murine monoclonal autoantibody (IgM class) to Sertoli cells (TM-1: WHO registered code T43). The TM-1 monoclonal antibody could recognize testicular antigens with molecular weights of 67,000 and 23,000 in Sertoli cells, and had already been demonstrated capable of inducing murine experimental spermatogenic disturbance when administrated together with murine monoclonal autoantibody to seminiferous tubular basement membrane (TM-2: WHO registered code T44). These observations may suggest that human spermatogenic disturbance could be easily induced by the multi-organ reactive autoantibody to Sertoli cells even in healthy individuals under particular conditions where this autoantibody can be allowed to reach the target Sertoli cells across the barrier of seminiferous tubular wall by either autoantibody to seminiferous tubular basement membrane or other toxic damage.

A new mouse model for autoimmune orchitis

Experimental autoimmune orchitis (EAO) was induced in SMA mice (H-2nondefined) by repeated injection at intervals of 30 days of syngeneic testis homogenate (TH) together with Klebsiella O3 lipopolysaccharide (KO3 LPS) as a potent adjuvant. EAO was not induced by repeated injection of TH alone or KO3 LPS alone. At 10 days after the secondary injection of TH + KO3 LPS, there was marked infiltration with neutrophils in the seminiferous tubules and in the interstitium of the testis accompanied by destruction of the architecture of the seminiferous tubules and hypospermatogenesis. At 20 days after the secondary injection, infiltration with neutrophils in these areas had been replaced mostly by mononuclear cells (lymphocytes, plasma cells, and macrophages). Histopathological changes of the testes became severer by further injections until the 10th injection. The EAO lesions in the terminal stage were characterized by complete destruction of the tubular architecture of the testis, fibrosis, and aspermatogenesis. Lesions in the terminal stage were not restored at all. Spermagglutinating antibody titers in the serum increased and delayed-type hypersensitivity against TH estimated by footpad swelling developed in mice injected repeatedly with TH + KO3 LPS. Using immunofluorescence, antibodies against acrosomal components and tail components of the spermatozoa were detected in serum of these mice.

Association of antisperm antibodies with chronic nonbacterial prostatitis

Antisperm antibodies are significant in male factor infertility. The prevalence of antisperm antibodies in the infertile population is approximately 10 percent, and it is not cost-effective to test for these antibodies in every male partner of an infertile marriage. Earlier studies have demonstrated a higher prevalence of antisperm antibodies among men with a history of bacterial prostatitis or urethritis. Because of this established association, we measured the prevalence of serum antisperm antibodies, using a gel agglutination assay, in 28 men with chronic nonbacterial prostatitis and in age-matched control group of 69 men without a history of prostatitis. The prevalence was 25 percent (test subjects) and 7.2 percent (controls) (p less than 0.05). This finding indicates that nonbacterial prostatitis is a risk factor for the presence of serum antisperm antibodies and that subfertile men with a history of nonbacterial prostatitis should be tested for these antibodies.

Activation of the immune system in the testis

The present concept for the mechanism of prolonged transplant survival in the testis suggests that lymphocyte activation is inhibited locally in this site by testicular products. As the testis produces several immunoregulatory factors, the behaviour of lymphocytes in the testis may depend on the net effect of all these factors on intralymphocytic events. In the present article, the extra- and intracellular events associated with lymphocyte activation are reviewed and the steps of lymphocyte activation which might be subject to interference by testicular factors are identified.

Presence and distribution of leucocyte subsets in the murine epididymis after vasectomy

Male mice were vasectomized by 'open-ended' or 'closed' techniques. After 4 weeks the cell-mediated immune reactions were compared with those of sham-operated animals by immunohistochemical localization of leucocytes, using specific monoclonal antibodies. Macrophages and MHC class II antigen-positive cells were the major cell types to appear in all regions of the epididymis after both types of operation. There was recruitment of T-helper/inducer leucocytes but not of T-suppressor-cytotoxic cells. An increased presentation of macrophage-migration inhibiting factor antigen appeared in interstitial and peritubular locations. After 'closed' and 'open-ended' vasectomy granulomata developed in the epididymis. The sperm-containing lumen of these granulomata was invaded by macrophages, MHC class II-positive cells and T-helper/inducer lymphocytes. This mouse model thus reveals a significant epididymal inflammatory response of the epididymis to vasectomy.

Adoptive transfer of murine autoimmune orchitis with sperm-specific T lymphoblasts

A protocol was successfully developed for reproducibly transferring experimental autoimmune orchitis (EAO) to naive recipient mice with sperm-specific T lymphoblasts. Cell donors were Balb/c mice immunized about 12 days earlier with homologous epididymal sperm capacitated in vitro with complete Freund's adjuvant. Draining lymph node cells were collected and subjected to a second challenge with the same sperm antigen in vitro. Sperm-specific T lymphoblasts were isolated on Percoll density gradients and propagated in the presence of interleukin-2 for 3 days and then were transferred intraperitoneally to naive recipients. As few as 3 x 10(6) sperm-specific T lymphoblasts were able to transfer EAO, which began on day 7 as infiltration of lymphocytes and macrophages and on days 14 to 21 developed to degenerative changes of spermatids and exfoliation of germinal epithelium. These pathologic alterations resemble a delayed type of hypersensitivity. The results show that sensitized T lymphoblasts can mediate an antigen-specific, mononuclear cell-invasive lesion in autoimmune orchitis.

Sequential study of the histopathology and cellular and humoral immune response during the development of an autoimmune orchitis in Wistar rats

Wistar rats immunized with an homologous testicular homogenate (TH) and complete Freund's adjuvant, followed by i.v. injection of Bordetella pertussis, developed an autoimmune orchitis (EAO). Animals were studied at 7, 16, 30, 50, and 80 days (d) after the first immunization. An important lesion of the testis only appeared at 50 d, increasing in severity and incidence (77%) at 80 d. Lesions were characterized by a prevalent aspermatogenesis with tubular atrophy and mild interstitial mononuclear infiltrates. Delayed-type hypersensitivity response (DTH) against TH was detected early at 7 d and, except for 16 d, it increased with time, reaching a maximum at 80 d. A good temporal relationship between DTH and histopathology was found. Circulating antibodies to TH, detected by ELISA, were only present in 64% of the animals with testis lesion, while no deposits of IgG or C3 in the seminiferous tubules were seen. We describe a sequence of immunological events, concomitant with pathological changes of the testis, during the development of a severe EAO in Wistar rats.

Spontaneous immune complex orchitis in brown Norway rats

Immune complexes occur spontaneously in the testis of Brown-Norway (BN) inbred rats between the basal lamina of the seminiferous tubules and the outer lamina of the myoid testicular cells. The deposits can be detected immunohistologically (IgG; C3) and by electron microscopy. The immune complexes appear between the 8th and 12th weeks of life, increase in amount up to the 30th week and decrease thereafter. After about the 20th week, of life, 15% of the animals show destruction of the germinal epithelium accompanied by an infiltration of lymphocytes and plasma cells. The final stage of this disease, which initially shows no signs of inflammation, is characterized by diffuse tubular atrophy. However, up to the 70th week of life, 85% of the animals with immune complexes show no pathological alterations. Antibodies eluated from the testes react with spermatocytes I and structures close to the lumen of the seminiferous tubules, but not with mature sperms. Serum antibodies to sperms occur in about 25% of the BN rats, but the presence of these antibodies shows no correlation with the immunohistological findings. This newly described spontaneous immune complex orchitis is regarded as a further example of an in-situ-induced immune complex disease. The observations made here can be compared with those in (peri-) membraneous glomerulonephritis, another example of a disorder resulting from in-situ-formation of immune deposits.

The effect of unilateral experimental testicular torsion on spermatogenesis and fertility

Significant subfertility exists in patients following unilateral testicular torsion, implying bilateral testicular disease. Immunological activation has been detected after experimental torsion and the present study sought to demonstrate immunologically mediated effects on contralateral spermatogenesis following experimental torsion, as well as quantifying ipsilateral damage. Early and late effects of torsion on bilateral spermatogenesis were studied at 1 and 6 months in 10 groups each containing 20 rats. Gross and histological examination, direct immunofluorescence tests, vas deferens counts and copulation studies were performed. Severe ipsilateral damage was noted, even after brief torsion periods. No contralateral testicular effects, immunological or otherwise, were observed. Ipsilateral damage after torsion may have been underestimated. There is no damage to contralateral testicular exocrine function following unilateral experimental torsion.

Morphologic effects of unilateral cryptorchidism on the contralateral descended testis

Unilateral cryptorchidism is frequently accompanied by infertility. Uncertainty exists as to whether the infertility is a genetic effect or is related to an autoimmune reaction to the elevated testis. The effects of unilateral cryptorchidism were evaluated in 50 mice by surgically elevating the left testicle of 21-day-old mice into the abdomen (AT). A sham operation was performed on the left testicle of 50 control mice (SHT). The temperature of the abdominal testes measured 2.5 degrees C higher than the scrotal testes. The testes were removed from both sides at 1, 2, 3, 4 and 6 weeks postoperation. After testicular weights were recorded, seminiferous tubule diameters were measured, and germinal epithelium maturity was graded histologically using a modified Johnson testicular biopsy score. Progressive abnormal changes were seen in the contralateral descended testicles of AT as compared to SHT. By 3 weeks, though testicular weight changes were similar, mean seminiferous tubule diameter was smaller (P less than .001), and the germinal epithelium was less mature (P less than .001). These changes persisted through the sixth week. By changing the physiologic environment of one testicle, we have induced alterations in the histologic appearance of the contralateral testicle during the period of normal maturation.