Vasectomy: consequences of autoimmunity to sperm antigens

Possible biological mechanisms for a relationship between vasectomy and prostatic cancer

Four hypotheses have been reviewed, each of which might serve as a hypothetical biological explanation for a relationship between vasectomy and prostate cancer. The endocrine hypothesis is the only one of these with any firm data to support it, although the majority of the available data does not lend credibility to that theory. The other hypotheses are purely speculative with no hard data to support them. In conclusion, it seems highly unlikely, but not impossible, that there is a biological mechanism supporting a relationship between vasectomy and prostate cancer.

Ultrastructure of epididymal interstitial reactions following vasectomy and vasovasostomy

The response of the male reproductive tract to vasectomy includes inflammation of the interstitial tissue of the epididymis. The pathogenesis of epididymal interstitial reactions and characteristics of the responding cells were studied by electron microscopy in Lewis rats at intervals following bilateral vasectomy, vasectomy followed 1 month later by vasovasostomy, or sham operations. In areas of interstitial reaction, numerous macrophages, monocytes, lymphocytes, neutrophils, and plasma cells occupied the connective tissue. Macrophages, containing many lysosomes and vesicles, aggregated and assumed the appearance of epithelioid cells. Processes of adjacent macrophages interdigitated with one another and closely approached the surfaces of lymphocytes. Many plasma cells with distended rough endoplasmic reticulum appeared in the interstitium. The majority of animals in the vasectomy and vasovasostomy groups exhibited epididymal interstitial changes by 2-3 months; the cauda epididymidis was the region most often affected. The ultrastructural features were indicative of chronic granulomatous inflammation and were consistent with an immune response that includes antigen presentation by macrophages to lymphocytes, lymphocyte differentiation, and local antibody production by plasma cells. The nearly complete absence of sperm or recognizable parts thereof in the interstitial tissue in the areas of the reactions suggests that these lesions formed in response to soluble antigens leaking from the duct. Vasovasostomy was not effective in reversing or retarding epididymal inflammation at the intervals studied.

Localization of post-vasectomy sperm autoantigens in the Lewis rat

Major rat sperm autoantigens of 86, 63, 43, 28 and 20 kDa are recognized by post-vasectomy and hyperimmunization antisera from the Lewis rat (Handley et al., Biol. Reprod. 39 (1988) 1239-1250). In the present study, affinity purified monospecific isoantibodies to each autoantigen were produced by elution from antigens which had been separated by SDS-PAGE and transferred to nitrocellulose. Western blot analysis confirmed a singular specificity for the 63, 28 and 20 kDa antisera and demonstrated some cross reactivity between the 86 kDa and the 43 kDa antisera. The polyclonal antiserum from which the monospecific antisera were produced stained the entire spermatozoon, while monospecific antibodies bound only to the sperm tail, staining the proximal portion (43 and 28 kDa), a distal domain (63 kDa), or the entire tail (86 kDa). Immunohistochemically stained sections of normal rat testes revealed that the 63, 43 and 28 kDa autoantigens were synchronously expressed in the cytoplasm of spermatids in the apical portions of seminiferous tubules during stages II-VIII in the cycle of the seminiferous epithelium. The 86 kDa autoantigen showed little or no staining in testis sections, implying that this autoantigen appeared on mature sperm following spermiation. These and other data suggest that a highly polymeric structure, possibly within the outer dense fibers of the tail, is a dominant sperm autoimmunogen following vasectomy of the Lewis rat.

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.

The humoral autoimmune response to vasectomy described by immunoblotting from two-dimensional gels and demonstration of a human spermatozoal antigen immunochemically crossreactive with the D2 adhesion molecule

The specificity of human serum antispermatozoal antibodies was analysed by immunoblotting after two-dimensional electrophoretic separation (IEF/PAGE) of human spermatozoal proteins. Spermatozoal proteins with Mr 20-200 kDa and pI between 4.5 and 7.8 were analysed for antigenicity. Fifteen sera (four female and 11 male) were analysed for antisperm IgG antibodies. Individual IgG binding patterns were observed. The antisperm antibody response to ligation of the vas deferens was described by immunoblotting analysis of sera taken pre- and post-operatively at regular intervals from three men undergoing vasectomy. The high resolution of spermatozoal antigens allowed a specific description of the humoral response to vasectomy. Both appearance and disappearance of spots were observed in the postoperative period, indicating induction of new antibody producing clones and binding of former free antibodies in circulating immunocomplexes. In one patient five glycosylated proteins induced an IgM response 2 weeks after vasectomy. Four of these autoantigens with Mr of 122 kDa, 119 kDa, 104 kDa and 77 kDa and pI of 5.9, 6.1, 7.7 and 6.0, respectively, have previously been shown to be intrinsic membrane proteins (Naaby-Hansen, (1990) J., Reprod. Immunol. 17). An observed immunochemical crossreactivity between the interneuronal adhesion molecule, D2-protein and an antigen extracted from human sperm and teratomas is discussed.

Low incidence of sperm antibodies in men with congenital absence of the vas deferens

The incidence of antisperm antibodies in serum and seminal fluid of 27 azoospermic men with congenital absence of the vas deferens is evaluated. The presence of antisperm antibodies was assessed using the immunobead test, the agglutination test, and immobilization test. Five patients with vasovasostomy or vasoepididymostomy attempts were included in the study and tested for the presence of antisperm antibodies. Contrary to a previous report, a low incidence (11%) of antisperm antibodies has been found in patients with congenital absence of the vas. In agreement with previous studies, in five patients who had failed vasoepididymostomy or vasovasostomy, a high incidence (71%) of antisperm antibodies was found.

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.

Testicular atrophy in homosexual AIDS patients: an immune-mediated phenomenon?

An immunopathologic analysis of the testes of 20 homosexual acquired immune deficiency syndrome (AIDS) patients was performed to investigate the hypothesis that the testicular atrophy of these patients represents an immune-mediated process. The findings were compared to those in a control group of heterosexual men without AIDS. The testes of the homosexual AIDS patients showed an overall lower degree of spermatogenesis with more prominent interstitial inflammation and thickening of the tubular basement membrane. However, direct immunofluorescence and immunoperoxidase studies failed to demonstrate significant differences in the prevalence of immune complex deposits along the tubular basement membrane in the two study groups. No electron-dense deposits were demonstrated in cases examined ultrastructurally. Therefore, this study does not support the hypothesis that the testicular atrophy of homosexual AIDS patients is a manifestation of autoimmune orchitis. Further studies are needed to elucidate the pathogenesis of the testicular atrophy in AIDS, as this appears to be a specific manifestation of the disease.

Atherosclerosis of cynomolgus monkeys hyper- and hyporesponsive to dietary cholesterol. Lack of effect of vasectomy

A moderately atherogenic diet was fed to young adult cynomolgus macaque males that were observed to be either hypo- or hyperresponsive to dietary cholesterol and who were randomized into groups to be either vasectomized or sham-vasectomized. The extent of atherosclerosis was found to be considerably greater at all arterial sites studied for the monkeys that were hyperresponsive to dietary cholesterol. The differences in atherosclerosis development among the hyperresponder monkeys occurred primarily in the proximal portions of the coronary arteries, the proximal and distal portions of the common carotid arteries, and only in the most proximal portions of the femoral arteries. There were no significant effects of vasectomy or sham vasectomy on atherosclerosis extent in either the hyper- or the hyporesponding groups, although there was a suggestion of somewhat larger lesions in the left circumflex coronary artery of hyperresponder monkeys that were vasectomized and somewhat smaller atherosclerotic lesions in the left common carotid arteries of vasectomized monkeys. The data presented here do not support our first report of worsened atherosclerosis among cynomolgus monkeys fed diets high in cholesterol. The findings of the current study are consistent with recent epidemiological studies of vasectomized and nonvasectomized human males.

Testicular alterations are linked to the presence of elevated antisperm antibodies in Sprague-Dawley rats after vasectomy and vasovasostomy

The relationship between alterations in testicular histology and antisperm antibodies was studied after vasectomy and vasovasostomy in Sprague-Dawley rats, which are immunologically relatively non-responsive to vasectomy. Testes were prepared for histologic study at intervals up to seven months after vasectomy, vasectomy followed three months later by vasovasostomy, or sham operations. Antisperm antibodies were assessed with an ELISA. Testicular alterations, which were observed in a minority of animals after vasovasostomy, consisted mainly of depletion of germ cells. Mean serum antisperm antibody levels were greater for animals with altered testes than for rats with normal testicular histology. In addition, the proportion of rats that showed a positive antisperm antibody response was greater among animals with testicular changes than among those with unaltered testes. When the present results on Sprague-Dawley rats were compared with previous findings on the highly responsive Lewis strain, it was evident that the incidence of testicular changes and the proportion of positive antibody responders were greater in the Lewis strain. However, elevated antisperm antibodies and testicular alterations appeared to be more tightly linked in the less responsive Sprague-Dawley rats.

Vasectomy-induced autoimmunity: monoclonal antibodies affect sperm function and in vitro fertilization

A panel of sperm-reacted monoclonal auto-antibodies developed from spleen cells of vasectomized mice (BDF1) were characterized. Immunogenic antigens were mainly located on the acrosome, midpiece and principal piece. All of the monoclonals were IgM; three demonstrated a multispecific reaction with testis and/or epididymis antigen extracts by immunoblotting. Immunobead studies indicated that most of the antibodies were to surface molecules, a finding supported by the observation that five of the seven antibodies caused complement-mediated immobilization (although not sperm agglutination) of mouse sperm. In vitro fertilization was significantly impaired when antibodies (Vx5, 8 and 10) were added to the sperm prior to exposure to the eggs. Furthermore, passive immunization with Vx5 antibody reduced in vivo fertilization. Our findings indicate that vasectomy-generated antibodies can reduce sperm function in vitro and in vivo.

Detection of the major epitopes of human protamine P1 recognized by rabbit and mouse antibodies

The characterization of the major antigenic determinants present in human protamine P1 has been carried out by the use of specific rabbit polyclonal and mouse monoclonal antisera raised against protamine P1. This basic protein, the full amino acid sequence of which has been determined here, has been cleaved by cyanogen bromide and/or by pepsin to generate a discrete number of peptides. These have been purified, characterized by partial amino acid sequencing and used for the determination of their antigenic reactivities with antisera to native protamine P1. Both rabbit polyclonal and mouse monoclonal antibodies were able to recognize the NH2-terminal CNBr peptide encompassing residues 1-36 to the same extent as the intact protamine. A minor epitope present on the COOH-terminal peptide 37-50 could be detected only with the polyclonal rabbit antisera. Attempts to further cleave the P1 molecule in order to isolate peptides shorter than fragments 1-36 whilst retaining full antigenic reactivities, were unsuccessful. This suggests that the epitopes in P1 are conformation-dependent and located for the most part on the amino-terminal half of the molecule, which comprises the characteristic central arginine cluster. The implication of these findings for the studies of the specificities of autoantibodies in sera from infertile and vasectomized individuals is discussed.

Effect of vasectomy on humoral and cell-mediated immunity in monkeys with experimentally induced atherosclerosis

The development of humoral and cell-mediated immune responses and circulating immune complexes following vasectomy were studied in rhesus monkeys fed a high cholesterol (atherogenic) diet. Four groups of monkeys were studied: (i) sham-vasectomized males fed a normal stock diet, (ii) sham-vasectomized males fed an atherogenic diet, (iii) vasectomized males fed a normal stock diet, and (iv) vasectomized males fed an atherogenic diet. Monkeys were observed for a period of 1.5 years. Sperm agglutinins and immobilizins in serum were detected in 100 and 60%, respectively, of vasectomized monkeys fed stock diet. In contrast, 60% of vasectomized monkeys fed an atherogenic diet showed agglutinins in their sera and only 20% exhibited immobilizins. The sensitization of lymphocytes by seminal plasma antigens was of a lower order in vasectomized monkeys fed an atherogenic diet as compared to those maintained on a stock diet. Circulating immune complexes (CIC) were present in both the groups of vasectomized monkeys but the level was higher in animals fed an atherogenic diet. The aortic atherosclerosis score was increased significantly in vasectomized monkeys fed an atherogenic diet, whereas the coronary atherosclerosis score was increased both in vasectomized males and in animals fed an atherogenic diet.

Immunohistochemical characterization of seminoma and its inflammatory cell infiltrate

Monoclonal antibodies and the avidin-biotin immunoperoxidase technique were used to study the expression of major histocompatibility complex antigens and the nature of the inflammatory cell infiltrate in 10 testicular seminomas. Tumor cells did not react with anti-HLA-A,B,C, anti-HLA-DR, anti-HLA-DQ, and anti-beta 2 microglobulin antibodies to major histocompatibility antigens. All of the 10 tumors contained a slight to marked inflammatory cell infiltrate at the periphery of the tumor, in the connective tissue septa, and in the tumor lobules. The lymphocytes were predominantly T cells; B lymphocytes were rare. The tissue available for study from seven tumors showed tumor lobules separated by delicate fibrovascular septa; T lymphocytes with a cytotoxic-suppressor phenotype predominated in this area in six tumors. In the four tumors in which peripheral tissue was available for study, cells with a helper-inducer phenotype predominated at the tumor margin. Tissue from three tumors showed stromal sclerosis and a dense lymphohistiocytic infiltrate separating individual and small nests of tumor cells; T cells with a helper-inducer phenotype predominated in these cases. Aggregates of macrophages that expressed OKM-1 and Leu-M3 were present in eight of 10 tumors. These findings indicate that two types of immune reactions may be operating: a delayed-type hypersensitivity response at the periphery and a cytotoxic-suppressor effector mechanism in the tumor lobules. Furthermore, major histocompatibility complex antigens are not involved in eliciting the inflammatory response.

In vitro immune absorption of antisperm antibodies with immunobead-rise, immunomagnetic, and immunocolumn separation techniques

Fourteen men with a mean duration of infertility greater than 3 years who had significant sperm immobilizing or sperm-agglutinating antibodies were studied. All patients had greater than 20% IgG or IgA immunobinding to sperm in their seminal plasma and 7 had immunobinding levels of greater than 50%. Sperm from these men were less able to penetrate an overlaying buffer layer than sperm from a fertile control. Addition of immunobeads to the specimen was of little use, because few motile sperm could swim into the overlaying buffer; retained immunobeads were noted in the buffer layer of 18-hour capacitated specimens. Magnetic isolation of antibody-coated sperm from antibody-free sperm avoids potential damage to fragile sperm through centrifugation. Viable spermatozoa were isolated from magnetite-complexed spermatozoa, but the motility of the isolated spermatozoa deteriorated rapidly during the subsequent capacitation period. Passage of diluted ejaculate through a column of dextran beads for antisperm antibody processing (ASAP) was associated with superior sperm quality and fertilizing potential. The use of ASAP resulted in good sperm velocity and linearity and improved sperm function, as measured with the hamster egg penetration test. Sperm from men with immunologically mediated infertility can be processed through the ASAP and used for artificial insemination of their partners or in an in vitro fertilization program.

Qualitative differences in sperm antibody responses in mice of different inbred strains and sexes

To better understand the immunogenetic basis and potential pathological consequences of anti-sperm humoral immunity, age-matched female mice of 9 different inbred strains were immunized with syngeneic sperm and were tested for qualitative (specificity) and quantitative (titer) antibody differences by radioimmunoassay, immunofluorescence and immunoblot techniques. All mice developed antisperm antibodies, although titers varied considerably between inbred strains. Antisperm antibodies produced in this study did not cross-react with membrane antigens on thymocytes, brain or immature testicular germ cells. Immunoblot tests identified 17 major sperm antigen bands; this approach also revealed considerable inter- and intra-strain variation in antisperm antibody specificities among female mice. In a parallel study C57BL/6 male mice demonstrated significantly lower antisperm antibody titers and an absence of response to certain sperm antigens in immunoblot tests when compared to age-matched females of the same inbred strain. These findings provide evidence that genetic factors (including sex) interact with environmental (nongenetic) factors in the control of immune responses to sperm antigens.

The incidence of spermatic granulomas and their relation to testis weight after vasectomy and vasovasostomy in Lewis rats

The occurrence of spermatic granulomas of the vas deferens was studied in Lewis rats at intervals up to 7 months after vasectomy or vasectomy followed 3 months later by vasovasostomy. The incidence of granuloma progressed with time to involve one or both tracts in 100% of vasectomized rats. In addition, the majority of animals developed new granulomas after vasovasostomy, even though fluid flow through the reconnected vas deferens was demonstrated in vitro. When individual tracts were analyzed, the weight of the testis was related to ipsilateral spermatic granuloma formation in both vasectomy and vasovasostomy groups at 3 and 4 months after initial operation. Testes were small in the absence of a granuloma but similar to those of sham-operated rats if a granuloma was present. The possible protective effect of spermatic granuloma formation on the testis is discussed.

Diet and vasectomy: effects on atherogenesis in cynomolgus macaques

We report here the effect of a moderately atherogenic diet on the progression of atherosclerosis among cynomolgus macaques that were either vasectomized or sham vasectomized. Both groups were compared to sham vasectomized monkeys fed a control Monkey Chow diet. As expected, slight hyperlipoproteinemia induced by the moderately atherogenic diet increased endothelial cell replication rates and resulted in the development of intimal lesions among sham vasectomized monkeys. Unexpectedly, vasectomy resulted in reduced leukocyte adherence to arterial surfaces, reduced endothelial cell replication rates in response to the moderately atherogenic diet, and at most arterial sites, smaller intimal lesions were produced. These data suggest that with slight hyperlipoproteinemia vasectomy may result in a small protective effect against atherosclerosis, while other studies have shown that marked hyperlipoproteinemia in cynomolgus macaques along with vasectomy results in exacerbation of atherogenesis.

Serum lipid levels before and after vasectomy in men

The blood lipid profile was determined in sixty-two men, 24 to 62 years old, before and two, six and twelve months after surgical occlusion of the vas deferens. No statistically significant differences were found in mean body weight, blood pressure, serum levels of non-esterified fatty acids, total lipids, triglycerides, total cholesterol and alpha, beta and prebeta fractions of the lipoproteins, which were measured before and after surgery. When the serum levels of the alpha and beta fractions were considered in the same subject, it was observed that 12 months after vasectomy a similar percentage of cases showed a predominance of either one of them. Hence, no modifications on the lipid profile of these subjects were found that could indicate an increased risk of arteriosclerotic disease.

Effect of vasectomy on high density lipoproteins

Primate research has associated vasectomy with accelerated rates of atherogenesis. We have evaluated the effect of vasectomy on serum lipoprotein profiles in healthy men. There was a decrease in high density lipoprotein levels, which was greatest in men with a family history of atherosclerotic disease. With the great number of variables known to affect high density lipoprotein levels further studies are needed to determine if this change can be attributed to the vasectomy.

Vasectomy-induced autoimmunity: antisperm and antinuclear autoimmune monoclonal antibodies

Antibodies to sperm and testicular autoantigens are a hallmark of vasectomy-induced murine autoimmunity. We generated five autoimmune monoclonal antibodies with spleen cells from nonimmunized but vasectomized BDF1 male mice as fusion partners in two experiments. Four of the antibodies, designated Vx 4, Vx 8, Vx 10, and Vx 23, recognize, as determined by fluorescence microscopy, topographically restricted sperm-specific antigenic determinants that appear in the germinal epithelium as spermatogenesis progresses. Antibodies Vx 8 and Vx 10 identified 60,000- and 97,000- dalton, mouse-specific sperm antigens restricted to the anterior acrosome and posterior acrosome, respectively. Antibody Vx 23 identified a 35,000- to 40,000- dalton antigen on the midpiece and postacrosomal regions of epididymal mouse sperm. The antigenic target of antibody Vx 4 on the midpiece region could not be identified with the Western blot technique. Both Vx 4 and Vx 23 cross-reacted with human, rabbit, and monkey sperm; immunofluorescence revealed that they were bound onto the midpiece region. By immunofluorescence, a single clone (Vx 24) distinctly reacted with the nuclei of somatic and testicular germ cells but not the nuclei of sperm. The isolation of this antinuclear autoantibody raises questions about the development of nonsperm-specific autoantibodies after vasectomy in the mouse.

Long-term effect of vasectomy on coronary heart disease

We investigated the association between coronary heart disease (CHD) and vasectomy in a population of 10,632 men who were under surveillance for multiple CHD risk factors during participation in a university-based exercise testing program. We conducted a mail survey with telephone follow-up to determine the vasectomy status of individuals in the population. Responses were obtained from 6,159 individuals. The 4.944 males on whom information was complete enough to be included in the multivariate analysis comprised the study population. Among the 1,383 (28 per cent) vasectomized males in the study populations, the interval from vasectomy to the time of the survey ranged from less than one year to 37 years with a mean duration of 15 years. Although increased relative risks for CHD were found to be associated with family history of CHD, high blood pressure and smoking in this population, the relative risk of CHD associated with vasectomy was not increased in general, nor was it increased when the vasectomized males were classified by time since vasectomy. Likewise, serum antisperm-antibody titers were not predictive of CHD among vasectomized men. These studies support the findings from previous investigations of populations with shorter average post-vasectomy experience in which vasectomy has been shown to be unassociated with altered risk of CHD in humans.

Vasectomy and nonfatal myocardial infarction: continued observation indicates no elevation of risk

The incidence of nonfatal myocardial infarction among 4,733 vasectomized men followed for 33,969 man-years was 1.3 cases per 1,000 man-years. This incidence was nearly identical in a 5-fold larger series of comparable nonvasectomized men. These data represent a substantially increased long-term followup over that reported previously for these groups and provide continued assurance of the lack of an association between vasectomy and myocardial infarction, particularly 10 or more years after vasectomy.

The significance of antinuclear antibodies in juvenile rheumatoid arthritis associated with chronic bilateral iridocyclitis

Serum samples from 8 children with juvenile rheumatoid arthritis (JRA) and chronic bilateral iridocyclitis were significantly distinguished from 5 children with JRA and no eye symptoms by the presence of large immune complexes (IC) greater than 22S, IgM antinuclear antibodies (ANA), IgG granulocyte-specific (GS-) ANA, C3 fixing ANA, and IgM anti-IgG. One serum with and two sera without IC greater than 22S, all from patients with iridocyclitis, were fractionated by rate zonal ultracentrifugation. Each fraction relevant for the study was separately concentrated and reexamined. In one of the sera without IC greater than 22S this technique exposed the presence of IgA GS-ANA not detectable in the corresponding whole serum. IgG ANA were precipitated in an area with higher molecular weight than the one for IgG indicating the presence of aggregated IgG ANA. Fractionation of the serum with IC greater than 22S demonstrated IgM GS-ANA not present in whole serum. The results support previous suggestions that ANA may be involved in the pathogenesis of chronic iridocyclitis and may explain why ANA (in particular C3 fixing ANA) negative patients with JRA rarely develop chronic iridocyclitis.

Sperm-agglutinating and -immobilizing antibody formation following vasectomy prevented with dexamethasone in cynomolgus monkeys

Cynomolgus monkeys (Macaca fascicularis) were treated with 1.5 mg/kg dexamethasone (DEX) before (4 to 2 days) and after (0, 2, 4, and 7 days) vasectomy. Of the four monkeys treated with DEX, only one developed sperm antibody as measured by sperm-agglutinating and sperm-immobilizing assays. All six of the vasectomized monkeys not given DEX developed both agglutinating and immobilizing sperm antibodies. In this study, DEX given before and after vasectomy blocked sperm-agglutinating and -immobilizing antibody formation. We conclude that the major antigenic exposure to sperm responsible for sperm-agglutinating and -immobilizing antibody comes at the time of vasectomy.

Sperm antibodies in serum and semen in men with bilateral congenital absence of the vas deferens

Sperm antibodies were evaluated in serum and semen of 14 cases with bilateral congenital absence of the vas deferens, by agglutination and complement dependent tests. The level of the various immunoglobulin fractions were determined by the single radial immuno diffusion method. Sperm agglutinins were present in serum in 71% of cases and in 29% in semen. Immunoglobin (Ig) M was not detected in semen of both patient and control groups, while IgG and IgA were absent in the semen of patients.

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

Spleen cells from mice injected intravenously with syngeneic male germ cells exhibited reduced immune functions as determined by natural killer cell activity, mixed lymphocyte reactivity and cytotoxic lymphocyte (CTL) function. The decrease in CTL responses to trinitrophenyl-modified self (TNP-self) was detected as early as 4 d after sperm injection and was observed to H-2 alloantigens 3 wk after injection. Radiosensitive suppressor T cells were found to suppress the CTL response to TNP-self. Suppression lasted for a period of at least 7 wk after a single inoculation of the germ cells. Some variability in immune suppression capability was observed using different preparations of germ cells which are not yet completely understood. Sperm were more effective in inducing suppression than testicular cells derived from the seminiferous tubules. Furthermore, sperm from older animals were more effective than those from younger mice. These findings are discussed with respect to possible regulatory influences of germ cells on the immune system when the blood-testes barrier is broken.

Humoral sperm antibodies: a 10-year follow-up of vas-ligated men

Fourteen men were studied over a period of 10 years before and after bilateral was ligation. Seven men (50%) continued to have demonstrable circulating sperm-agglutinating antibodies, and one man had persistent sperm-immobilizing antibodies at a low titer of 1:2. None of the 10 ejaculates submitted contained spermatozoa or antibody activity, although two of the seminal plasma specimens immediately immobilized donor spermatozoa upon contact. There were no adverse medical reactions or conditions noted in these men during the course of the study.

Vasectomy and non-fatal myocardial infarction

The incidence of non-fatal myocardial infarction among 4830 vasectomised men was 0.9 cases per 1000 man-years during 24 420 man-years of observation. This was slightly lower than the rate in 24 150 non-vasectomised men, matched with a vasectomised man for calendar year of birth and duration of observation. Review of medical records for a matched sample of study subjects indicated no measurable confounding by important cardiac risk factors.

Immunologic infertility: identification of patients with antisperm antibody

Immunologic causes of infertility have been postulated for many years, but a precise means for identification of men or women with antibodies against sperm has not been available. We studied 614 patients, including 257 couples, with unexplained in fertility, to detect the presence of circulating antisperm antibody. Using a specific radiolabeled-antiglobulin test, we identified a subset of patients (10 per cent) with IgG antisperm antibody; this antibody was present in 13 per cent of the women and 7 per cent of the men. We followed the course of six infertile couples in whom one partner had sperm antibody. In four couples, pregnancy was achieved; pregnancy correlated with resolution of antibody activity. In two of these four couples the partner (one man and one woman) with antisperm activity had been pretreated with corticosteroids. We conclude that this objective test may be used to identify and then to help manage infertility in patients with suspected antibody-mediated infertility.