Antibodies to the neutral glycolipid asialo ganglio-N-tetraosylceramide: association with gynecologic cancers

As part of our efforts to define subpopulations at increased risk for gynecologic malignancies, sera from 145 women were obtained prior to diagnosis and analyzed for antibody to asialo ganglio-N-tetraosylceramide. This neutral glycolipid is present on the surface of thymocytes and natural killer cells, and asialo ganglio-N-tetraosylceramide antibody has been shown in animals to block natural killer cell activity and promote tumor cell proliferation. With the use of an enzyme-linked immunosorbent assay and with a value of 2 SD above the mean for healthy women designated as the boundary for a positive response, antibody to asialo ganglio-N-tetraosylceramide was detected in only one of 30 (3%) healthy women, none of 16 pregnant women, none of 18 women with benign masses, and two of 24 (8%) women with microbial infections. All of the above samples that contained antibodies were barely over the 2 SD limit. In marked contrast, 19 of 35 (54%) women with gynecologic malignancies had asialo ganglio-N-tetraosylceramide antibodies, with positive values ranging to greater than 10 SD above the control mean. Asialo ganglio-N-tetraosylceramide antibody was found in six of eight (75%) patients with cervical cancer, five of eight (63%) with endometrial cancer, and seven of 15 (47%) with ovarian cancer. Of the eight patients with Stage I gynecologic cancer at any site, five (62%) had asialo ganglio-N-tetraosylceramide antibodies. Four of 22 (18%) women with Hodgkin's disease also had antibodies, with values just exceeding 2 SD above control levels. The presence of these antibodies may contribute to an impaired immune surveillance system in these women and so increase their susceptibility to malignancy.

Non-immune IgG binding to the surface of spermatozoa by disulphide rearrangement

The mechanism whereby immunoglobulin binds to the surface of spermatozoa was investigated. IgG reacts with spermatozoa non-specifically via the Fc portion of the molecule, while both IgM and IgA are completely unreactive. This selective binding of IgG is non-competitive, resistant to heat, proteases and non-ionic detergents and is not mediated by an Fc receptor on the sperm surface. Instead, evidence is presented that IgG covalently binds to spermatozoa by an exchange reaction between labile disulphides on both the sperm surface and IgG-Fc. It is calculated that there are 3 X 10(11) exchangeable disulphide bonds per bull spermatozoon.

Circulating immune complexes in sera of patients with gynecologic disorders

Sera from 211 women seen in the Department of Obstetrics and Gynecology at the New York Hospital were assayed for CIC by the Raji cell enzyme linked immunosorbent assay. Only 9 per cent of healthy women (two of 21), 6 per cent of pregnant women (two of 34), 2 per cent of women with benign tumors (one of 39) and 5 per cent of women with vaginal and cervical infection (two of 37) had detectable CIC. CIC was present in low concentrations when it was found. In marked contrast, 80 per cent of the patients with Condylomata acuminatum infection (eight of ten), 46 per cent with acute salpingitis (11 of 24) and 39 per cent with gynecologic malignant diseases (13 of 33) had CIC, usually at high levels. In a patient with salpingitis, CIC was shown to be 19S and 14S, dissociable at acid pH and capable of activating complement.

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

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

Analysis of sera from ovarian cancer patients for immune complexes

In contrast to other malignancies, circulating immune complexes (CICS) are usually not detected by conventional assays in the sera of ovarian cancer patients. However, a polyethylene glycol (PEG) precipitation assay has been reported to detect putative CICS in ovarian cancer. To determine if CICS were indeed present, we analyzed sera from 12 women with ovarian cancer. All were negative for CICS by the Raji cell assay; 5 (42%) were positive by the PEG assay. However, the PEG precipitate did not possess characteristics of immune complexes. IgG in sera or in the precipitate sedimented in sucrose gradients solely at the same rate as 7S monomeric IgG. In addition, the precipitates were not able to activate the complement system and the four IgG subclasses were present in the same relative concentration as that found in normal serum. The results suggest that it is probably a misnomer to label the material detected in ovarian cancer sera by the PEG precipitation assay as CICS. Instead a non-immune interaction of IgG with other components, possibly membrane fragments, is probably being measured.

Circulating immune complexes and sperm antibodies following vasectomy in Austrian men

The incidence of circulating immune complexes (CICs) following vasectomy in men and the timing of their appearance and disappearance remain unsettled. A prospective study was initiated to measure CICs and sperm antibody formation in 44 Austrian men undergoing a vasectomy. Using the Raji cell assay, the incidence of CICs was 11% (5 of 44) prior to surgery, 24% (10 of 42) at 2-3 months, 10% (1 of 10) at 4-6 months and 0% (0 of 23) at 15-26 months following surgery. The incidence of sperm antibodies, employing a sperm agglutination assay and an enzyme-linked immunosorbent assay, was 7% (3 of 44), 17% (9 of 52), 25% (3 of 12) and 27% (3 of 11), at 0, 2-6, 15-20 and 21-26 months following vasectomy, respectively. CICs and sperm antibody levels were not correlated at any time point. These results support previous studies indicating a transient increase in the incidence of CICs, detectable by the Raji cell assay, only at early times following vasectomy.

Rectal insemination modifies immune responses in rabbits

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

Inhibition of Candida albicans--induced lymphocyte proliferation by lymphocytes and sera from women with recurrent vaginitis

To investigate whether there was an immunologic basis for recurrent Candida albicans-induced vaginitis, peripheral blood lymphocytes were isolated from six women with this disorder and from six healthy control women. No differences were observed in the proliferative responses of peripheral blood lymphocytes to mitogens. However, only the control peripheral blood lymphocytes proliferated in response to a C. albicans extract. Furthermore, patients' lymphocytes or serum suppressed the proliferative response of control lymphocytes to C. albicans but not to mitogens. Women with recurrent C. albicans vaginitis appear to produce Candida-specific suppressor lymphocytes which block the cellular immune response to this organism.

Relationship between genital tract infections, sperm antibodies in seminal fluid, and infertility

To explore possible relationships between genital tract infections, sperm antibodies, and infertility, seminal fluid from 100 men was analyzed. Sperm antibodies, measured by an enzyme-linked immunosorbent assay, were detected in 14 of 29 men (48%) with culture-positive asymptomatic infections, 8 of 17 men (47%) with a history of prostatitis or urethritis, 11 of 33 men (33%) with either a varicocele or an abnormal semen analysis, and only 1 of 21 men (5%) with no infection and a normal semen analysis. The incidence of sperm antibodies in the men with infections or urethritis or prostatitis was significantly higher than in the control subjects (P less than 0.005). The sperm antibody isotype in men with infections was mainly IgA, although IgG or IgM were also sometimes present. Of the men with asymptomatic infections, urethritis or prostatitis, significantly (P less than 0.025) more men without sperm antibodies (12 of 24, 50%) were fertile than were those with sperm antibodies (3 of 22, 13%). Men with genital tract infections have a high incidence of antibodies, reactive with spermatozoa, which is associated with reduced fertility.

Influence of complement depletion on sperm function in the female rabbit

Female rabbits were wholly depleted of complement by treatment with anti-complementary cobra venom factor (CVF) 36 h before mating. Complement depletion did not compromise occurrence of the acrosome reaction, as judged by sperm penetration of eggs collected 12-13 h post coitum. However, in CVF-treated females, significantly more spermatozoa had penetrated the egg vestments, more spermatozoa were present in flushings from the oviducts, and sometimes the uterus, than in control females mated to the same males. The results indicate that, although the acrosome reaction is unlikely to depend on complement activation, complement-dependent factors may exert a restrictive effect on spermatozoa after vaginal insemination of the normal female rabbit.

Influence of epididymal maturation on the capacity of hamster and rabbit spermatozoa for complement activation

Hamster and rabbit spermatozoa released from the epididymis were tested for the ability to activate complement via the alternative pathway. While hamster spermatozoa were more active, the spermatozoa of both species reduced complement activity in homologous and also human serum previously adsorbed to remove sperm antibodies, and they bound C3 in the presence of EGTA + Mg2+. Hamster spermatozoa from the caput epididymidis were more anticomplementary and bound more C3 than did cauda spermatozoa and, though less marked, a similar difference was evident between caput and cauda spermatozoa from the rabbit epididymis.

Induction of antibody to asialo GM1 by spermatozoa and its occurrence in the sera of homosexual men with the acquired immune deficiency syndrome (AIDS)

Compared to healthy homosexual and heterosexual men, homosexual men with acquired immune deficiency syndrome (AIDS) possessed significantly higher levels of IgG antibody to the neutral glycolipid asialo GM1 (ganglio-N-tetraosylceramide) (P less than 0.01). Of 31 homosexuals with AIDS, 36% possessed levels of this antibody that were at least two standard deviations above the mean of the healthy men. Furthermore, asialo GM1 antibody could be removed from serum by adsorption with spermatozoa. Weekly rectal insemination of male rabbits with rabbit semen also led to the appearance of antibody to asialo GM1 by 15 weeks. These results suggest that asialo GM1 is a component of ejaculated spermatozoa and demonstrate that rectal insemination by itself can lead to the production of antibodies to this glycolipid in the rabbit. In addition, asialo GM1 antibodies may be of value as a serological marker for the early detection of individuals with AIDS.

Characterization of a human anti-hCG antiserum: a proposed standard for laboratories involved with the development of hCG vaccines

An antiserum (PC-81-1) was obtained from a man who developed antibodies against hCG during treatment for hypogonadism. The antiserum was unique in that its affinity for hCG was high (greater than 10(-10) M(-1] and its cross-reaction with hLH and the hCG-subunits was only 1-12.5% and 0.01%, respectively, of intact hCG. We propose that this human antiserum be used as a laboratory standard by investigators who are developing vaccines directed against hCG. The use of this standard in the proposed protocol will permit comparison of titers between laboratories. Lyophilized samples of antiserum PC-81-1 are available on request from the Population Council.

Acquired immunodeficiency syndrome, opportunistic infections, and malignancies in male homosexuals. A hypothesis of etiologic factors in pathogenesis

The acquired immunodeficiency syndrome (AIDS) occurs in a subgroup of male homosexuals having sexual contact with a large number of partners. Uncommonly, AIDS has also been diagnosed in Haitians, hemophiliacs, and intravenous drug users and their infants. Manifestations include autoimmune disturbances, opportunistic infections, Kaposi's sarcoma, chronic lymphadenomegaly, non-Hodgkin's lymphoma, or squamous cell carcinoma. The hypothesis receiving most consideration is that a yet-to-be-identified virus causes AIDS. An alternative view is that repeated sexual involvement with multiple partners, in a subgroup of male homosexuals, exposes the men to the immunosuppressive impact of cytomegalovirus (CMV) and allogeneic semen. Antibody to asialo-Gm1 and other antigens on sperm react with and impair lymphoid cells. We propose a biphasic process. First, a reversible acquisition phase of impaired T-cell immunoregulation permits reactivation of Epstein-Barr virus (EBV), and autoantibodies are produced by the activated B cells. If sexual activity continues at a high level, accumulating immune defects, including destruction of thymic epithelium, lead to a second, self-sustaining phase wherein cytotoxic lymphocytes fail to eliminate herpesvirus-infected cells. Evidence is mounting that Kaposi's sarcoma is caused by CMV and that EBV is responsible for the B-cell lymphomas in these patients. Multiple factors, rather than a novel virus, probably induce AIDS in male homosexuals. If this hypothesis is correct, then rational bases for prevention and intervention can be designed.

Comparison of different assays for circulating immune complexes in age matched vasectomized and non-vasectomized men

Sera from 46 men vasectomized for 5 yr and from 46 age-matched nonvasectomized men had previously been analyzed for circulating immune complexes (CICs) by four assays. Four additional CIC assays have now been performed on these sera: three Raji cell enzyme-linked immunosorbent assays (ELISAs) using alkaline phosphatase-conjugated antihuman IgG, IgA or C3 and the bull sperm ELISA. No significant differences in CIC levels were detected between the two groups using any of the assays. Results for two different sera obtained from 16 men 4 1/2 months apart correlated significantly for six of seven CIC assays evaluated in this way. In the bull sperm and Raji cell ELISAs, utilizing anti-IgG in the detection layer, the vasectomized men with sperm-agglutinating antibodies were found to have significantly higher CIC levels than those without sperm agglutinants. No association was found between the presence of sperm protamine antibody and levels of CICs. Since the vasectomized and control groups did not differ with respect to levels of CICs, immunoglobulins, or the complement C3 split product C3d, all 92 samples were combined into one group for further analysis. Serum IgG levels significantly correlated with the CIC levels in four of five CIC assays involving binding of IgG; IgA levels correlated with CIC determinations in the Raji-IgA assay, while plasma C3d levels correlated with the Raji-C3, the Raji-IgA, and the C1q-protein A binding assays. IgM levels did not correlate with activity in any assay. Finally, the degree of correlation between all eight CIC assays was determined, and significant positive correlations between assays were found in ten of twenty-eight comparisons.

Immune responses to spermatozoa in homosexual men

Immunologic responses to spermatozoa were investigated in homosexual and heterosexual men. Ten of 18 (56%) of the homosexual men had serum levels of IgG antibody to spermatozoa that were at least 2 standard deviations above the mean level for the heterosexual men; only 2 homosexual men had IgA antibody to spermatozoa. Similar increases above heterosexual levels in sperm-related antigen were detected in the sera of 56% (10 of 18) of the homosexual men. Circulating immune complexes (CICs) were detected at high levels (greater than 1000 micrograms/ml) in 61% (11 of 18) of the homosexual men. The CICs were relatively small (less than 14S), as determined by sucrose gradient analysis. Only 3 of 18 (17%) of the heterosexual men had CICs, and these were at a much lower concentration (less than or equal to 700 micrograms/ml). In the homosexual men, CICs and sperm-related antigen levels were positively correlated (r = 0.41, P less than 0.001), while IgG sperm antibody levels were negatively correlated with both CIC levels (r = -0.24, P less than 0.01) and sperm-related antigen levels (r = -0.24, P less than 0.01). CICs from six homosexual men were analyzed for composition. All contained IgG, and two had evidence of sperm-related antigen. The results suggest that intake of spermatozoa via the alimentary canal may lead to the development of a humoral immune response to spermatozoa.

Effects of long-term immunization against the beta-subunit of ovine luteinizing hormone on circulating immune complex formation and on arterial changes in rhesus monkeys

A major safety issue of contraceptive methods based on long-term immunization is the possible effect of circulating immune complexes (CIC) on the arterial wall. We have measured CIC's in 24 monkeys, immunized against the beta-subunit of ovine luteinizing hormone (oLH beta), emulsified with Freund's complete adjuvant, and in 7 nonimmunized controls by Raji assay, Clq assay, and an assay for rheumatoid factor. Eleven of the 24 immunized monkeys had CIC concentrations that were more than two standard deviations above the mean for controls in at least one of the assays. There was no correlation between antibody titer and CIC. Nine immunized and eight control animals on low-fat diets were killed to evaluate the effects of immunization on the artery wall. The cross-sectional intimal area was measured at several sites from projected microscopic images using a sonic digitizer. No statistically significant differences between test and control groups were found. However, when we compared the upper half of the distribution of test and control animals, we found that the mean intimal area of the thoracic aorta of immunized monkeys was twice that of controls and that that of the abdominal aorta was three times as large. These data indicate that long-term immunization against oLH beta induced CIC's in rhesus monkeys. Small increases in the intimal area were found in about half of the immunized animals. The results of this study suggest the need for a larger, more definitive study in which the diet is manipulated so that plasma lipids mimic those of human females in Western society.

HUMORAL IMMUNE RESPONSES IN HEALTHY HETEROSEXUAL, HOMOSEXUAL AND VASECTOMIZED MEN AND IN HOMOSEXUAL MEN WITH THE ACQUIRED IMMUNE DEFICIENCY SYNDROME

In homosexual men, the acquired immune deficiency syndrome (AIDS) is associated with sexual promiscuity and the appearance of circulating immune complexes (CICs) and antibodies to spermatozoa which crossreact with lymphoid cells. A comparative study was initiated to determine whether similar humoral responses existed in 38 heterosexual men lacking sperm antibodies, 13 heterosexuals with sperm antibodies, 42 heterosexual vasectomized men, 22 healthy homosexual men, 26 homosexuals with lymphadenopathy and 16 with AIDS or Kaposi's sarcoma (KS). Sperm antibodies were detected in 12% of the vasectomized heterosexual men, 23% of the healthy homosexuals, 35% of the lymphadenopathy patients and 44% of the men with KS-AIDS. IgG reactive with peripheral blood T lymphocytes was present in only 3% of heterosexuals lacking sperm antibody and 5% of vasectomized men. In contrast, 23% of heterosexuals with sperm antibody, 36% of healthy homosexuals, 31% of men with lymphadenopathy and 62% of KS-AIDS patients were positive in this assay. Antibodies to the neutral glycolipid asialo GM1 were found in none of the vasectomized men, 3% of the heterosexuals without and 8% with sperm antibodies, 17% of healthy homosexuals and 38% and 31% in patients with lymphadenopathy or KS-AIDS, respectively. Lastly, the incidence of CICs, determined by the Raji cell assay, was 0% in vasectomized men, 3% in heterosexuals lacking sperm antibody, 31% in heterosexuals with sperm antibody, 69% in healthy homosexuals, 81% in lymphadenopathy patients and 87% in KS-AIDS. In the homosexuals with lymphadenopathy and KS-AIDS, levels of CICs, T cell-reactive IgG and asialo GM1 antibody were positively correlated (p less than 0.01). Sperm antibody levels were negatively correlated (p less than 0.01) with CICs levels and T cell reactive IgG in heterosexuals and lymphadenopathy and KS-AIDS patients. The results demonstrate that vasectomized men do not manifest at all, and that non-vasectomized heterosexuals with sperm antibodies manifest to a much lesser extent the range of humoral immune responses exhibited by the three homosexual groups. Thus, the route of sperm immunization and/or exposure to autologous vs. heterologous spermatozoa may be of critical importance for eliciting specific immune responses.

An IgG-Fc binding protein in seminal fluid

Human seminal fluid, at low dilutions, prevented the binding of aggregated human IgG (AHG) to bull spermatozoa. Seminal fluids from vasectomized men were also inhibitory. Preincubation of the seminal fluid with the spermatozoa prior to washing and addition to AHG had no inhibitory effect, indicating that the fluid component was reacting directly with AHG. Human seminal fluid was fractionated by gel exclusion chromatography on Ultrogel AcA-34, and AHG inhibitory activity was found in fractions corresponding to a molecular weight of 94,000. The activity in this fraction was stable to boiling for 10 min. It was sensitive to pronase but resistant to glycosidase, phospholipase C, neuraminidase, ribonuclease, and deoxyribonuclease, indicating that it was a protein. The gel filtration fraction readily bound recrystallized Fc and AHG; IgG was bound to a lesser extent, and no reactivity was observed with F(ab')2, IgA, or IgM. Thus, the seminal fluid fraction appeared to specifically react with the Fc portion of IgG. The seminal fluid Fc-binding protein was isolated by affinity chromatography on Fc coupled to CNBr-activated Sepharose 4B. Scatchard analysis revealed that the binding of the seminal fluid Fc-binding protein to recrystallized Fc is reversible and had a Kd of approximately 3 x 10(-6) M.

Suppressor T lymphocytes and cross-reactive sperm antigens in human semen

Studies were initiated to further explore possible interrelationships between semen and the immune system. Ejaculates from healthy donors were found to contain an average of 2.6 X 10(6) mononuclear cells and 0.8 X 10(6) lymphocytes. These seminal lymphocytes exhibited suppressor activity when co-cultured with autologous peripheral blood lymphocytes. Reactivity of monoclonal antibodies to all human T lymphocytes (OKT3) and to T suppressor/cytotoxic lymphocytes (OKT8) with purified T lymphocytes was shown by enzyme-linked immunosorbent assay (ELISA) to be reduced by 70-90% following pre-incubation of the antibodies with ejaculated human spermatozoa. Reactivity of mononuclear antibody to T helper/inducer lymphocytes (OKT4) with T lymphocytes was unaffected by spermatozoa. Since T suppressor lymphocytes present in sperm-containing fractions could be responsible for any reactivity of OKT3 and OKT8 antibodies with spermatozoa, lymphocyte-free sperm preparations were prepared. OKT3 and OKT8, but not OKT4, were shown by ELISA to react with purified human spermatozoa. Shared antigenic determinants between lymphoid cells and spermatozoa and/or the occurrence of lymphocytes in semen may, in some situations, induce alteration in immune functions following exposure to semen.

Sperm-related antigens, antibodies, and circulating immune complexes in sera of recently vasectomized men

Sera from 35 men were collected before and at timed intervals subsequent to vasectomy and examined for the presence of (a) antibody reactive with human spermatozoa, (b) sperm-related antigen, and (c) circulating immune complexes (CIC). Fewer than 10% of the men examined were ever positive for antisperm antibodies. However, sperm-related antigens were elevated in the sera of 18, 18, and 26% of the mean at 2 wk, 2 mo, and 4 mo postvasectomy, respectively. CIC were detected in the sera of some vasectomized men by three different assays. The CIC in patients' sera were precipitated with polyethylene glycol, dissociated, and the individual CIC components identified by an enzyme-linked immunosorbent assay. Most, but not all, of the CIC contained antigen reactive with antisperm immunoglobulin (Ig)G and some also contained complement components C3 and/or Clq. IgA was identified in some of the CIC positive for IgG and sperm antigen and two men had IgM-containing CIC. Analysis of the CIC by sucrose gradient centrifugation revealed them to be heterogeneous in size.

IgA antibody to spermatozoa in seminal and prostatic fluids of a subfertile man

the mechanism of spontaneous sperm agglutination in the ejaculate of a subfertile man was investigated. Using enzyme-linked immunosorbent assays it was found that the patient's spermatozoa had a mean of 2.3 times more IgA bound to it than did spermatozoa from fertile men. IgA antibody to spermatozoa was also found in the patient's seminal fluid and prostatic fluid, but not in his serum. In this patient it appeared that agglutination was due to an IgA antibody to spermatozoa that was produced locally within the genital tract.

Antibody-independent complement activation by myelin via the classical complement pathway

Murine or rabbit whole brain homogenates were shown to activate human complement via the classical pathway by an antibody-independent reaction. This activity required Ca++ ions. Anticomplementary activity in fractionated murine brain was found to reside in the myelin fraction and in purified myelin. It was absent, however, both from highly purified myelin basic protein (MBP) and from the MBP-free residue. Because purified MBP is a monomer and this protein exists in brain tissue largely as a dimer, the ability of the cross-linked form of MBP to activate complement was investigated. MBP, dimerized with difluorodinitrobenzene, was highly anticomplementary. The murine brain, inactive when taken from the newborn mouse, was shown to first acquire the capacity to activate complement at 7 d after birth. This finding is consistent with the report that the synthesis of myelin protein has been shown to be initiated in murine brain 8 d after birth. Complement activation by MBP could play an important role in the pathological changes observed in neurological disorders.

Demonstration of 11S IgA antibody to spermatozoa in human seminal fluid

Spontaneous sperm agglutination was observed in the ejaculate of a 39-year-old male (patient Z). Using an enzyme-linked immunosorbent assay (ELISA) with spermatozoa fixed to wells of a microtitre plate it was determined that IgA was associated with patient Z's spermatozoa but not with a pooled sample of spermatozoa from fertile men Z's seminal fluid agglutinated human spermatozoa (titre 1:16). In contrast, no sperm-agglutinating or immobilizing activity was present in the patient's serum. Agglutination was prevented by preincubation of the seminal fluid with anti-IgA antibody but not with anti-IgA antibody. IgG from Z's seminal fluid readily bound to human spermatozoa, as determined by the ELISA assay. IgA from a pool of seminal fluids from fertile men or from 18 human sera bound to spermatozoa to a much lesser extent. By sucrose-gradient velocity centrifugation it was demonstrated that the anti-sperm IgA in patient Z's seminal fluid was 11S. Finally, antibody to secretory component removed the anti-sperm IgA from Z's seminal fluid. These data provide evidence that secretory IgA with anti-sperm activity is produced in the male genital tract. Furthermore, a new methodology is presented for the determination of antibodies to spermatozoa.

Antibodies reactive with murine mammary tumor virus in sera of patients with breast cancer: geographic and family studies

Sera of patients with breast cancer, of healthy women from the United States, East India, East Africa, and China, and of healthy women of American and Parsi families in which breast cancer occurred in several family members were assayed for levels of antibody reactive with the murine mammary tumor virus (MuMTV) by an enzyme-linked immunosorbent assay. Increased levels of antibody to MuMTV (absorbance greater than or equal to 0.4) were found in sera of 18.6% of American patients with breast cancer and of 2.8% of healthy American women and in 38% of patients from India and 61.9% from East Africa (healthy, 26.9%). In contrast, antibody reactive with MuMTV was found in less than 5 of women with breast cancer from mainland China (healthy Chinese, 5.0%). Differences in serum MuMTV antibody levels between breast cancer patients in the four groups were found to be significant (P less than 0.0001). Studies of two families from the United States and of one Parsi family from India with genetic propensity to breast cancer showed that high levels of antibody to MuMTV were found in 33%, 71%, and 23% of healthy family members, respectively. The antibody to MuMTV was readily absorbed with purified MuMTV and gp52. In contrast, fetal calf serum, murine type c retroviruses, or erythrocytes from various species failed to absorb the antibody.

Antigens and antibodies cross-reactive to the murine mammary tumor virus in human breast cyst fluids

Human breast cyst fluids were shown to contain low concentrations of IgA (15-78 micrograms/ml) and IgG (33-145 micrograms/ml). The IgA:IgG ratios in individual breast cyst fluids ranged from 1:0.6 to 1:4. These levels are considerably higher than their ratio in serum (1:7). IgA from 33% of the 40 fluids examined, and IgG from 10% of the fluids, reacted with the murine mammary tumor virus (MuMTV). The reactivity was detected by an enzyme-linked immunosorbent assay that measures antibody binding to both the envelope glycoprotein and core protein of the virus. In a second series of experiments. IgA from 28% of 40 breast cyst fluids reacted only with MuMTV while IgA from 30% of the fluids was reactive with both MuMTV and the Rauscher murine leukemia virus. Antigen reactive with antiserum to the 28,000-dalton MuMTV core protein (p28), was also identified in a 165,000-g pellet fraction from breast cyst fluids. In individual fluids, the extent of IgA binding to MuMTV was positively correlated (P less than or equal to 0.01) with the binding of anti-p28 antibody to the pellet of the breast cyst fluid. Fractions with the buoyant density of retroviruses (1.16-1.18 g/ml) or their cores (1.21-1.25 g/ml) were isolated from breast cyst fluids. These fractions contained a DNA polymerase capable of utilizing the reverse transcriptase-specific template, dG12-18 x poly rCm. In addition, they reacted with antiserum to MuMTV p 28 but not with antiserum to the 30,000-dalton Rauscher murine leukemia virus core protein.

The effect of diet on autogenous immunity to mouse mammary tumor virus in C3H/Bi mice

Antibody levels to mouse mammary tumor virus (MuMTV) in sera of C3H/Bi, C57BL/6 and AKR mice were assayed by an enzyme-linked immunosorbent assay (ELISA). It was found that antibody levels to MuMTV were highest in sera of C3H/Bi females which have a high incidence of breast cancer and low in male C3H/Bi and female C3H/Bi foster-nursed on C57BL/6 females. Sera of C57BL/6 and AKR mice showed very low or undetectable levels of antibody to MuMTV. Reduction of caloric intake sufficient to inhibit mammary tumor formation strikingly inhibited formation of antibody against MuMTV. The lowest levels of antibody were observed in sera of mice fed 10 cal/day of a defined diet. Significantly higher levels developed in the sera of mice fed 16 cal/day of the same defined diet. The highest antibody levels against MuMTV, however, were seen in sera of mice fed lab chow ad libitum but no correlation was evident between levels of antibody and tumor size. These studies indicate that dietary caloric restriction has a profound influence on the development of both mammary adenocarcinoma and antibody responses to MuMTV.

Circulating immune complexes associated with naturally occurring lymphosarcoma in pet cats

Cats were classified into 4 categories by immunofluorescence antibody assay for the presence of feline leukemia virus (FeLV) and histologically as a) normal, FeLV-, b) normal, FeLV+, c) lymphosarcoma (LSA), FeLV+, and d) LSA, FeLV-. Determinations by Raji cell radioimmunoassay modified for cat serum revealed circulating immune complex (CIC) levels of healthy cats to be less than or equal to 50 micrograms equivalent aggregated cat immunoglobulin/ml (microgram/ml). In contrast, sera of cats in groups b, c, and d all contained significantly higher CIC levels (up to 12,000 micrograms/ml) associated with marked hypocomplementemia and C activation occurring via the classical pathway. Sera from FeLV+, LSA+ cats with high levels of CIC and sera of healthy cats were fractionated according to size and bouyant density by centrifugation through 10 to 40% sucrose gradients. Analysis of fractions from LSA+, FeLV+ sera revealed that both immune complexes (ICs), FeLV reverse transcriptase (RT), and IgG were present in fractions corresponding to a bouyant density of 1.15 to 1.18 g/ml. The CIC containing fractions activated C by the classical pathway. Sera from normal cats did not have CIC or RT and none of the fractions activated the classical pathway. These data suggest that vital antigen-antibody complexes are present in sera of viremic cats with LSA and these complexes activate the C system.

Circulating immune complexes associated with naturally occurring lymphosarcoma in pet cats

Cats were classified into 4 categories by immunofluorescence antibody assay for the presence of feline leukemia virus (FeLV) and histologically as a) normal, FeLV-, b) normal, FeLV+, c) lymphosarcoma (LSA), FeLV+, and d) LSA, FeLV-. Determinations by Raji cell radioimmunoassay modified for cat serum revealed circulating immune complex (CIC) levels of healthy cats to be less than or equal to 50 micrograms equivalent aggregated cat immunoglobulin/ml (microgram/ml). In contrast, sera of cats in groups b, c, and d all contained significantly higher CIC levels (up to 12,000 micrograms/ml) associated with marked hypocomplementemia and C activation occurring via the classical pathway. Sera from FeLV+, LSA+ cats with high levels of CIC and sera of healthy cats were fractionated according to size and bouyant density by centrifugation through 10 to 40% sucrose gradients. Analysis of fractions from LSA+, FeLV+ sera revealed that both immune complexes (ICs), FeLV reverse transcriptase (RT), and IgG were present in fractions corresponding to a bouyant density of 1.15 to 1.18 g/ml. The CIC containing fractions activated C by the classical pathway. Sera from normal cats did not have CIC or RT and none of the fractions activated the classical pathway. These data suggest that vital antigen-antibody complexes are present in sera of viremic cats with LSA and these complexes activate the C system.

Demonstration of IgG Fc receptors on spermatozoa and their utilization for the detection of circulating immune complexes in human serum

The presence of Fc receptors, but not C3 receptors, on human and bovine spermatozoa was shown by sperm-induced rosette formation of antibody-treated ox erythrocytes and by immunofluorescence of aggregated human gammaglobulin (AHG) treated spermatozoa. Human and bovine spermatozoa bound AHG as well as circulating immune complexes (CIC) from human sera; monomeric IgG bound to these cells to a much lesser extent. Binding of AHG to the sperm surface also occurred when the AHG was suspended in either buffer or in serum that had been heated at 56 degrees C for 30 min. A bovine spermatozoa radioimmunoassay for the detection of immune complexes in human sera was developed and was shown to be comparable to the Raji cell radioimmunoassay (r = 0 . 81, P < 0 . 01) in the quantitation of soluble immune complexes from a variety of human sera. An enzyme-linked immunoassay was then developed, using bovine spermatozoa fixed to wells of microtitre plates, to simplify the immune complex detection assay. The technique provides an analysis that is rapid, does not require radioactive chemicals, expensive equipment, or cultured cells and yields values for immune complex determination both comparable and complementary to the Raji cell radioimmunoassay (r = 0 . 70, P < 0 . 01). The sperm assays detected soluble immune complexes in sera of vasectomized males, cancer patients and patients with autoimmune or dermatological diseases.

Properties of a DNA polymerase from purified nuclei and DNA-synthesizing complexes of human spermatozoa

A DNA polymerase was isolated from human spermatozoa. In one procedure, spermatozoa were decapitated with detergent, the heads purified and then lysed with dithiothreitol, trypsin and deoxyribonuclease. DNA polymerase was isolated from the lysate by sedimentation through an 18% Metrizamide solution, solubilization with 0.8 M-KCl-0.5% Triton X-100 and sequential chromatography on DEAE cellulose, phosphocellulose and hydroxylapatite. Alternatively, the heads of intact spermatozoa, untreated with detergent, were lysed as above; the subsequent Metrizamide pellet fraction was isolated and further fractionated by gel filtration and buoyant density centrifugation. The enzyme in this fraction was solubilized with KCl-Triton X-100. Characterization by velocity centrifugation and phosphocellulose chromatography revealed that it possessed properties indistinguishable from those of the enzyme purified from isolated sperm nuclei. The DNA polymerase had an apparent molecular weight of 79,000-89,000, Mn2+ (1 mM) was the preferred divalent cation and ativity was inhibited by concentrations of potassium phosphate greater than 10 mM. The synthetic template preferences of the enzyme were dT12-18 . poly rA > poly(dA-dT) > dT12-18 . poly dA; no activity was observed with dG12-18 . poly rC or dT10.

In vitro activation of feline complement by feline leukemia virus

Incubation of normal feline serum with purified feline leukemia virus (FeLV) at 37 degrees C for 30 min resulted in the activation of the complement system via the classical pathway as demonstrated by consumption of the C1, C4, C2, C3, and, to a lesser extent, the later C components. A similar finding was observed when normal human serum was substituted for normal cat serum. In contrast, complement-dependent lysis of FeLV with normal feline serum as assayed by the release of ribonucleic acid-dependent deoxyribonucleic acid polymerase was one-third that of complement-dependent FeLV lysis with normal human serum. The levels of total hemolytic complement and neutralizing antibody in individual feline sera were also not proportional to the degree of virolytic activity. These observations indicate that the inefficient virolysis of FeLV by normal cat serum may be one of the factors contributing to the high incidence of leukemia observed in cats.

An enzyme-linked immunoassay for the detection of antibodies to the mouse mammary tumor virus: application to human breast cancer

An enzyme-linked immunoassay (ELISA) was developed, using the mouse mammary tumor virus (MMTV) fixed to wells of a microtiter plate, for the determination of antibodies to MMTV. The intensity of the final color change was dependent upon virus or viral antibody concentration. MMTV antibody was readily detectable in sera diluted as much as 1 : 2800. Fixed MMTV bound antibodies to an internal viral protein (p 28) as well as to viral envelope components (gp 52, gp 34), demonstrating that the virus was rendered permeable by our procedure. Applying this assay to human sera, significant differences (P less than 0.005) in IgG binding to MMTV were detected between sera of breast cancer patients, benign breast disease patients and healthy individuals. 26% of breast cancer-derived sera contained MMTV binding antibody; 10% of benign sera or 8% of normal sera were also positive. The reactivity of human IgG with MMTV was blocked by prior incubation of the virus with antisera to gp 34 or, to a lesser extent, with gp 52. The results demonstrate that MMTV antibodies can be quantitated by this simple, rapid and inexpensive procedure.

Virolysis of mouse mammary tumor virus by sera from breast cancer patients

All type C retroviruses are lysed by human serum in apparently antibody-independent, complement-mediated reactions. In contrast, we have now determined that the mouse mammary tumor virus (MMTV), a type B retrovirus, is not disrupted by normal human serum. MMTV was lysed, however, when rabbit antibody to whole MMTV was added to the serum. By taking advantage of this dependence of MMTV lysis on specific antibody, a virolytic assay was developed, based on the measurement of reverse transcriptase released from disrupted virions, to search for evidence of antibodies to MMTV in human sera. Significantly greater virolytic activity was detected in the sera of patients with breast cancer than in sera of patients with benign disease (P less than 0.001) or colorectal cancer (P less than 0.001) or in sera from apparently healthy individuals (P less than 0.002). This assay thus appears to be able to detect a unique attribute, possibly the presence of an antibody crossreacting with MMTV, in serum in patient with breast cancer.

A nuclear DNA polymerase in bull spermatozoa

A DNA polymerase was isolated from bull spermatozoa by differential centrifugation, ultrafiltration and gel filtration. Its apparent molecular weight and synthetic template utilization resemble that of DNA polymerase gamma. Chemical and enzymic fractionation of bull spermatozoa indicate that the enzyme is most probably located in the nucleus.

Inhibition of human seminal fluid DNA polymerase by an IgG fraction of seminal plasma from vasectomized men

Immunoglobulin G (IgG) was isolated from ejaculates of intact and vasectomized men by precipitation with ammonium sulphate and DEAE-cellulose ionexchange chromatography. Velocity centrifugation revealed that all of the IgG from intact males was 7S protein while less than 40% of the seminal IgG of vasectomized men cosedimented with the 7S marker; the remaining, immunologically unidentifiable, protein was considerably smaller and heterogeneous in size. Only the 7S IgG from the post-vasectomy ejaculates inhibited the activity of a DNA polymerase from the seminal fluid of an intact male. These results suggest that formation of antibody reactive with the seminal fluid DNA polymerase is one manifestation of a vasectomy-associated autoimmune response in man.

Inhibition of viral reverse transcriptase and human sperm DNA polymerase by anti-sperm antibodies

The IgG fraction of serum from a rabbit immunized with detergent-prepared human sperm nuclei inhibited the DNA polymerase activities in human sperm and seminal fluid as well as the partially purified reverse transcriptase of the baboon endogenous type-C retrovirus (BEV). The analogous enzymes from lysates of oncogenic type-C viruses was unaffected. IgG from the serum of individual partners from infertile marriages similarly inhibited both purified BEV reverse transcriptase and human sperm DNA polymerase, but not a DNA polymerase isolated from human prostatic fluid. The data suggest that BEV reverse transcriptase and the human sperm DNA polymerase are antigenically related. Furthermore, the sperm appears to be auto-antigenic and the antibodies thus formed may be capable of interfering with reproductive success.