Mouse monoclonal antibodies against human sperm: evidence for immunodominant glycosylated antigenic sites

Thirty mouse monoclonal antibodies (MoAbs) raised against human sperm detect common antigenic determinants on human lymphocytes, erythrocytes, bacteria and endotoxin. Specific chemical, enzymatic and lectin blocking studies indicate that the sperm-associated antigens defined by these MoAbs are glycoconjugates. Further studies including reactivity of these MoAbs with organic sperm extracts indicate that the predominant carriers of these carbohydrate antigens are glycolipids and that the terminal immunodominant monosaccharide may be N-acetyl-glucosamine or N-acetylgalactosamine.

Genital mucosal transmission of simian immunodeficiency virus: animal model for heterosexual transmission of human immunodeficiency virus

An animal model for the heterosexual transmission of human immunodeficiency virus (HIV) was developed by the application of simian immunodeficiency virus (SIV) onto the genital mucosas of both mature and immature, male and female rhesus macaques. Virus preparations were infused into the vaginal vaults or the urethras (males) of the animals through a soft plastic pediatric nasogastric feeding tube. The macaques that were infected by this route (six males and nine females) developed SIV-specific antibodies, and SIV was isolated from peripheral mononuclear cells of all seropositive animals. One male and one female infected by this route developed severe acquired immunodeficiency syndrome-like disease with retroviral giant-cell pneumonia. As few as two inoculations of cell-free SIV containing 50 50% tissue culture infective doses induced persistent viremia. Cell-free virus preparations were capable of producing infection by the genital route. Much higher doses of virus were required to transmit SIV by this route than are required for transmission by intravenous inoculation. Thus, it appears that the mucous membranes of the genital tract act as a barrier to SIV infection. Spermatozoa and seminal plasma were not required for the genital transmission of SIV. Rarely, SIV was recovered from mononuclear cells in semen and vaginal secretions. The SIV-rhesus macaque model is suitable for assessing the role of cofactors in heterosexual transmission of HIV and will be useful for testing the effectiveness of spermicides, pharmacologic agents, and vaccines in preventing the heterosexual transmission of HIV.

Production of large amounts of mouse polyclonal antisera

A simple and inexpensive method for producing larger volumes of mouse polyclonal antisera is described. Groups of BALB/c mice were immunized with different human sperm antigens classified according to molecular weight. Mice were immunized twice with the antigen, twice pristane pretreated, and then injected with a non-antibody-secreting myeloma cell line to induce ascites formation. Antibody activity of the ascites fluid approximated that of the serum. Thus, one mouse can provide about six times the amount of antibody-containing fluid usually obtained after conventional immunization. This method also may be applicable for ascites fluid production in nude mice.

Distribution of T cell subsets in follicular fluid

Examination of follicular fluid (FF) from in vitro fertilization patients revealed a significant difference in concentrations of lymphocytes and T cell subpopulations with increased oocyte maturation. A total of 111 follicles containing 82 oocytes were aspirated from 10 patients undergoing laparoscopic oocyte retrieval. FF from 61.3% of the follicles was classified as clear and 38.7% as bloody, based on gross and microscopic appearance. A mean of 1.78 X 10(6) lymphocytes/ml was obtained from peripheral blood (PB) as compared to 2.14 X 10(5) and 2.79 X 10(5) lymphocytes/ml for clear and bloody FF, respectively. There were 6.3 X 10(5) T4 and 3.7 X 10(5) T8 lymphocytes in PB, resulting in a T4/T8 ratio of 1.72, which is not significantly different from that of the general population. The mean concentration of FF T4 and T8 lymphocytes decreased with increased oocyte maturation; the T8 reduction was statistically significant (P less than 0.05). The proportion of T4 to T8 lymphocytes in FF remained unchanged and was unaffected by maturity of the oocyte. Although estradiol (E2) did not vary with oocyte maturity, progesterone (P) increased and E2/P decreased. There was no correlation between E2 or P levels and distribution of T cells. Fertilization rates were higher in more mature oocytes, but there was no correlation between fertilization and E2, P, E2/P, or T cell subpopulations. It remains to be determined what factors result in the decrease in lymphocytes with increased oocyte maturity and the observed difference in FF T4/T8 compared to PB.

The effects of antibody sperm-egg interaction

Previous studies have shown that high titers of antisperm antibodies are correlated with low fertility. Furthermore, immunosuppressive therapy enhances pregnancy in some individuals. Serum tests, however, provide only an indirect measure of a potential pool of antisperm antibodies. When men have antibodies, direct measurement of the percent of sperm that are entirely antibody bound is a more appropriate approach. Antibodies can affect fertilization at many sites. Since sperm are composed of numerous antigens, many antibodies can develop but not all of them will interfere with infertility. Better tests are necessary to define which antibodies may affect fertility. To do that requires the development of better antigens. Use of monoclonal antibodies allows a framework for such further modifications.

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.

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.

Evaluation of semen parameters by means of automated sperm motion analyzers

Fresh semen specimens from 46 patients and donors were evaluated for concentration, motility, velocity, and linearity using two different commercially available computerized sperm motion analyzer systems. Although no significant differences in measurement of concentration or motility were observed, significant differences in velocity and linearity were recorded. Fourteen cryopreserved/thawed samples were assessed with the same set-up parameters as fresh specimens. When discrepancies between manual and computer counts were noted, the authors changed the set-up parameters and evaluated 33 additional specimens. Again, no differences in concentration and motility, but significant differences in velocity and linearity were observed. Interlaboratory results must be correlated and standardization of set-up parameters of various analyzers is essential.

Seminal plasma antigens detected by immunoblotting with human sera from vasectomized males

Eighty-seven serum samples from vasectomized men and 10 samples from normal men were analyzed by immunoblotting for auto-antibodies against seminal plasma proteins. Auto-antibodies against seminal plasma were present in 53 out of 87 vasectomy serum samples. Seminal plasma electrophoresed under non-reduced conditions revealed major antigens at 35 and 68 kDa recognized by auto-antibodies. Whereas under reduced conditions auto-antibodies recognized to a variable degree many more antigens having apparent molecular weights of 20, 22, 35, 40, 45, 65, 68, 70 and 75 kDa. None of the sera reacted only with reduced or non-reduced samples. The results of sperm agglutination and sperm immobilization tests correlated with no specific molecular weight antigen. Many of the recognized antigens were glycoprotein. The reactivity of the auto-antibody to the seminal plasma antigens is specific and could not be blocked by prior adsorption of the serum samples with liver powder or human sperm.

Dietary fat modulation of in vitro lymphocyte function

Mitogen responsiveness of spleen cells from NZB/NZW mice fed one of three defined diets was compared. The fat source of one diet was 20% lard (L, saturated fat), the second 20% polyunsaturated (corn oil), and the third 20% polyunsaturated (fish oil, FO). No differences in stimulation indices were observed. To determine whether the lipid components in media serum supplements were altering our results, we compared splenic mitogen responses in nonautoimmune mice fed either the FO or the L diet with in vitro culture in serum-free medium, alone, or with different serum supplements. Supplements included 10% fetal calf serum and 1 and 5% mouse sera from rodent chow-fed, L-fed or FO-fed mice. Spleen cells from BALB/c mice fed FO had consistently lower stimulation levels as compared to the other diet groups regardless of media supplementation. Capping experiments designed to directly assess membrane fluidity in lymphocytes from mice fed either the L, FO or lab chow diets revealed no differences. Although in vitro membrane turnover undoubtedly occurs during blastogenesis, we found that culturing cells in media with different serum supplements did not alter relative mitogen responses.

Therapeutic insemination

Except in special circumstances, therapeutic insemination with a husband's sample has a low success rate. Couples in whom oligozoospermia has been identified as the principal cause of infertility do not benefit from therapeutic insemination by husband. Because of this low success rate, intrauterine insemination to provide sperm in closer proximity to the egg has become popular, but intrauterine insemination also has a low success rate. We suggest that intrauterine insemination should be approached aggressively in cases of male factor infertility. The recipient should be stimulated to enhance egg production and closely monitored for ovulation. A semen specimen of not less than 1 X 10(6) motile sperm with antibiotics added should be placed in the uterus the day after ovulation. If no pregnancies occur within four cycles, alternate approaches should be considered. Therapeutic insemination by donor involves careful donor selection to avoid inheritance of malformations and familial diseases. Because of the possibilities of sexually transmitted diseases, careful and repeated screening should be conducted. A complete sexual history should be obtained, and donors should be excluded if they have had any homosexual contact since 1978, if they have been an intravenous drug user, if they come from a geographic area where the sex ratio of AIDS is close to 1:1, or if they have recently had multiple sexual partners. A permanent record preserving the confidentiality but allowing the tracing of genetic anomalies, even if not present at birth, should be kept.