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N J Alexander

Publications and source records attributed to N J Alexander.

At least 73 records · Page 4Linked to original sources

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.

Animals↗

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.

Autoantibodies↗

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.

Animals↗

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.

Acrosome↗

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.

Animals↗

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.

Female↗

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.

Autoanalysis↗

Monoclonal antibodies to human trophoblast and sperm antigens: report of two WHO-sponsored workshops, June 30, 1986--Toronto, Canada.

Two WHO-sponsored workshops were recently held to obtain a consensus view from researchers active in the field of reproductive immunology on the current status of the application of monoclonal antibodies to studies of molecular events underlying reproduction and to determine the feasibility of using this approach to identify trophoblast- or sperm-specific antigens that might represent suitable candidates for the development of antifertility vaccines. A total of 66 mouse monoclonal antibodies reacting with human sperm and 45 monoclonal antibodies reacting with human trophoblast membrane components were submitted by 29 laboratories. These were evaluated in coded form by 42 laboratories with the appropriate expertise in biochemistry, immunohistology and tests of reproductive cell function. The majority of both anti-sperm and anti-trophoblast monoclonal antibodies cross-reacted with cellular elements in non-reproductive tissues. However, at least five monoclonal antibodies (two anti-trophoblast and three anti-sperm) appeared to demonstrate sufficient specificity to warrant further investigation as reagents for the identification of antifertility vaccine candidates.

Antibodies, Monoclonal↗

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.

Autoantibodies↗

Rectal infusion of semen results in transient elevation of blood prostaglandins.

Repeated semen deposition in the gut may be linked to the development of viral infections in homosexual men. Other investigators have suggested that rectal insemination may diminish immune responsiveness. We approximated conditions of human insemination by infusing 2 ml of pooled human seminal plasma (SP) into the rectum and/or vagina of rhesus monkeys. This resulted in increased blood plasma concentrations of the bicycloderivative of prostaglandin E (PGEM-II) which reached peak concentrations 2 h after rectal SP instillation in seven of eight test monkeys, but not the controls. The rate of PGE2 diffusion appeared to occur more rapidly across vaginal than rectal mucosa. Suppression of peripheral cellular immune functions was not demonstrated after the single exposure of this study, although persistent and repeat exposures could lead to local or generalized suppression of host defense mechanisms. Absorption of PGE's from the gut may be a cofactor in the development of sexually transmitted viral diseases.

Animals↗

EBV transformation and microfusion as the potential source of human monoclonal antisperm antibodies.

Peripheral blood lymphocytes were obtained from vasectomized men with high serum titers of antisperm antibodies. An Epstein-Barr virus (EBV) transformation was performed either with B cells or mononuclear leukocytes. The effect of feeder cells (irradiated umbilical cord blood lymphocytes), cyclosporin A, and in vitro stimulation of lymphocytes with sperm extract on EBV transformation was evaluated. Antibody-producing cells were screened for specificity against human sperm by an enzyme-linked immunosorption assay (ELISA) one to six weeks after transformation. Using B cells or leukocyte mononuclear cells, we found that the percentage of wells containing antibody reactive against human sperm was greatest two weeks after transformation (range 3% to 7.5% positive wells). To increase and maintain antibody synthesis by these transformed cells, microfusions were performed in those wells positive for antisperm antibody using the UC 729-6 lymphoblastoid cell partner. Then resultant hybridomas were expanded, subcloned, and preliminarily characterized.

Antibodies, Monoclonal↗

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.

Cell Separation↗

The type of dietary fat affects the severity of autoimmune disease in NZB/NZW mice.

The type of dietary fat dramatically affects the onset of autoimmune disease in lupus-prone female New Zealand Black/New Zealand White F1 (B/W) mice. Disease development was strikingly slowed in mice fed a diet containing quantities of omega-3 fatty acids (fish oil, FO). By 10 months of age, 94% of the FO mice were still living, whereas all the mice fed a saturated fat diet (lard,L) were dead. Those mice fed a corn oil (CO) diet were intermediate with 35% alive at the 10-month time evaluation. Long after the L and CO groups had succumbed to glomerulonephritis, the FO group had negligible proteinuria. Both B and T cell function, particularly antibody production and resultant circulating immune complex (CIC) levels, were modified by the type of dietary fat. FO mice exhibited lower levels of anti-ds-DNA and lower levels of CICs than L or CO mice. B/W antibody response to a T-independent antigen (DNP-dextran) was enhanced at 8 months of age in FO mice, whereas it was suppressed in L mice. T-dependent (sheep red blood cell) responses at that time period were reduced in all the diet groups, a reflection of the reduced numbers of accessory T cells as determined by FACS analysis. The natural killer (NK) response to YAC-1 cells decreased in the L group from 5 to 9 months of age but remained unchanged in the CO and FO groups. Severe glomerulonephritis was the most common histopathologic finding in the L and CO groups. Arteritis was found in the spleens of nearly all the L and CO mice. Arteritis of the heart, colon and intestine, stomach, kidney, and liver were also seen principally in the L mice. In contrast, most FO mice had minimal to mild glomerulonephritis and no or minimal arteritis in the spleen. It is likely omega-3 fatty acids of fish oil reduce immune-complex-induced glomerulonephritis through production of prostaglandin metabolites with attenuated activity and/or through altering cell membrane structure and fluidity, which may, in turn, affect the responsiveness of immune cells.

Animals↗