Monoclonal antibody recognizing an apparent peptide epitope of human seminal plasma glycoprotein and exhibiting sperm immobilizing activity

A hybridoma (3B2-F7) has been established which secretes a monoclonal antibody (Mab) directed against a peptide determinant of human seminal plasma glycoprotein (HSP-gP). The deglycosylation of HSP-gP was performed chemically with TFMS hydrolysis and enzymatically in the presence of detergent and further treated with periodic acid after fixing deglycosylated HSP on plastic wells. The Mab 3B2-F7 (IgM, kappa) exhibited sperm immobilization activity (256 units of SI50) and inhibited sperm binding to human zona pellucida. Human epididymis, pancreatic islets of Langerhan's and distal tubulus of kidney were strongly labelled whilst other tissues were essentially negative by avidin-biotin complex tissue staining with this Mab. The antigen epitope to the Mab was in the 36 kDa molecule of human HSP-gP. The antigenic determinant recognized by Mab 3B2-F7 was destroyed by six different proteases, but was resistant to N-glycanase and other carbohydrate splitting enzymes. This epitope is therefore likely to be composed of a polypeptide chain. Peptide fragments after proteolysis of the HSP molecule with Staph. aureus V8 protease and trypsin retained antigenicity, hence the epitope corresponding to the Mab may be a peptide chain and not dependent on the conformational structure of the polypeptide.

[Reverse passive hemagglutination assay for human chorionic gonadotropin in urine using monoclonal antibody]

Aiming to find a urinary hCG immuno-assay which is specific, sensitive and easy to perform, a reverse passive hemagglutination reaction was studied by using sheep red blood cells (SRBC) coupled with monoclonal antibodies (Mab) to hCG. Three Mabs (5D4, 6E4, 2F8) with different specialty were used for the study. Mab 5D4 reacted to hCG, hCG-beta, and LH but not to hCG-alpha. Mab 6E4 reacted to hCG, hCG-alpha and LH, but not to hCG-beta. Mab 2F8 reacted to hCG but not to hCG-alpha, hCG-beta, or LH. All three Mabs were IgG1. SRBC were treated with glutaraldehyde and then with tannic acid. These treated SRBC were coupled with IgG(2mg/ml) of each anti hCG-Mab. For assays, 30 microliters of 1:1 mixtures of two different Mab-coupled SRBC and 30 microliters of standard hCG or urine samples were mixed in wells of microtiter plates and reacted for 60 min at room temperature. Among three different combinations, the couple 5D4-SRBC and 2F8-SRBC were most sensitive and specific for hCG assays and the minimum amount of hCG and LH detected in this combination assays was 12.5 mIU/ml and 800 mIU/ml, respectively. Some clinical data obtained by applying this assay were presented.

[Role of sperm passage through cervical mucus: fertilizing capacity tested by in vitro fertilization with zona-free hamster eggs]

The effect of sperm passage through cervical mucus (CM) on the fertilizing capacity of human spermatozoa was examined in the in vitro fertilization system of zona-free hamster eggs. Each drop of ejaculated semen and BWW culture medium was connected by a small capillary tube filled with preovulatory CM, egg white or BWW medium under liquid paraffin oil in a plastic petri dish. After 2 hours, zona-free hamster eggs were added to the drop of BWW culture medium containing spermatozoa which had passed through the capillary tube and the mixture was incubated for various lengths of time at 37 degrees C under 5% CO2 in air. Human spermatozoa, which were washed and preincubated for 2 hours in BWW medium, were capable of fertilizing zona-free hamster eggs but needed a longer incubation time than spermatozoa which had passed through CM. Fertilization rates of spermatozoa which had passed through CM and egg white were very similar, but no fertilization occurred in the drop containing spermatozoa which had passed through BWW medium, presumably because of the contamination with seminal plasma. These results indicate that the most important role of CM may be to separate motile spermatozoa from seminal plasma components hostile to fertilization.

Techniques for sperm immobilization test

Several semiquantitative, quantitative, and microassay techniques had been developed to detect antibodies bound to human spermatozoa: sperm agglutination test (SAT), sperm immobilization test (SIT), immunofluorescence test, radioantiglobulin test, enzyme-linked immunosorbent assay (ELISA), mixed erythrocyte-spermatozoa antiglobulin reaction (MAR), "Panning" test, and immunobead test (IBT). Clinical application of these techniques include (a) detection of sperm immobilizing antibodies in sera of sterile women, (b) follow-up study of sperm immobilizing antibodies, and (c) detection of sperm immobilizing antibodies in cervical mucus and other secretions. The chemical structure of antigen epitope corresponding to Mab H6-3C4 may recognize the internally located repetitive unbranched N-acetyllactosamine structure, regardless of terminal substitution at Gal (i.e., sialyl-i as well as i structure). The majority of sperm-immobilization (SI) positive women's sera were absorbed with carbohydrate components on ejaculated sperm, but only one serum competed with Mab H6-3C4 on binding to sperm except a serum from whom lymphocytes were donated to make Mab H6-3C4. The SI agglutinating antibodies (Abs) in women's sera were raised to the carbohydrate epitopes of glycoprotein in HSP, but epitopes might have several different conformational structures. Studies are in progress to find whether or not SI-Abs could be generated to peptide epitope of human seminal plasma (HSP) or sperm.

Characterization of epitopes of seminal plasma antigen stimulating human monoclonal sperm-immobilizing antibodies: a personal review

In observations made between 1974 and 1984, 40 of 303 women with unexplained sterility (13.2%) showed positive sperm-immobilizing antibodies. Among many kinds of antibodies to human sperm including sperm coating antigens, the biologically active antibodies, such as sperm-immobilizing agglutinating antibodies and blocking antibodies for fertilization, could be relevant to infertility. Harmless sperm-binding antibodies are present even in the sera and cervical mucus of fertile women. Antigens corresponding to monoclonal antibodies (1C4, 2C6, 2E5), which were generated to human sperm coating antigens and indicated strong sperm-immobilizing activities, seemed to have carbohydrate epitopes. The majority of women with sterility of unknown cause appeared to raise sperm-immobilizing antibodies to carbohydrate epitopes of sperm. The stable human-mouse heterohybridoma H6-3C4 secreting monoclonal antibody (IgM, lambda) with extremely high titres of sperm-immobilizing (SI50, 5000 units) and agglutinating (1:1600) activities was successfully established from peripheral lymphocytes of a sterile woman. The chemical structure of an antigen epitope corresponding to human monoclonal antibody H6-3C4 was found to consist of internally repetitive, unbranched N-acetyllactosamine (blood type i antigen). Ejaculated human sperm appeared to be densely covered with sialyl blood type i antigen and sialyl branched internally repetitive N-acetyllactosamine (sialyl blood type I antigen). The antibody-producing V-H and V-L genes of the human hybridoma H6-3C1 were cloned and preserved to stabilize antibody production. Class-switch variants of heavy chain from mu to gamma (IgG1, lambda) in human Mab H6-3C4 were produced by recombinant DNA technology.

Characterization of a small immunoreactive HCG-like component isolated from urine of a patient with choriocarcinoma

An immunoreactive hCG-like substance with low molecular weight was isolated from the urine of a patient with choriocarcinoma and its characteristic properties were studied. The urinary hCG preparation was fractionated by gel filtration on a Sephadex G75 column and each fraction was assayed for hCG activities by an enzyme linked immunosorbent assay using a monoclonal antibody to hCG (Mab-5D4). Two immunoreactive hCG peaks were obtained. One was coeluted with ordinary hCG and the other was eluted after hCG-alpha. After refractionation on the same column, the hCG peak (Ag-2) with low molecular weight was radioiodinated with 125INA and applied to an immunoaffinity column bound Mab-5D4 for further purification. The purified 125I-labelled Ag-2 showed a high binding activity to a conventional rabbit anti-hCG serum and Mab-5D4. This Mab had binding specificity to hCG, hCG-beta and LH but not to hCG-alpha. However, this fraction did not bind to Mab-6E4 which possessed binding activities only to hCG, hCG-alpha and LH, nor to Mab-2F8 which was specific only to hCG. Autoradiography after SDS-Page of the immune precipitate which was made by 125I-labelled Ag-2 and Mab-5D4, revealed that the Ag-2 had a molecular weight of approximately 14,000 daltons. Lectin (LeH) affinity chromatography of the urinary hCG specimen from the same patient revealed that it contained two kinds of immunoreactive hCG. One did not bind to LeH column but the other did. A small immunoreactive molecule (Ag-2) was detected in the LeH-unbound fraction but not in the LeH-bound fraction. These results suggest that choriocarcinoma patients excrete in the urine a small LeH-unbound immunoreactive component which contains an antigen epitope common to hCG, hCG-beta and LH.

Immunogenicity of a 92kDa component of porcine zona pellucida isolated using a monoclonal antibody (3A4-2G1) exclusively cross-reactive with porcine and human zonae pellucidae

Three monoclonal antibodies (Mabs) to solubilized porcine zona pellucida (s-PZP) were produced. They reacted exclusively to porcine and human zonae pellucidae (ZPe) and two of them blocked sperm penetration of ZP in humans by collaborating with goat anti-mouse gamma-globulin serum as a second antibody. The antigen corresponding to one of these Mabs (Mab 3A4-2G1) was fractionated from s-PZP by immunoaffinity chromatography bound Mab 3A4-2G1. The antigen corresponding to Mab 3A4-2G1 was further fractionated by SDS-PAGE and the protein band corresponding to 92kDa was found to react to Mab 3A4-2G1, as demonstrated by Western blotting. The 92kDa fraction of s-PZP was isolated and injected into mice with complete and incomplete Freund's adjuvants to obtain an antiserum. It was shown that the antiserum to the 92kDa molecule reacted in a tissue-specific manner to human ZP and exhibited a strong inhibitory effect on sperm penetration of ZP of human oocytes.

[Bovine cervical mucus as a substitute of human cervical mucus]

The sperm penetration test (SPT) in cervical mucus (CM) is an important test in screening for sperm-CM incompatibility. For a routine SPT, a sufficient amount of preovulatory CM is necessary, but the amount of human CM is often inadequate. We examined estrous bovine CM as a substitute for human CM in the SPT. Preovulatory human CM and estrous bovine CM were collected and stored frozen at -20 degrees C until use. After being thawed at room temperature, the two CM samples were compared as to their pH, spinnbarkeit and ferning patterns, and it was found that they are quite similar. In Kremer's method of SPT, sperm penetration distance, density and motility were similar in human and bovine CM for 12 hours, but thereafter sperm motility became much lower in bovine CM than in human CM. The results of SPT with spermatozoa from patients with oligozoospermia were quite similar in both CMs. When spermatozoa pretreated with antisperm antibody were used for SPT, sperm penetration was completely blocked in human CM, but no inhibition was seen in bovine CM. From these results, we conclude that bovine CM can be substituted for human CM for some, but not all, purposes.

Human sperm carbohydrate antigens defined by an antisperm human monoclonal antibody derived from an infertile woman bearing antisperm antibodies in her serum

The epitope structure of the human sperm antigen reacting with antibodies present in sera of infertile women has been studied using mAb H6-3C4, which produces immobilization of human sperm in the presence of complement. Another antibody, NUH2, which also induces human sperm immobilization, was used to substantiate the presence of a receptor on sperm involved in susceptibility to immobilization. Both antibodies defined type 2 chain polylactosamine structure. H6-3C4 is directed to internally located repetitive N-acetyllactosamine, i.e., sialyl-i, i, or fucosyl-i. NUH2 defines binary alpha 2----3 sialyl type 2 chain, i.e., sialyl-I. Thus, the presence of antibodies in the sera of infertile women directed to sperm lactosaminoglycan or lactosaminolipid could be the basis for infertility in these cases.

Application of the quantitative sperm immobilization test for follow-up study of sperm-immobilizing antibody in the sera of sterile women

For quantitative estimation of sperm immobilizing antibody, a new assay method was developed and applied to a follow-up study of antibody titers in the sera of sterile women. The 50% sperm immobilization units (SI50) estimated by the quantitative method ranged from 1.2 to 97.3 in the sera from 16 sterile women who showed relatively high antibody activities in the previous semiquantitative sperm immobilization test. When the quantitative antibody titers, SI50, were followed over 3 years in sterile women with the sperm immobilizing antibody, the antibody titers were found to be unstable, and undulated over a period of several months. Therapy consisting of use of a condom seemed to be ineffective in decreasing the antibody titers.

Analyses of epididymal sperm surface antigens by monoclonal antibodies against hamster spermatozoa

BALB/c mice were immunized with spermatozoa from cauda epididymides of hamsters and the immune spleen cells were fused with mouse myeloma cells (P3U1). Seven hybridomas (GHS-1,-2,-3,-4,-5,-6, and -7) that produced monoclonal antibodies (Mabs) binding to the epididymal spermatozoa were established. Three Mabs (GHS-3,-4, and -6) were IgM and the other four were IgG1. All Mabs reacted to hamster spermatozoa from cauda epididymides but none of the Mabs except GHS-5 and -7 reacted to spermatozoa in testis. GHS-5 and -7 Mabs bound to the acrosome region of spermatozoa in both testis and epididymis. The antigens corresponding to GHS-2, -4, and -6 Mabs appeared to be excreted from epithelial cells of caput epididymis, while those to GHS-1 and -3 Mabs seemed to be produced in cauda epididymis. Both groups of the antigens bound to the surface of spermatozoa during their epididymal transit. Immunoblotting analyses of epididymal fluid showed that the antigen epitopes corresponding to GHS-1,-2,-3,-4, and -6 Mabs were distributed to multiple components with different molecular weights ranging from over 100 to 25 kd. The distribution patterns of the epitopes corresponding to GHS-1 and -3 Mabs and GHS-2,-4, and -6 Mabs were very similar, respectively, but each group pattern was quite different from each other. GHS-5 Mab reacted to a component of sperm extract with a molecular weight of around 94 kd, while GHS-7 Mab failed to recognize any components transblotted.

Production of heavy-chain class-switch variants of human monoclonal antibody by recombinant DNA technology

We have previously established a human-mouse heterohybridoma (H6-3C4), which produced a human sperm-immobilizing antibody (mu, lambda of human type). The human rearranged immunoglobulin mu-chain and lambda-chain genes were cloned from the hybridoma H6-3C4. The cloned V region of the heavy chain (VH) gene was ligated to human immunoglobulin gamma 1-heavy chain constant region (C gamma 1) genes. This resulted in the heavy-chain class-switch from mu-chain to gamma 1-chain of H6-3C4 antibody. The class-switched heavy-chain gene as well as the cloned lambda-chain gene were introduced into mouse myeloma cell line X63Ag8.653 by protoplast fusion and electroporation. The stable transformants produced the human IgG monoclonal antibody, which fully retained specificity to human sperm cells and sperm-immobilizing activity.

Establishment of a murine monoclonal antibody against human clear cell carcinoma and analysis of the corresponding antigen

A murine monoclonal antibody (Mab) 4B6, immunoglobulin M (IgM), lambda chain, against human clear cell carcinoma of the ovary was established. Mab 4B6 reacted specifically to clear cell carcinomas, but failed to react to other types of ovarian carcinomas, such as mucinous, serous carcinoma, and also failed to react to human normal organ tissues. Mab 4B6 recognized antigenic determinants located on the membranes of carcinoma cells. Antigenic substances corresponding to Mab 4B6 were detected in sera of patients with ovarian clear cell carcinoma by using Sandwich radiometric assays performed with Mab 4B6-coated microplates and 125I-Mab 4B6. Gel filtration on Sephacryl S-300 revealed that the antigen corresponding to Mab 4B6 possessed a molecular weight of 50 to 60 kDa. Furthermore, after periodic acid and enzyme treatments, it was suggested that the antigen epitope corresponding to Mab 4B6 contains a carbohydrate moiety.

[Successful application of in vitro fertilization and embryo replacement in the treatment of infertile women with sperm immobilizing antibody]

Thirteen infertile patients (18 cycles) with sperm immobilizing antibodies were subjected to in vitro fertilization and embryo replacement (IVF-ER) therapy during 12 months from January to December 1985. Four patients became pregnant, two of them delivered healthy babies at term and 2 had abortions at 5 weeks and 12 weeks of gestation, respectively. In the same duration, 24 patients (28 cycles) with tubal factor and 4 patients (5 cycles) with male factor for infertility were subjected to IVF-ER, and two patients with tubal factor became pregnant and delivered healthy babies at term. In the patients with immunological factor, fertilization and cleavage rates per mature oocyte were 85.9% (55 fertilized/64 oocytes) and 81.3% (52 cleaved/64 oocytes) respectively, while the fertilization rates in patients with tubal factor and male factor were 70.5% (62 fertilized/88 oocytes) and 50.0% (6 fertilized/12 oocytes) respectively and all fertilized eggs in these patients developed to the cleavage stage. Thus fertilization and cleavage rates for mature oocytes from the patients with the immunological factor were slightly better than those with the tubal factor and much better than those with the male factor. The antisperm antibody titers (SI50) in sera determined by the quantitative sperm immobilization test ranged from 20 to 243 units while those in follicular fluids ranged from 21 to 160 units in the patients with the immunological factor. The follicular sperm immobilizing antibodies could be detected in any patient who had the antibodies in the serum. Immunoglobulin (IgG, IgA, IgM) concentrations in follicular fluids were not significantly different from each other in the patients with immunological, tubal and male factor for infertility.

Successful delivery in a female with thrombotic thrombocytopenic purpura

A 28-year-old female, who suffered from thrombotic thrombocytopenic purpura (TTP) in the 14th week of her first pregnancy, recovered after a plasma exchange followed by an induced abortion. From six months after the abortion, she no longer required plasma infusions every 3-4 weeks to prevent a relapse of TTP manifested as thrombocytopenia, and complete remission continued until her next pregnancy. In her second pregnancy, she had an immediate relapse of TTP and responded to plasma infusion until the 24th week. However, the TTP gradually became resistant to plasma infusion, and developed into toxemia with edema, hypertension and proteinuria in the 27th week. Although the TTP was alleviated by the infusion of large amounts of plasma, the placenta failed as the result of numerous white infarcts. She delivered a 948 g live baby by cesarean section in the 33rd week. The baby had transient thrombocytopenia but did not suffer from TTP. The mother required plasma infusions every 3-4 weeks for about five months, and she has continued in remission.

Identification of an H antigen-like blood group antigen in sera of cancer patients using a novel monoclonal antibody raised against endometrial carcinoma

An IgM class monoclonal antibody (MAb) was derived by immunizing BALB/c mice with a human endometrial carcinoma cell line. This MAb, termed C12, exhibited strong reactivity against endometrial carcinoma, but lesser reactivity against normal endometria. The antigen recognized by MAb C12 (C12 antigen) was detected by radiometric assay in sera from patients with various carcinomas, but not in sera from patients without carcinomas or in sera from normal individuals. MAb C12 was found to agglutinate blood type O erythrocytes, but not A, B, or AB erythrocytes. To clarify the specificity of MAb C12, tissue staining experiments were performed in parallel using MAb C12, Ulex europaeus lectin I (anti-H), and a monoclonal anti-H antibody. In endometrial carcinoma tissues, both H and C12 antigens increased, but the C12 antigen showed a prominent increase, in contrast to the H antigen. Further, the C12 antigen was not found in endothelial cells of blood type O patients. In sera, the level of the H antigen varied according to the host's blood type. The sera from blood type O individuals possessed higher levels of the H antigen than those with blood type A or B. Thus, the H antigen showed no value as a tumor-associated serum marker. In contrast, the presence of the C12 antigen in sera was not determined by ABO blood group status. Thus, MAb C12 was demonstrated to be a unique MAb that reacts with an H-like antigen occurring in the sera of patients with carcinomas irrespective of ABO blood group status. MAb C12 may prove to be a useful marker for cancer patient serum.

Establishment and characterization of a human hybridoma secreting monoclonal antibody with high titers of sperm immobilizing and agglutinating activities against human seminal plasma

Peripheral blood lymphocytes isolated from an infertile woman possessing strong sperm immobilizing and agglutinating antibodies were stimulated by culturing with poke-weed mitogen (PWM) and spermatozoa from a healthy donor for 5 days. The stimulated lymphocytes were fused with mouse myeloma NS-1 by PEG-1000. Fused growing hybrid cells were observed in 58 of 96 wells, and 22 of these showed the production of human immunoglobulin. Among the 22, one hybridoma clone (H6-3C4) was found to produce human IgM (lambda) with strong sperm immobilizing and agglutinating activities. The supernatant from the culture medium contained approximately 1.5 microgram IgM/ml and the antibody titers were 5000 SI50 units on sperm immobilization and 1:1600 dilutions on sperm agglutination. The hybridoma H6-3C4 has continuously produced high titers of antibody exhibiting sperm immobilizing and agglutinating activities over 8 months and contains chromosomes of acrocentric type from mouse and metacentric type from human. The monoclonal antibody (Mab) H6-3C4 reacted specifically to human seminal plasma, ejaculated spermatozoa and male accessory gland but not to testis, any other somatic tissues, or secreted fluids tested. Immunofluorescence staining indicated that the antigen corresponding to Mab H6-3C4 was present over the surface of ejaculated spermatozoa. The binding of Mab H6-3C4 to human spermatozoa was blocked by the serum of the patient from whom the lymphocytes were obtained for cell fusion.

Microimmunofluorescence using Terasaki plates and direct plate freezing method--rapid and reliable screening system of hybridomas

Microimmunofluorescence using Terasaki plates and a direct plate freezing method were combined for effective screening of hybridoma supernatants. The microplates, in which the fused cells (myeloma and spleen cells) were cultured and hybridoma colonies were growing, were frozen after harvest of supernatants and saved at -80 C for several weeks without affecting antibody production ability of hybridomas. Microimmunofluorescence was performed in Terasaki plates on which target cells were attached by poly-L-lysine and glutaraldehyde or by short time culture of the cells in Terasaki plates. The direct plate freezing method prevented initial hybridoma cells from changes or disappearance of antibody productions during screening of hybridoma supernatants; the microimmunofluorescence staining method permits fast and detailed estimation of specificity of antibodies of hybridomas by saving time and minimal consumption of supernatant for checking. The combination of these two methods is a powerful tool for obtaining desired monoclonal antibodies.

Affinity to lectin, biological and immunological characteristics of human chorionic gonadotropins from pregnant women and trophoblastic tumour patients

To compare the affinity to lectin of human chorionic gonadotropins (hCG) from pregnant women and trophoblastic tumour patients, a small amount of urine was fractionated by a lentil lectin (LcH) affinity chromatography. The LcH-bound fractions were eluted with 2% mannoside solution, and each fraction was assayed for hCG activities by radioimmunoassay. In pregnant women, more than 90% of hCG immunoactivity in urine was bound to the LcH column and eluted from it, whereas 8 to 26% and 37 to 51% of the activity were not adsorbed to the affinity column and were recovered in the LcH-unbound fraction in the patients with hydatidiform mole and choriocarcinoma, respectively. These results suggest that LcH affinity chromatography of urinary hCG contributes to differential diagnosis between pregnancy and trophoblastic tumours. To characterize the properties of hCG from the urine of choriocarcinoma patients, with or without the LcH affinity, hCG activities in both LcH-unbound and LcH-bound fractions were measured by in vivo and in vitro bioassays and each of the activities was compared with the activities measured by radioimmunoassay. The results showed that the LcH-unbound fraction contained hCG molecules defecting to induce the biological activity of hCG in vivo.

A human-mouse hybridoma producing monoclonal antibody against human sperm coating antigen

Since anti-sperm antibodies were first discovered in the sera of women, the relationship of these antibodies to sterility has been studied by many investigators. In order to determine the antigens of spermatozoa responsible for raising antibodies to spermatozoa in humans, many studies have been carried out by purifying human spermatozoa cell membrane and seminal plasma components. Since it was found that the purification was difficult by physiochemical procedures, the immunoaffinity chromatography bound monoclonal antibody (Mab) to spermatozoa antigens was attempted for this purpose. The establishment of hybridomas producing Mabs to human seminal plasma and human spermatozoa was reported by Shigeta et al. (1980), Isojima, Koyoma & Fujiwara (1982), Lee et al. (1982) and Isahakia & Alexander (1984). The ordinary approaches to obtain the Mabs consisted of xenogenic immunization with human semen and cell fusion of immunized spleen cells with mouse myeloma cells. However, the antigenic epitopes of human spermatozoa, which induced antibody production, are xenogenic for the mouse, and therefore there is a possibility that there is a difference in recognized antigenic epitopes in humans as isotypic and in mice as xenogenic. In order to study these antigenic epitopes, which correspond to antibodies against spermatozoa in women, the establishment of human-mouse hybridomas, which produced anti-semen antibodies as produced in sterile women, became essential. In these studies, we used recently developed cell fusion techniques to fuse immunized human peripheral lymphocytes with mouse myeloma cells.

The development of a contraceptive vaccine by purification of antigens from gametes

There are several ways to make immunological contraceptive vaccines. We are trying to purify gamete antigens from human seminal plasma and porcine zona pellucida (ZP) by using several monoclonal antibodies (Mabs) for this purpose. A human seminal antigen relevant to sperm immobilization with corresponding antibody was purified by immunoaffinity chromatography-bound Mab 1C4. This antigen was common to human milk protein but is different from lactoferrin. It was termed "ferrisplan" and was secreted mainly from the epithelial cells of seminal vesicle and adhered to the midpiece and postnuclear cap region of spermatozoa. Another Mab 2C6 reacted only to the SP component but not to other organ extract including human milk protein. The corresponding antigen to Mab 2C6 is aimed to purify by using high performance liquid chromatography and immunoaffinity chromatography-bound Mab 2C6. Several Mabs to porcine ZP antigens common to human ZP did not block human in vitro fertilization unless the second antibody (anti-mouse gamma-globulin) was used. It is speculated that porcine ZP will not contain the antigenic component that relates to sperm receptor of human ZP. Therefore, an antigenic molecule located close to sperm receptor of human ZP must be purified from the porcine ZP by using immunoaffinity chromatography-bound Mab and other biochemical methods, expecting production of a corresponding antibody that blocks the fertilization in humans.

[Production and characterization of a monoclonal sperm immobilizing antibody to seminal plasma antigens]

Rat spleen cells immunized to human azoospermic semen were fused with mouse myeloma cells (P3 X 63Ag8Ul) to obtain hybridomas which produce monoclonal sperm immobilizing antibodies. Of 114 hybrid clones obtained, 10 were found to produce antibodies with sperm immobilizing activity with complement. One clone (1C4) producing the highest antibody titer was chosen for further characterization. Chromosome analysis showed that 1C4 hybridoma cells contained two types of chromosomes which were derived from rat and mouse. Rat Ig was detected in both the cytoplasma and the culture medium of the cells by direct immunofluorescent test and immunodiffusion test, respectively. Gammaglobulin fractions from the culture medium had a strong sperm immobilizing activity and showed a common single precipitin line against human seminal plasma and human milk proteins. It was proved that the monoclonal antibody was produced to No. 7 antigen and not to No. 3 antigen (lactoferrin) in human seminal plasma, both of which have a common antigenicity to human milk proteins and compose the sperm coating antigens.

Identification of two different surface epitopes of human ovarian epithelial carcinomas by monoclonal antibodies

Monoclonal antibodies (Mabs) against human ovarian mucinous and serous carcinoma were obtained by the Mab technique. Their reactivities against human tumors were tested by indirect immunofluorescence. One of the Mabs, named 4C7, derived from the spleen cells of mice immunized with mucinous carcinoma line OVA-1, reacted to ovarian mucinous carcinoma, endometrioid carcinoma, and mesonephroid carcinoma but did not react to ovarian serous carcinoma. Another Mab, 3C2, obtained from the spleen cells of mice immunized with serous carcinoma line HOC-21, reacted to serous carcinoma and endometrioid carcinoma of ovary, but never reacted to mucinous carcinoma or mesonephroid carcinoma. Neither of the Mabs reacted to other types of ovarian carcinomas such as undifferentiated carcinoma, dysgerminoma, endodermal sinus tumor, and malignant teratoma of ovary, and also did not react to any benign ovarian tumors or other normal human tissues. Both Mabs 3C2 and 4C7 had no reactivity to carcinoma of other organs such as stomach, colon, lung, lymphoid system, and kidney and also did not react to human lymphocytic or carcinoembryonic antigen as confirmed by using many human cell lines and surgically resected samples. Since the cross-reactivities of these Mabs were limited within the ovarian epithelial carcinomas, it is suggested that two distinct epitopes are expressed on the ovarian epithelial carcinomas. One epitope, identified by Mab 4C7, is expressed only on mucinous carcinoma, endometrioid carcinoma, and mesonephroid carcinoma, while the epitope, identified by Mab 3C2, appears only on serous and endometrioid carcinoma.

Production and characterization of monoclonal antibodies to cross-reactive antigens of human and porcine zonae pellucidae

Three monoclonal antibodies (Mabs), 3A4-2G1, 1D5-2B7 and 1F2-1B8 were produced against heat-solubilized porcine zona pellucida (ZP). Each Mab stained intact ZP but no other pig tissues using immunofluorescence staining. All three Mabs stained selectively zonae pellucidae (ZPe) from pigs and humans but not from hamsters, rats or mice, and showed no inhibitory effect on sperm binding to human oocytes. When goat antiserum to mouse gamma-globulin was added to human oocytes pre-treated with 3A4-2G1 or 1D5-2B7, sperm binding to oocytes was completely blocked with formation of immune precipitates around them. SDS-PAGE analysis of the immune precipitates of 125I-labeled porcine zona proteins and Mab showed that the antigen binding 3A4-2G1 was mainly composed of components with approximate molecular weights of 92,000, 65,000 and 23,000 and the antigen binding 1D5-2B7 contained two components with approximate molecular weights of 57,000 and 49,000, respectively. The epitope of ZP antigen, corresponding to 3A4-2G1, was found to be present in the molecule of 92,000 daltons as demonstrated by enzyme immunostaining of the proteins after blotting to nitrocellulose membrane from SDS-PAGE gels.

[Detection of early pregnancy factor in the sera of conceived women before nidation]

In order to apply the early pregnancy factor (EPF) to early diagnosis of fertilization, the establishment of optimal conditions for assay of EPF was attempted, and then EPF in the sera of contracepted and conceived women 4 to 6 days after ovulation were measured. For assay of EPF, 0.25 ml of 1:2 step diluted anti-human lymphocyte serum (ALS), 0.05ml of guinea pig serum as complement and 0.1ml of lymphocytes suspension (1 X 10(7)/ml) pretreated with test serum were mixed and then incubated at 37 degrees C for 90 min. To this mixture 0.1ml of sheep red blood cell suspension (2 X 10(9)/ml) was added and the rosette formation was counted after centrifugation. The rosette inhibition titer (RIT) was expressed as reciprocal of ALS dilutions which resulted in less than 75% of rosette formation as compared with the control. RITs of the conceived women who were assayed on the 5 th day after ovulation were in the range from 16 to 32 X 10(3), while that of the control contraceptive women who were assayed on the same day was in the range from 2 to 4 X 10(3). The sterile women who received AIH but failed to conceive all showed less than 4 X 10(3) as RIT. These results suggest that the assay of EPF is valuable in detecting the early stage of fertilization and possibly may help to differentiate the impairment of embryo implantation from non-fertilization of the ovum as a cause of sterility.

Monoclonal antibodies to porcine zona pellucida antigens and their inhibitory effects on fertilization

Five hybridomas which produce monoclonal antibodies (Mabs) to porcine zona pellucida (ZP) were established. The immunoglobulin classes were IgG2a from hybridoma B11C8 and IgM from the other four. Using immunofluorescent staining, the Mab from B11C8 stained only porcine oocytes, the Mab from G10G5 stained oocytes of pigs and hamsters but Mabs from C6H1, D3H4, G10F9 stained oocytes of pigs, humans, hamsters, rats and mice. Mabs from B11C8 and G10F9 strongly blocked boar sperm binding to porcine ZP but other Mabs produced only slight blocking. However, no Mabs could block sperm penetration during in vitro fertilization (IVF) of hamster oocytes. When a goat antibody (IgG) to mouse serum gamma-globulin was applied after each Mab as a second antibody, only Mab from G10G5 impaired IVF of hamster oocytes.

Localization of human seminal plasma No. 7 antigen (Ferrisplan) in accessory glands of male genital tract and spermatozoa

The establishment of a hybridoma (1C4) producing sperm immobilizing monoclonal antibody to human seminal plasma No. 7 antigen (HSP No. 7 Ag.) and the isolation of the pure antigen by immunoaffinity chromatography bound monoclonal antibodies have been reported previously. In the present investigation, HSP No. 7 Ag. has been termed 'Ferrisplan' and its distribution in male genital organs, spermatozoa and body fluids has been studied. The amount of Ferrisplan in the body fluids was determined by radioimmunoassay. Large amounts were detected in seminal plasma and milk, trace amounts in saliva, and none in the serum and urine. The concentration of Ferrisplan was highest in the seminal plasma of azoospermic patients and gradually decreased from oligospermia to normospermia. Using an immunofluorescent method with anti-Ferrisplan monoclonal antibody, strong staining was observed on the epithelial layers of human seminal vesicles, no staining on testes and bright staining on the post-nuclear cap and mid-piece segment of spermatozoa. These results indicate that Ferrisplan is excreted mainly from the seminal vesicle and adheres to the post-nuclear cap and mid-piece of the spermatozoa as a sperm-coating antigen.

Purification of human seminal plasma no. 7 antigen by immunoaffinity chromatography on bound monoclonal antibody

Human seminal plasma (HSP) No. 7 antigen was purified by immunoaffinity chromatography on bound 1C4 monoclonal antibody (Moab) (Shigeta et al., 1980b). The pooled HSP protein was applied to a CNBr-activated Sepharose 4B column of bound 1C4 Moab gamma globulin and the antibody bound fraction (fr) eluted was further purified by rechromatography in the same way. The purified antigen in the antibody bound fr obtained by rechromatography gave a single band on SDS-PAGE in a position corresponding to a molecular weight of 15,000 daltons. This preparation was 196.2 times more effective than the original HSP protein in neutralizing the sperm immobilizing activity of 1C4 Moab. The purified HSP No. 7 antigen contained iron, but was different from lactoferrin and transferrin. It did not show any enzymatic activities, such as those of acid phosphatase, LDH or trypsin inhibitor, and shared antigenicity with human milk protein. It was present in seminal plasma as a molecule with a higher molecular weight but seemed to be cleaved to a monomer of 15,000 daltons during purification procedures. This antigen is present on spermatozoa as sperm-coating antigen and the corresponding antibody can immobilize spermatozoa with complement.

[Studies of fertilizing capacity of spermatozoa from infertile men with oligozoospermia. AIH by washed and concentrated spermatozoa and in vitro fertilizing capacity to zona free hamster eggs (author's transl)]

The fertilizing abilities of spermatozoa from infertile men with oligozoospermia were evaluated by examining pregnancy rates after AIH using washed and concentrated spermatozoa, and also by in vitro fertilizing rates to zona free hamster eggs. The spermatozoa from ten oligozoospermic men with less than 20 x 10(6)/ml of sperm counts were used in the experiments. After the procedures of washing and concentrating spermatozoa from oligozoospermic men, the sperm concentration was increased from two to six times and the sperm motility was also increased up to two times. However none of the patients' wives conceived after several AIHs with washed and concentrated spermatozoa. When the in vitro fertilization of zona free hamster eggs by the spermatozoa was used, the fertilization rates were null in case of 7 oligozoospermic patients, and 5, 10 and 33.3% in case of another 3 oligozoospermic patients respectively in contrast with 73.3% in use of spermatozoa from control fertile men. The fertilizing abilities of spermatozoa from husbands of 4 sterile couples with an unknown cause were examined by in vitro fertilization test and 7.1, 37.5, 50.0 and 55.6% fertilization rates were obtained. Among these men, the spermatozoa from one man indicated a very low fertilization rate without any other pathological findings. This suggests that the impairment of fertilizing ability of spermatozoa might be present in the case of sterile men with an unknown cause.

Effect of purified zona antibody on fertilization in the mouse

Bivalent (IgG) rabbit anti-mouse zona pellucida antibody completely inhibited fertilization in the mouse. Univalent (Fab) zona antibody did not inhibit the fertilizability of eggs. However, the treatment or injection with anti-rabbit IgG serum inhibited the fertilization of eggs pretreated with antiserum Fab or eggs from females injected with antiserum Fab. It is concluded that the inhibition of fertilization by bivalent louse zona antibody depends on the possibility that the antisera are directed against the zona as a whole and not specifically against the receptors for the sperm.

[Comparative studies on doses of complement for detection of sperm immobilizing antibody in serum, cervical mucus and seminal plasma (author's transl)]

In Isojima's sperm immobilization test, the complement is one of the most important factors which influence on sensitivity of the test. Previously we reported that more than 10 CH50 of guinea pig serum complement was necessary in the reaction to obtain the best result for measuring the sperm immobilizing antibody in the serum. This time, the influences of various test specimens on complement activities for the sperm immobilization test were studied and the necessary amounts of complement to detect the sperm immobilizing antibody in serum, cervical mucus and seminal plasma were compared. In the sperm immobilization test, the following results were obtained: 1. The amount of complement (guinea pig serum) added was 11.9 CH50, and after 60 minutes incubation at 32 degrees C in veronal buffer (VB2+), 2.0 +/- 0.3 (M +/- SD) of CH50 was consumed. 2. When human serum, cervical mucus and seminal plasma were added to the reaction as specimens, the complement consumptions (M +/- SD) were more 0.2 +/- 0.3 CH50, 0.2 +/- 0.2 CH50 and 3.3 +/- 0.8 CH50 than that of VB2+ buffer respectively. 3. When the washed human spermatozoa were added, the consumed amounts of complement (M +/- SD) were dose dependent; 3.5 +/- 0.7 CH50 for 100 X 10(4) spermatozoa, 7.3 +/- 0.3 CH50 for 200 X 10(4) spermatozoa and 15.7 +/- 2.2 CH50 for 400 X 10(4) spermatozoa. 4. In our sperm immobilization test, the net consumptions of complement (M +/- SD) were 5.0 +/- 0.7 CH50 for specimen of serum, 4.9 +/- 0.8 CH50 for specimen of cervical mucus and 11.1 +/- 1.2 CH50 for specimen of seminal plasma. 5. Complement doses necessary to obtain the most sensitive sperm immobilization tests were 10 CH50 for both serum and cervical mucus specimens, and 15 CH50 for seminal plasma specimen.

[Role of complement for the sensitivity of sperm immobilization test (author's transl)]

For detecting the sperm immobilizing antibody in the sera of infertile women with unknown cause, Isojima's sperm immobilization test was widely used, but there was great difference on the percentage of positive results among several laboratories. For analysis of factors influencing the sensitivity of the test, source and amount of complement were studied, and the following results were obtained. 1. Guinea pig serum which contained more than 200 CH50 as hemolytic titer was best for this test. 2. Rat and rabbit sera which contained much lower CH50 than guinea pig indicated relatively good sensitivity for the test. 3. Human serum which contained 34.9 CH50/ml and mouse serum which contained less than 5 CH50/ml, both could not work on sperm immobilization test. The human serum (AB) which was concentrated to the level of guinea pigs serum as CH50 did not work well on sperm immobilization test as guinea pig serum. 4. When the complement from same source was used, the positive correlation between CH50 (hemolytic titer) and 50% sperm immobilization titer (SI50) was present, but if the complement source was different, there was no correlation between CH50 and SI50. 5. It was proved that more than 10 CH50 of guinea pig serum was necessary for sperm immobilization test to obtain the most sensitive results.

Sperm-immobilizing monoclonal antibody to human seminal plasma antigens

Rat spleen cells immunized to human azoospermic semen (a mixture of seminal plasma components) and mouse myeloma cells (P3/X63 Ag8U1; P3U1) (Marguilies et al., 1976) were successfully fused with polyethylene glycol (PEG 1500) and 19 of 89 fused cell cultures were found to produce sperm-immobilizing antibody. The cells that produced antibody indicating the highest sperm-immobilizing activity were distributed into wells for further recloning and 10 clones producing sperm-immobilizing antibody were established. The clone (1C4) producing the highest antibody titre was found to produce a large amount of IgG in culture supernatants and to contain a mixture of rat and mouse chromosomes. It was proved by immunodiffusion test that the monoclonal antibody was produced to the human seminal plasma antigen No. 7 which is common to human milk protein. Using this hybridoma which produced a large amount of monoclonal sperm-immobilizing antibody, a new method could be developed for purifying human seminal plasma antigen by immunoaffinity chromatography with bound antibody from the hybridoma.