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Biomedical subjects

R K Naz

Publications and source records attributed to R K Naz.

At least 55 records · Page 3Linked to original sources
PubMed1994

Expression of scatter factor/hepatocyte growth factor is regionally correlated with the initiation of sperm motility in murine male genital tract: is scatter factor/hepatocyte growth factor involved in initiation of sperm motility?

Based upon findings that the scatter factor/hepatocyte growth factor (SF/HGF) has strong mitogenic and motogenic properties, and that the sperm cell acquires its fertilizing capacity and motility in the distal parts of mammalian epididymis, the present study was conducted to investigate the role of SF/HGF in initiation of sperm cell motility. This was investigated by determining the expression of SF/HGF in various regions of the murine male genital tract by scatter and cell tracking assays using MDCK epithelial cells, Western blot procedure, and the immunohistochemical procedure using paraffin sections of various regions of the male genital tract. The findings from all these assays indicate that SF/HGF is differentially expressed in various parts of the male genital tract with slight or no expression in the testes, caput epididymis, and vas deferens, and with the highest expression in cauda and corpus (distal) epididymis followed by expression in the corpus (proximal) epididymis. This region-specific SF/HGF expression pattern coincides with the pattern of acquiring the fertilizing capacity and motility by the sperm cell during its transit through the male genital tract. However, wherever SF/HGF was expressed in the male genital tract, its molecular weight was slightly higher (Mr, 82 kD), compared to the SF/HGF expressed in various other somatic tissues (Mr, 78 kD), indicating that the genital tract SF/HGF may be a different molecular species that shares some immunoreactive epitopes with the somatic cell SF/HGF. Incubation of immotile sperm from caput epididymis with the purified human placental SF/HGF of 78 kD initiated motility in 5-15% of sperm population. These results strongly suggest that the SF/HGF-like activity is expressed in the male genital tract in a region-specific manner, and this activity may have a role in initiation of sperm motility acquired during its transit through the epididymis in mammals.

Animals↗
PubMed1994

Molecular identities of human sperm proteins that bind human zona pellucida: nature of sperm-zona interaction, tyrosine kinase activity, and involvement of FA-1.

The present study was conducted to investigate the molecular identities, nature of interaction, and tyrosine phosphorylation activity of the sperm-zona pellucida binding proteins in humans. Sperm proteins belonging to four major molecular regions, namely 95, 63, 51, and 14-18 kDa, reacted with zona pellucida proteins in the Western blot and immunoprecipitation procedures. In these procedures, zona pellucida protein that reacted strongest with the sperm proteins belonged to the molecular region of 55 kDa (ZP3), besides weakly reacting proteins in the 110-kDa (ZP1/ZP2) and 14-18-kDa molecular regions. The major forces involved in the sperm-zona protein interactions were of hydrophobic and ionic in nature. Three (95, 51, and 14-18 kDa) of the four molecular regions of sperm proteins that bound to the zona pellucida proteins also seem to involve o-phospho-L-tyrosine residues in their interaction, and these proteins demonstrated the presence of phosphotyrosine residues, and the 51-kDa protein also showed autophosphorylating activity in the in vitro kinase assay. The sperm binding zona protein of 55 kDa also demonstrated autophosphorylating activity. Using specific monoclonal antibody to the well characterized sperm-specific glycoprotein, designated FA-1, and the competitive inhibition in the immunoprecipitation procedure, it was found that the 51 kDa protein is indeed FA-1 antigen. Besides elucidating the molecular nature of the sperm-zona interaction, these antigens will find application in the development of a multivalent contraceptive vaccine, and may also help in specific diagnosis and treatment of infertility mediated through defective gamete (sperm or oocyte) function.

Antigens↗
PubMed1994

Expression and role of c-myc protooncogene in murine preimplantation embryonic development.

PURPOSE: The present study was conducted to investigate the expression and possible role of the c-myc protooncogene in preimplantation embryos by using reverse-transcriptase/polymerase chain reaction (RT-PCR) technique and microinjection of synthetic antisense c-myc oligonucleotide probe, respectively. Total RNA was extracted from oocytes and two cell-, four cell-, early morula-, late morula-, early blastocyst-, and late blastocyst-stage embryos, and cDNA was constructed using MMLV reverse transcriptase. Sense primer (P1) and antisense primer (P2) used were based on the c-myc gene sequence bp 1609-1629 and bp 3279-3299, respectively, that span a 1.37-kb intron. PCR-amplified products of cDNA from oocyte-, two cell-, four cell-, early and late morula-, and blastocyst-stage embryos demonstrated the expected 313-bp product in Southern blot hybridization using a c-myc specific DNA probe, with an indication of lower levels in oocytes and early morulae. RESULTS: Cytoplasmic injection of the antisense c-myc oligonucleotide probe (P2) and not the sense probe (P1) into pronuclear-stage zygotes caused a significant (P = 0.02 to 0.0001) inhibition of development to blastocysts in a concentration-dependent manner, with a maximal inhibition at the first cleavage of zygotes to two cell-stage embryos. There was no effect on the P2 antisense injection on pronucleus formation. CONCLUSION: These results indicate that the c-myc protooncogene is expressed in preimplantation embryos and may have an essential role in normal embryogenesis in mice.

Animals↗
PubMed1994

Antibodies to sperm-specific human FA-1 inhibit in vitro fertilization in rhesus monkeys: development of a simian model for testing of anti-FA-1 contraceptive vaccine.

The feasibility of using the rhesus monkey as a non-human primate model for testing the efficacy of a contraceptive vaccine based on FA-1 antigen was evaluated. Affinity-purified anti-FA-1 polyclonal antibodies (Fab' fragments) and anti-FA-1 monoclonal antibody were used as probes in these studies. Anti-FA-1 antibodies (polyclonal Fab' as well as monoclonal IgG) predominantly reacted with the postacrosomal, mid-piece and tail regions of rhesus monkey sperm, as with human sperm, by an indirect immunofluorescence technique (IFT). These antibodies also specifically recognized a single protein band of 51 +/- 2 kDa, corresponding to the dimeric form of FA-1 antigen, on a Western blot of lithium diiodosalicylate (LIS)-solubilized monkey sperm. Anti-FA-1 antibodies, when present in the insemination mixture, inhibited the in vitro fertilization (IVF) of monkey oocytes. These results indicate that FA-1 antigen in rhesus monkey sperm is similar in subcellular localization, molecular identity and function to that in human sperm, and that the rhesus monkey represents a permissible non-human primate model in which the efficacy of a contraceptive vaccine based on FA-1 antigen can be tested.

Animals↗
PubMed1994

Antisperm antibodies: origin, regulation, and sperm reactivity in human infertility.

OBJECTIVE: To follow-up and expand discussion on the action mechanisms of antisperm antibodies in human infertility, the etiology and control of antisperm antibody induction, sperm antigens involved in immunoinfertility, and strategies for therapy. DESIGN: A review of the recent literature with an emphasis on female immunoinfertility. RESULTS: The role of antisperm antibodies in clinical infertility continues to be defined. Through assisted reproductive technologies, antisperm antibodies were shown to exert detrimental effects on different prefertilization and possibly postfertilization events. The female reproductive tract is part of the common mucosal immune system and is able to mount effective immune responses against infectious agents, foreign antigens, and, occasionally, sperm cells. Sperm membranes and constituents contain numerous antigenic components foreign to the human body, and yet antisperm antibodies become problematic in few women exposed to semen. Semen and sperm cells contain immunosuppressive factors capable of inhibiting different immune cells. Fertile women apparently produce antisperm antibodies but also possess neutralizing serum anti-idiotypic antibodies that are lacking in virgin and immunoinfertile women. CONCLUSIONS: Antisperm antibodies can affect adversely human fertility but normally may be controlled by anti-idiotypic antibodies, which along with immunosuppressor factors in semen prevent their induction to a significant degree. This balance between detrimental and "beneficial" immune response to sperm may be shifted toward an antisperm antibody response by stimulatory factors such as infection. Therapies may be devised to stimulate the anti-idiotypic antibody system, to induce immune tolerance to sperm antigens, and to use antigens to adsorb antisperm antibodies from spermatozoa.

Antibodies↗
PubMed1994

Monoclonal antibody to human fertilization antigen-1 (FA-1) inhibits bovine fertilization in vitro: application in immunocontraception.

A monoclonal antibody (mAb) to the human sperm plasma membrane protein, fertilization antigen-1 (FA-1), was tested for its reactivity with bovine spermatozoa and its effects on bovine fertilization in vitro. Western blot analysis revealed that the FA-1 mAb reacted with proteins of similar molecular mass (53 +/- 2 kDa) in human and bovine sodium deoxycholate (DOC)-solubilized sperm extracts. Indirect immunofluorescence, using epifluorescence microscopy and laser scanning confocal microscopy, revealed that the FA-1 antigen is present in the post-acrosomal region of bovine spermatozoa, which is similar to human FA-1 localization. In bovine in vitro fertilization (IVF) trials, using oocytes obtained from slaughterhouse ovaries, addition of 20, 40, or 80 micrograms/ml of FA-1 mAb to the IVF medium resulted in a linear decrease in the fertilization rate from 86.3% in the controls to 54.6%, 21.6%, and 1.8% in the respective experimental groups (p < 0.01). There was no inhibitory effect (p > 0.10) of the FA-1 mAb on percent sperm motility or other motility characteristics tested, suggesting that human FA-1 mAb inhibits bovine sperm cell function at some point after capacitation. In conclusion, the evolutionarily conserved antigen FA-1 has a molecular identity in bovine sperm similar to that in human sperm, and mAb to human sperm FA-1 inhibits fertilization of bovine oocytes. These results indicate that FA-1 is a promising candidate for the development of a contraceptive vaccine. The research also suggests that bovine species could be used as a model for investigating the use of FA-1 as an immunovaccine in ruminants.

Animals↗
PubMed1994

Protein phosphorylation pattern and role of products of c-erbB-1 and c-abl proto-oncogenes in murine preimplantation embryonic development.

PROBLEM: To investigate the protein phosphorylation pattern and role of products of c-erbB-1 and c-abl proto-oncogenes with known tyrosine kinase activity in preimplantation embryonic development in mice. METHOD: The protein phosphorylation pattern was studied by in vitro 32P metabolic labeling of murine ova/embryos as well as by in vitro kinase assay performed directly on various ova/embryos extracts. The role of products of c-erbB-1 (170 kDa, receptor for epidermal growth factor [EGF]) and c-abl proto-oncogenes (150 kDa) was examined by in vitro culturing murine embryos in the presence of monoclonal antibodies to respective protein products and by co-culturing with EGF, the ligand for EGF receptor (EGF-R). RESULTS: In vitro metabolic labeling of murine ova/embryos showed 32P incorporation into at least two protein bands of murine ova (M(r) 81 and 36 kDa), six protein bands of two-cell (M(r) 81, 36; and 97, 52, 22 and 19 kDa, respectively), six protein bands of morula (M(r) 81, 36; 97, 22, and 19; and 33 kDa, respectively), and eight protein bands of blastocyst (81, 36; 97, 22, 19; and 115, 58, and 15 kDa, respectively), stage embryos; there were some specific bands in each stage. Prolonged labeling from 2 to 4 h not only resulted in a relative increase in 32P incorporation into these proteins but also revealed additional bands in morula (M(r) 133 and 115 kD) and blastocyst (M(r) 49, 33, and 31 kD) stage embryos. In vitro kinase assays performed directly on various ova/embryos extracts revealed at least three phosphoproteins (M(r) 58, 36 and 33, respectively) that were common to ova, two-cell, morula, and early/late blastocyst stage embryos. Additionally, three protein bands each in murine ova and two-cell embryos (M(r) 108, 81, 73 kDa, respectively), and four protein bands of late blastocyst (M(r) 108, 73; 133 and 18 kDa, respectively) stage embryos were also revealed. Culture of two-cell embryos in the presence of EGF, the ligand for EGF-receptor, resulted in a concentration dependent increase (P < .001) in the number of cells per blastocyst. Monoclonal antibody to c-erbB-1 170 kDa protein (receptor for EGF) did not affect development of in vitro cultured murine embryos from two-cell to morula, but significantly (P < .001) inhibited the in vitro development of morula to late blastocyst stage. Monoclonal antibody to c-abl protein inhibited the development of murine embryos from two-cell to morula (P < .017), as well as, from morula to late blastocyst stage (P < .002 to .01). CONCLUSIONS: These results suggest that the stage-specific protein phosphorylation pattern and specific products of c-erB-1 and c-abl proto-oncogenes may have a role in preimplantation embryonic development in mice.

Animals↗
PubMed1993

Presence and possible role of c-ras and nuclear (c-fos and c-jun) proto-oncogene products in preimplantation embryonic development in mice.

The presence and possible role of products of nuclear (c-fos and c-jun) and c-ras proto-oncogenes were investigated in preimplantation embryonic development in mice. Polyclonal antibodies to c-fos or c-jun proto-oncogene products did not affect development of in vitro-cultured embryos from two-cell to morula or from morula to late blastocyst stages. However, v-H-ras monoclonal antibody (mAb) to c-ras protein (p21), although it did not inhibit the development of in vitro-cultured embryos from two-cell to morula stages, it significantly (P < .001-.005) inhibited the development of morula to late blastocyst stages in a dose-dependent manner. The effects of v-H-ras mAb were specific, since immunoabsorption with synthetic ras peptide completely blocked inhibitory effects of v-H-ras mAb. Neither c-fos nor c-jun antibodies reacted with specific proteins corresponding to c-fos (62 kDa) and c-jun (39 kDa) products on the Western blots of various murine ova/embryos extracts. However, the c-fos and c-jun antibodies reacted with 62 and 39 kDa protein bands, respectively, on the blot of NIH 3T3 cells extract. The v-H-ras mAb specifically identified 21 +/- 3 kDa protein corresponding to c-ras p21 on the blots of early as well as late blastocyst extracts. The rat control ascites IgG1 did not react with any protein band on the blots of various ova/embryo extracts. The reactions of v-H-ras mAb on the Western blots of blastocyst extracts were specific, since immunoabsorbed antibody was unable to react with any specific band on blots of early or late blastocyst extract. These results were further confirmed by immunoprecipitation procedure utilizing v-H-ras mAb. Again, the v-H-ras mAb immunoprecipitated a 21 kDa band from early as well as late blastocyst extracts. The rat control ascites IgG1 did not react with any band corresponding to p21 in the immunoprecipitation procedure. These results suggest that the specific products of nuclear proto-oncogenes, the c-fos and c-jun, are not detected in murine ova and preimplantation embryos, and the respective antibodies do not inhibit embryogenesis, indicating that they may not play a major role in early embryonic development. On the other hand, the product of c-ras proto-oncogene is specifically expressed in the blastocyst-stage embryos and may have a possible role in preimplantation embryonic development in mice.

3T3 Cells↗
PubMed1993

Immunoglobulin (Ig) G, IgA, and IgA subclass antibodies against fertilization antigen-1 in cervical secretions and sera of women of infertile couples.

OBJECTIVES: To assess the occurrence of immunoglobulin (Ig) G, IgA, and IgA subclass antibodies against human sperm fertilization antigen-1 (FA-1) in cervical mucus (CM) and serum of women of infertile couples. DESIGN: Enzyme-linked immunosorbent assay methodology was used to detect anti-FA-1 antibodies. Antisperm antibodies were detected by agglutinating, immobilizing, and indirect immunobead (IB) methods. Control samples for the ELISA were from 10 women negative in the antisperm antibody assays. PARTICIPANTS: Samples were from women of 32 infertile couples undergoing antisperm antibody analysis. RESULTS: One of 10 control CM samples was slightly positive for IgG anti-FA-1 and none for IgA. Of the 22 CM samples from antisperm antibody-positive women, 9 were positive for IgG antibodies, 9 for IgA, 7 for IgA1, and 6 for IgA2. Cervical mucus samples from eight women were positive for both IgA and IgG antibodies. Assay of 19 serum samples, including 8 controls, by ELISA, indicated 9 of 11 from antisperm antibody-positive women and none from controls were positive for IgA and IgG (7 of 9 identical women). In addition, of the nine IgA-positive sera, seven were of the A1 subclass and five were of the A2 subclass. Positive IB assays occurred more frequently in CM and serum samples positive for anti-FA-1 antibodies than in negative samples. CONCLUSION: The results suggest that cervical secretions and sera of antisperm antibody-positive women contain IgA and IgG antibodies against sperm antigen FA-1 that may be involved in antifertility effects.

Antibodies↗
PubMed1993

Involvement of cyclins and cdc2 serine/threonine protein kinase in human sperm cell function.

The presence and roles of mitotic cyclins (cyclin A and cyclin B1), and cdc2 and related (having an N-terminal PSTAIRE conserved sequence) serine/threonine protein kinases were investigated by use of specific antibodies. The cyclin A and cyclin B1 antibodies reacted specifically with the acrosomal regions of human sperm cells in the indirect immunofluorescence technique (IFT) and recognized the specific band of p60 (cyclin A) and p62 (cyclin B1) on the Western blot of sodium deoxycholate (DOC)-solubilized noncapacitated human sperm preparation. Both antibodies reacted more strongly with the specific cell region/band of capacitated sperm than with that of noncapacitated sperm. The cdc2 and PSTAIRE antibodies also reacted predominantly with the acrosomal regions of human sperm cells in IFT and recognized the specific band of 34 kDa corresponding to p34 cdc2 protein on the Western blot of DOC-solubilized noncapacitated human sperm preparation. Again, both antibodies reacted more strongly with the specific cell region/band of capacitated sperm than with that of noncapacitated sperm. The cyclin A antibodies (but not the cyclin B1 antibodies) and cdc2 antibodies as well as the PSTAIRE antibodies significantly (p = 0.02 to p < 0.001) increased (rather than decreased) the human sperm penetration rates of zona-free hamster ova; the cyclin A and cdc2 antibodies showed the strongest enhancing effects. These three antibodies significantly increased the acrosome reaction and release of acrosin activity from the sperm cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗
PubMed1993

Characterization of a sperm-specific monoclonal antibody and isolation of 95-kilodalton fertilization antigen-2 from human sperm.

Monoclonal antibodies (mAbs) were raised in mice against human sperm. Of the eight hybridomas secreting mAbs that react with human sperm, one, the Vic-1 antibody, was selected for detailed analysis because of its high degree of tissue specificity. The Vic-1 antibody was of the IgG1 subclass and demonstrated binding predominantly with the acrosomal regions of viable but not methanol-fixed noncapacitated and capacitated human sperm cells. It also reacted with the acrosomal and mid-piece regions of viable capacitated as well as noncapacitated murine sperm, but not with methanol-fixed murine sperm. The Vic-1 antibody was germ-cell specific as it did not react with any human somatic cell, tissue, or secretion examined including seminal plasma. The Vic-1 antibody significantly (p = 0.0006) inhibited human sperm penetration of zona-free hamster oocytes in a concentration-dependent manner; at 15 g% concentration it almost completely blocked sperm penetration. The antibody significantly reduced the acrosome reaction and the release of acrosin activity in human sperm cells. There was no effect of the Vic-1 antibody on percentage of motile sperm, although it significantly affected motility characteristics such as linearity, amplitude of lateral head displacement, and beat frequency; motility parameters involved in the hyperactivation phenomenon related to capacitation and the acrosome reaction. The Vic-1 antibody recognized a predominant antigen of 95 kDa, designated fertilization antigen-2 (FA-2), in Western blot and immunoprecipitation procedures using human sperm preparations. The FA-2 antigen was isolated from human sperm preparations by using an immunoaffinity column containing the Vic-1 antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗
PubMed1993

Antiidiotypic antibodies to sperm in sera of fertile women that neutralize antisperm antibodies.

The presence of antiidiotypic antibodies (ab-2) to sperm was investigated in the sera of fertile, infertile, and virgin women using sperm-specific anti-FA-1 monoclonal antibody Fab'.ab-2 were detected in 71% (17/24) of sera from fertile women and in none (0/12) of the sera from virgin females by the enzyme-linked immunosorbent assay, Western blot procedure, and immunoprecipitation procedure. Sera from infertile women that had antisperm antibodies showed a minimal presence of ab-2, with only three sera (13%, 3/23) demonstrating the presence of low levels of ab-2. The ab-2 present in fertile women were capable of neutralizing the fertilization-inhibitory activity of anti-FA-1 antibody in a concentration-dependent manner in a human sperm penetration assay (SPA) of zona-free hamster oocytes. ab-2 were also capable of inhibiting the binding of antisperm antibodies to the sperm surface as determined by the immunobead binding technique. This is the first report demonstrating the presence of ab-2 in the sera of fertile women that are capable of neutralizing antisperm antibodies present in sera of infertile women. These findings suggest that the inability to detect antisperm antibody activity in the sera of fertile women may be due to higher levels of ab-2 present in these sera than levels found in sera of infertile women, although both groups may be producing antisperm antibody response after sexual exposure to sperm.

Adult↗
PubMed1993

c-MYC mRNA is present in human sperm cells.

Stage-specific expression of proto-oncogenes, including c-myc, has been demonstrated during spermatogenesis in testis. Some of these proto-oncogenes are expressed postmeiotically, especially in the round spermatid stage. Recently, we demonstrated the presence of c-myc protein in mature ejaculated sperm cells with a possible role in sperm cell function. Since the half-life of c-myc protein has been shown to be short, we suspected the presence of c-myc mRNA in human sperm cells. In the present study, the presence of the c-myc mRNA transcript in human sperm cells was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and in situ hybridization. Total RNA, 5-10 micrograms, was extracted from 0.2-0.5 ml of pelleted human sperm cells by NP-40 lysis procedure, and was used to construct cDNA with pd(N)6 random primer and Moloney Murine Leukemia Virus (MMLV) reverse transcriptase. The PCR with sperm cDNA and primers #P1 and #P2, both from exon 3, resulted in amplification of the expected 322 bp product. Primers #P3 and #P4, which are located in exon 2 and exon 3, respectively, and are 1.37 kb apart, gave the expected PCR amplified 313 bp product ruling out the possibility of DNA contamination. The presence of c-myc mRNA in human sperm cells was further confirmed by in situ hybridization using a digoxigenin labelled DNA probe, containing exon 2 of the c-myc gene sequence. The c-myc specific DNA probe reacted with the postacrosomal mid-piece and tail regions of both noncapacitated as well as capacitated methanol-fixed sperm cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1992

Human cleavage signal-1 protein; cDNA cloning, transcription and immunological analysis.

The cleavage signal-1 protein (CS-1), a doublet antigen comprised of approx. 14-kDa and 18-kDa proteins has been shown to be present on the surface of sperm of various mammalian species including humans. Polyclonal antibodies to CS-1 inhibit the early cleavage of fertilized eggs without apparently affecting sperm penetration and pronuclear formation. We report here the cloning of the human CS-1 cDNA and its expression in vitro to obtain the recombinant protein (reCS-1) molecule. The CS-1 cDNA clone was isolated by immunological screening of a human testis lambda gt11 cDNA library with mono-specific polyclonal antibody against CS-1. The cDNA is 1828 bp long; the start codon assigned to the first ATG (bp 98-100) encodes a protein with 249 amino acid residues terminating at TAA (bp 845-847). The cDNA isolated has a 97-bp 5' and a 984-bp 3' untranslated region. The potential polyadenylation signal (5'-AATAAA) is at bp 1803-1808. An extensive computer search of the GenBank database did not indicate any extensive homology with any known sequence, indicating that CS-1 is a unique protein. The CS-1 cDNA was cloned in the transcription vector, pGEM-11Zf, to obtain high-level in vitro transcription by SP6 and T7 RNA polymerase. The transcribed CS-1 RNA was translated in a rabbit reticulocyte in vitro translation system and produced a 33-kDa reCS-1 protein, as assessed by migration in a SDS-polyacrylamide gel.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Presence of expression products of c-erbB-1 and c-erbB-2/HER2 genes on mammalian sperm cell, and effects of their regulation on fertilization.

The present study was conducted to investigate the presence of expression products of c-erbB-1 and c-erbB-2/HER2 genes on mammalian sperm cell, and study the effects of their antibodies on fertilization. The mature sperm cells from various mammalian species (human, mouse, rabbit and rat) were found to have EGF-receptors but not the p185HER2 molecules by indirect immunofluorescence technique (IFT) and Western blot procedure. Though the EGF-receptors present on sperm cells were functionally active and responded to ligand binding, their activation by EGF or blocking by antibodies did not affect the sperm cells in acquiring their fertilization potential. These results indicate that the products of c-erbB-1 and c-erbB-2/HER2 genes, though they have been shown to have tyrosine kinase enzyme activity, do not seem to play a major role in the development of the fertilizing capacity of sperm cells.

Amino Acid Sequence↗
PubMed1992

Effects of antibodies to sperm surface fertilization antigen-1 on human sperm-zona pellucida interaction.

OBJECTIVE: To investigate the effects of antibodies to well-defined sperm surface antigens (the fertilization antigen [FA-1] and germ-cell antigen [GA-1]) and nuclear antigen (protamine) on human sperm-zona interaction. DESIGN: Number of total and acrosome-reacted human sperm bound to the human zona pellucida and the sperm movement characteristics assessed by computer-aided sperm analysis were evaluated after incubation of sperm with the antibodies. SETTING: Academic research environment approved by the Institute Review Board. PATIENTS: Human oocytes were obtained from ovaries removed at surgery. Semen from fertile donors was used in all assays. INTERVENTIONS: Human oocytes were stored in salt solution at -80 degrees C until used. Spermatozoa were treated with the antibodies to various sperm antigens. MAIN OUTCOME MEASURES: Total and acrosome-reacted sperm bound to zona pellucida and sperm movement characteristics were evaluated after 3 to 5 hours of incubation of the antibodies with human sperm. RESULTS: Anti-FA-1 antibodies significantly reduced human sperm fusion with zona-free hamster oocytes and sperm binding to the human zona pellucida but did not affect binding of acrosome-reacted sperm and sperm movement characteristics. Anti-GA-1 and antiprotamine antibodies did not affect sperm-oocyte interaction, acrosomal reaction, or sperm motility. CONCLUSIONS: Antibodies to FA-1 but not to GA-1 and protamine inhibit human sperm-zona interaction.

Acrosome↗
PubMed1992

The fertilization antigen-1 does not have proteolytic/acrosin activity, but its monoclonal antibody inhibits sperm capacitation and acrosome reaction.

OBJECTIVE: To determine if human sperm surface fertilization antigen exhibits proteolytic or acrosin activity and to investigate the mechanism(s) whereby monoclonal antibody (mAb) to fertilization antigen inhibits human sperm penetration of zona-free hamster ova. DESIGN: Proteolytic and acrosin activities of human fertilization antigen were determined. Acrosomal status, acrosin activity, and motion characteristics were evaluated after incubation of human sperm with immunoaffinity-purified mAb to fertilization antigen. SETTING: Academic research environment. PARTICIPANTS: Fertile donors used as controls for infertile patients for fertility evaluation. INTERVENTIONS: Human spermatozoa were treated with mAb to fertilization antigen and induced to undergo acrosome reaction using calcium ionophore A23187. MAIN OUTCOME MEASURES: Proteolytic and acrosin activities of fertilization antigen. Sperm penetration assay, acrosomal status, and motion parameters. RESULTS: Fertilization antigen does not exhibit proteolytic or acrosin activity; however, its mAb completely blocks human sperm penetration of zona-free hamster ova. The mAb to fertilization antigen inhibits ionophore-induced acrosome reaction and blocks development of the hyperactivated state of human sperm cells. CONCLUSIONS: Monoclonal antibody to fertilization antigen blocks fertilization by inhibiting capacitation and acrosome reaction.

Acrosin↗