Biomedical subjects

R K Naz

Publications and source records attributed to R K Naz.

At least 109 records · Page 6Linked to original sources

PubMedDate not supplied

Antibodies to human sperm YLP12 peptide that is involved in egg binding inhibit human sperm capacitation/acrosome reaction.

Recently, the authors reported a novel dodecamer peptide sequence, designated as YLP12 on human sperm, that is involved in binding to zona pellucida (ZP) of human oocyte [10]. This unique sequence is present on the acrosomal region of the human sperm cell and is expressed only in human testis/ sperm. The aim of the present study was to examine whether YLP12 sequence is involved in capacitation/acrosome reaction. Swim-up sperm were capacitated with anti-YLP12 Fab' antibodies or control Fab's (40 and 85 microg/mL) and then the acrosome reaction was induced with calcium ionophore. An average of 64-73% sperm underwent acrosome reaction when they were capacitated in the presence of 40-85 microg/mL of bovine serum albumin or control Fab's. A significant (p < .01 to < .001) reduction (58-75%) in the percentage of acrosome-reacted sperm was observed when the sperm were capacitated in the presence of YLP12 Fab's. These data indicate that the YLP12 peptide sequence is involved in sperm capacitation / acrosome reaction, and may find clinical applications in the diagnosis and treatment of male infertility and immunocontraception.

Acrosome Reaction↗

PubMedDate not supplied

Monoclonal antibody against human sperm-specific YLP12 peptide sequence involved in oocyte binding.

The monoclonalantibody (mAb) against YLP12 peptide was raised and its immunobiological properties were examined. In the Western blot procedure, the YLP12 mAb recognized a specific protein band of approximately 50 +/- 5 kD in human sperm extract and approximately 72 +/- 5 kD in human testis extract. The myeloma Ig control did not recognize these specific protein bands. In the immunofluorescence studies, the YLP12 mAb, and not the myeloma Ig, predominantly reacted with the acrosome regions of methanol-fixed human sperm. In the acrosome reaction assay, the YLP12 mAb showed a significant (p < .001) and a concentration-dependent inhibition of acrosome reaction. The myeloma Ig did not affect the acrosome reaction. There was no apparent effect of antibodies on sperm motility. Thus, the monoclonal antibody, if humanized by genetic engineering technology, may provide a useful immunocontraceptive agent.

Acrosome Reaction↗

PubMedDate not supplied

Sperm surface protein profiles of fertile and infertile men: search for a diagnostic molecular marker.

The present study was conducted to examine whether there is any difference in the protein profiles of sperm membranes of fertile (n = 37) and infertile (n = 29) men. In the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) procedure, the sperm extracts of fertile and infertile men showed 12-16 major and 8-14 minor common protein bands in various molecular regions. However, there was an additional band of approximately 78 kD present in the sperm extracts of approximately 80% of infertile men that was absent in the sperm extracts of fertile men. In the remaining approximately 20% of the infertile men, it was of relatively weaker intensity. This band was present only in the sperm extracts and not in the seminal plasma, whether of fertile or infertile men, and was designated as the infertility-associated sperm protein (IASP). Antibodies to IASP specifically immunoprecipitated the approximately 78-kD protein from the sperm extracts of only infertile and not the fertile men. In the immunofluorescence technique, the anti-IASP antibodies reacted strongly with the head and/or midpiece regions of morphologically abnormal sperm and cross-reacted with a protein in the equatorial regions of morphologically normal sperm of fertile men. The IASP molecule and its antibodies may provide molecular tools to differentiate between the normal and abnormal sperm, and, thus, may be useful markers for the diagnosis of male-factor infertility.

Biomarkers↗

PubMedDate not supplied

Identification of insulin-like growth factor (IGF)-1 receptor in human sperm cell.

The present study was conducted to examine the presence of insulin-like growth factor- receptor (IGF-1R) in human sperm cell. The IGF-1R monoclonal antibody (MAb) specifically immunoprecipitated two protein bands of approximately 135 and approximately 220 kD, respectively, from the reduced human sperm extract. These bands correspond to the alpha-subunit and partially reduced IGF-1R molecule, respectively. The immunocytochemistry experiments indicated the presence of IGF-1R primarily in the equatorial regions, along with a weak binding in the acrosomal regions of human spermatozoa. These data indicate that the IGF-1 receptor is present in the human sperm cell. Since the IGF-1 receptor has tyrosine kinase activity and its ligand IGF-1 is present in the seminal plasma, the IGF-1 system (IGF-1R/IGF-1/IGF-binding protein) may be involved in the signal transduction pathway leading to sperm capacitation and acrosome exocytosis.

Acrosome↗

PubMedDate not supplied

Antisperm antibodies in human immunodeficiency virus infection: effects on fertilization and embryonic development.

Sera from human immunodeficiency virus (HIV)-infected males (n = 10) and females (n = 5) were analyzed for the presence of antisperm antibodies reacting against sperm-specific antigens. Of the HIV-positive males tested, sera of 40% were positive for human sperm extract (HSE), 70% for protamine, and 70% for fertilization antigen (FA-1) for at least one class of antibodies, compared to sera from HIV-negative males. Of the HIV-positive females tested, sera of 40% were positive for HSE, 30% for protamine, and 30% for FA-1 compared to sera from HIV-negative females. The majority of the sperm antigen-reactive antibodies belonged to the IgG class. The reactions observed with FA-1 were weaker than those with other antigens. Ninety percent of HIV-positive male sera and 80% of the HIV-negative female sera were found to contain immune complexes, 20% of which showed the presence of FA-1. HIV-positive male or female sera did not bind to any specific protein on the Western blot of HSE. The minimal amount of free anti-FA-1 antibodies present in sera did not bind to live sperm in the sperm immobilization technique, sperm agglutination technique, or immunobead binding technique and thus were incapable of affecting human sperm penetration of zona-free hamster ova (SPA). Nor did HIV-positive sera induce any apparent abnormality in the development of 2-cell embryos to blastocysts in vitro in murine bioassay. In conclusion, these results indicate that HIV-infected patients have sperm-specific antibodies in their sera that do not adversely affect SPA and murine embryo bioassay. There was a high incidence of immune complex formation after HIV infection. These data will provide the basis for exploring further the role of sperm antigens in altering the immunoregulatory mechanisms after HIV infection.

Adult↗

PubMedDate not supplied

Effects of human antisperm antibodies on development of preimplantation embryos.

The effects of antisperm antibodies (ASAs) present in sera of immunoinfertile patients and vasectomized men were investigated on preimplantation embryonic development in mice. Of the nine immunoinfertile sera tested, two were effective in inhibiting blastulation rates of in vitro cultured murine 2-cell embryos (p less than .05 to .002). Similarly, sera from two of the three vasectomized men were capable of affecting early embryonic development in mice (p less than .05 to .002). Specificities of the embryotoxic effects of ASAs were further confirmed by culturing embryos in the presence of affinity-purified monovalent Fab' antibodies isolated from these sera. Fab' antibodies from only one of the two immunoinfertile patients whose sera affected blastulation rates, and from one of the three vasectomized men were effective in influencing blastulation rates of in vitro cultured 2-cell murine embryos (p less than .05 to .001), mainly due to an arrest of development at 2 to 8-cell and morula stages. In the Western blot procedure, none of the immunoinfertile Fab' antibodies recognized any specific band on blots of extracts from murine ova or 2-cell embryos. However, all the immunoinfertile Fab', but not fertile control Fab', specifically recognized a protein band in the M(r) 25 +/- 2 kD region, on the Western blots of extract from murine blastocyst stage embryos. In addition, Fab' from one immunoinfertile serum, which inhibited embryonic development, reacted specifically with a protein band in the lower molecular range (approximate M(r) 12 kD) on Western blot involving exact from blastocysts. Fab' antibodies of sera from vasectomized men did not react with any specific protein band on blots of extracts from murine ova, 2-cell embryo, or blastocyst. These results suggest that ASAs from some immunoinfertile patients and vasectomized men, especially those reacting with 12-kD blastocyst protein, are capable of affecting preimplantation embryonic development in mice, and thus may contribute toward immunologically medicated infertility both at fertilization and postfertilization stages.

Adult↗

PubMedDate not supplied

Antigenic differences in human sperm samples related to various morphological abnormalities.

Sperm samples were collected from male partners of fertile and infertile couples having unexplained and male factor infertility and analyzed for morphological abnormalities. After a staining procedure, sperm samples of these infertile men showed a variety of abnormalities. The sperm samples were also studied for their binding with the Abs directed against protamine (the nuclear protein), fertilization antigen (FA-1, sperm surface antigen), and the lithium diiodosalicylate- (LIS-) solubilized sperm preparation, and the binding was correlated with the percentage of morphologically abnormal sperm in the sample. Abs used in the present study were raised in female rabbits and had high titers (ELISA titers, 1:4096 to 1:8196), and recognized no band (anti-protamine), one 49,000- +/- 2000-dalton band (anti-FA-1), and at least 8 bands of various molecular identities in the 14,000- to 92,000-dalton range (anti-LIS sperm) on the Western blot of LIS-solubilized human sperm. The affinity-purified Fab' antibodies were iodinated and used in a radioimmunobindingassay for testing their binding with the sperm cells. Anti-protamine Fab's showed minimal binding and the binding activity (cpm bound/10 x 10(6) sperm cells) did not correlate (head defect, r = .12; midpiece defect, r = .07; tail defect, r = .11) significantly with percentage of abnormal cells in the sample. The binding of the anti-FA-1 Fab's also did not show a significant correlation (head defect, r = .29; midpiece defect, r = .48; tail defect, r = .23), though a positive trend (p = .05) was observed with the midpiece defect. In contrast, the binding of anti-LIS sperm Fab's demonstrated a significant correlation with the percentage of abnormal sperm cells in the sample (head defect, r = .51, p = .04; midpiece defect, r = .80, p less than .0001; tail defect, r = .23, p = .039). With an increased percentage of abnormal sperm cells, especially those with midpiece defect, there was an increased binding of anti-LIS sperm Fab's. These results suggest that with an increase in percentage of abnormal sperm, there is a change in antigenicity of the sperm cells. An increase in structural abnormality may enhance antibody binding to an abnormal sperm cell, thus causing a further decrease in its fertilizing capacity.

Antigens↗

PubMedDate not supplied

Significance of antibodies against human sperm FA-1 antigen in immunoinfertility.

A fertilization antigen (FA-1) has been identified on human sperm cells that is involved in human fertilization. To better explain the participation of FA-1 in human infertility, the relationship of anti-FA-1 antibodies with the presence of general antisperm antibodies and with sperm function was examined in the sera of 30 men and women. None of the sera from fertile men and women (n = 10) reacted with FA-1. In contrast, 55% of the immunoinfertile sera (n = 20) that were positive for antisperm antibodies detected by OPTI-BEAD (immune-labeled microsphere) tested positive with FA-1 (p < .05). In these sera, penetration of hamster oocytes was reduced and was inversely related to monospecific anti-FA-1 absorbance values determined by an ELISA and with heterospecific general antisperm antibody binding to sperm in the OPTI-BEAD test (p < .05). Anti-FA-1 activity approached significance with antisperm antibody binding to the sperm head (p = .052). It is concluded that immunoinfertile sera have antibodies reacting with the FA-1 sperm antigen and their presence is significantly related to results of other functional tests, such as the SPA and the OPTI-BEAD test. The association of anti-FA-1 antibodies with antibody binding site (sperm head) may be relevant to the diagnosis and treatment of immunoinfertility.

Animals↗

PubMedDate not supplied

Sequence homology among sperm antigens involved in mammalian fertilization: search for a common epitope for immunocontraception.

Sequence homology was searched among the nine cDNAs/deduced amino acid sequences encoding for the eight fertilization-related sperm antigens: namely, lactate dehydrogenase (LDH-C4), galactosyltransferase (GT), SP-10, rabbit sperm autoantigen (RSA), guinea pig (g)PH-20, cleavage signal protein (CS-1), HSA-63, human (h)PH-20, and AgX-1, respectively. Most significant identity (> 50%) was found between HSA-63 and SP-10 (59.8%), and between gPH-20 and hPH-20 (61.1%); followed by identity between SP-10 and GT (34.7%); and then between AgX-1 and hPH-20 (39.4%). All others had identity < 25%. The significance of these sequence homologies among the sperm antigens in the development of an antisperm contraceptive vaccine is discussed.

Animals↗

PubMedDate not supplied

Enhanced levels of colony stimulating factor-1 (CSF-1) in sera and seminal plasma of antisperm antibody-positive infertile men.

This investigation was carried out to examine the levels of CSF-1 in sera and seminal plasma of fertile, immunoinfertile, and male factor-infertile men in order to study the role of CSF-1 in human infertility. Sera, sperm, and seminal plasma were analyzed for antisperm antibodies by the sperm immobilization technique, tray agglutination technique, and immunobead binding technique. Sperm motility and fertilizing capacity were analyzed by sperm motion analysis and sperm penetration assay, respectively. CSF-1 concentration was estimated by the competitive radioimmunoassay. CSF-1 was detected in sera of both fertile and immunoinfertile men (mean +/- SD; fertile men: 52.9 +/- 10.3 pg/mg protein; immunoinfertile: 58.2 +/- 19.5 pg/mg protein; p > .05). CSF-1 was also detected in the seminal plasma of fertile, immunoinfertile, and male factor-infertile men (mean +/- SD; normal fertile men: 1.7 +/- 3.5 ng/mg; immunoinfertile men: 10.9 +/- 15.6 ng/mg; male factor-infertile men: 0.85 +/- 0.25 ng/mg). The levels of CSF-1 were highest in the immunoinfertile men, followed by those in fertile and male factor-infertile men. The average level in immunoinfertile men was significantly different from the average level in fertile or male factor-infertile men (p < .0001). Interestingly, the concentrations of CSF-1 per milliliter of seminal plasma was in general approximately 5 times greater than those in serum. These findings indicate that elevated seminal plasma CSF-1 concentration is correlated with male infertility.

Adult↗

PubMedDate not supplied

Effects of synthetic thymosin-alpha 1 and its analogs on fertilizability of human sperm: search for a biologically active, stable epitope.

Thymosin-alpha 1 (T alpha 1) and six T alpha 1 analogs were synthesized to study structure-function relationships and to search for the biologically active and stable epitope(s) that would have clinical application in the treatment of male infertility. Four of these analogs were prepared by modification/substitution of N- and C-terminal amino acids of T alpha 1 peptide, and the other two analogs were fragments having only N-16 amino acids (N-terminal) or C-14 amino acids (C-terminal), respectively, of the T alpha 1 peptide. T alpha 1 and these six analogs were tested for their effects on human sperm penetration rates in the sperm penetration assay (SPA). T alpha 1 significantly (p < .0001) increased the penetration rates in SPA, with the strongest enhancing effect at 0.5 microgram/100 microL concentration. Of the six analogs tested only two, T alpha 1-Gly-NH2 and T alpha 1-C14, retained the enhancing effects in SPA. None of the analogs decreased the penetration rates or affected sperm motility compared to control. The enhancing activity resides primarily in an epitope, the C-terminal 14 amino acids of T alpha 1. However, for maximal effect both N- and C-terminal amino acids (serine and asparagine, respectively) have to be intact and unmodified. The T alpha 1-Gly-NH2 analog that had its C-terminal protected was as potent as the intact T alpha 1 peptide. T alpha 1 and this analog may have clinical applications in treatment of male-factor-mediated infertility.

Adjuvants, Immunologic↗

PubMedDate not supplied

Treatment with thymosin alpha-1 increases fertilizing capacity of sperm of infertile men: a multicenter trial.

Thymosin alpha-1 (T alpha 1) significantly enhances the fertilizability of sperm from fertile men by increasing capacitation and/or acrosome reaction. The present study was conducted to investigate the effect of T alpha 1 on fertilizing capacity of sperm of infertile men using the sperm penetration assay (SPA) in a multicenter clinical trial. T alpha 1 significantly (p = .0006 to < .0001) increased (31 to 45%) fertilizing capacity of sperm of 76% (50/68) of infertile men as defined by the sperm penetration index in SPA. The enhancing effect of T alpha 1 and the degree of enhancement depended on the T alpha 1 concentration in the seminal plasma, since these parameters showed a significant intercorrelation (r = .65 to .74, p = .039 to .01). It would appear that T alpha 1 may have clinical application in the diagnosis and treatment of male infertility especially mediated through defective sperm function.

Acrosome↗

PubMedDate not supplied

Autoantigenicity of human sperm: molecular identities of sperm antigens recognized by sera of immunoinfertile men in the immunoprecipitation procedure.

Autoantigenicity of human sperm as related to immunoinfertility was investigated using the immunoprecipitation procedure. Sera from immunoinfertile men specifically immunoprecipitated six specific bands of 135, 95, and 65 kD and double bands of 47, 41, and 23 kD that were not recognized by the sera from fertile men. Of these six specific bands, three bands of 65-, 47-, and 23-kD molecular identities were recognized by > 60% of immunoinfertile sera, and 47 and 23 kD may correspond to the dimeric and monomeric forms of FA-1 antigen, respectively. Seminal plasma from immunoinfertile men specifically recognized three specific bands of 95, 37, and 16 kD; only the 95-kD band was also recognized with the immunoinfertile sera. These specific antigens may find applications in immunocontraception and immunoinfertility in humans.

Adult↗

PubMedDate not supplied

Protein tyrosine phosphorylation and signal transduction during capacitation-acrosome reaction and zona pellucida binding in human sperm.

During capacitation and acrosome reaction of human sperm, 7-14 proteins are phosphorylated, and two of these proteins (95 and 51 kD) are phosphorylated at tyrosine resides. The sperm proteins that bind ZP3 in humans have molecular identities of 95, 63, 51 (FA-1 antigen), and 14-18 kD, respectively. Three of these molecules, 95-, 51-, and 14-18-kD proteins, undergo tyrosine phosphorylation, and 51 kD (FA-1 antigen) also undergoes autophosphorylation. Many of the sperm proteins that participate in ZP binding are also involved in capacitation/acrosome reaction. These findings indicate a vital role of protein tyrosine phosphorylation and tyrosine receptor kinases in sperm capacitation, acrosome reaction, and ZP binding. Since tyrosine phosphorylation is the primary, or even exclusive, indication of signal transduction, it would appear that a signal transduction pathway is involved in these processes. However, the exact mechanism requires further study.

Acrosome↗

PubMedDate not supplied

Decreased levels of interleukin-12 are not correlated with leukocyte concentration and superoxide dismutase activity in semen of infertile men.

The interleukin (IL)-12 levels and the superoxide dismutase (SOD) activity were determined in the seminal plasma of fertile and infertile men with or without leukocytospermia by ELISA. The IL-12 levels differed significantly among the fertile and infertile groups, with the infertile groups showing lower levels that were not modulated by leukocytospermia. The SOD activity did not differ significantly among the fertile and infertile groups and was not correlated with the IL-12 levels. The positive correlation with sperm concentration suggests that IL-12 may have a direct or indirect role in male fertility/infertility and that its levels are not modulated by the presence of leukocytes in the semen.

Enzyme-Linked Immunosorbent Assay↗

PubMedDate not supplied

Effect of actinomycin D and cycloheximide on human sperm function.

The effects of actinomycin D and cycloheximide on human spermatozoal function were examined to investigate the potential transcriptional and translational activities of human sperm cell during capacitation/acrosome reaction. Treatment with actinomycin D significantly increased and treatment with cycloheximide decreased the acrosome reaction, and the penetration rates in the human sperm penetration of zona-free hamster oocytes assay (SPA). [35(S)]Methionine got incorporated into 3-9 de novo synthesized proteins present in the head and midpiece regions of the swim-up population of human sperm. Treatment with actinomycin D completely blocked and treatment with cycloheximide slightly reduced the synthesis of proteins. There seem to be some transcriptional and translational activities in the head and midpiece regions of human sperm during capacitation/acrosome reaction.

Acrosome Reaction↗

PubMedDate not supplied

Modulation of insulin-like growth factor-1 in the seminal plasma of infertile men.

It has been suggested that insulin-like growth factor (IGF)-1 plays an important role in the regulation of spermatogenesis in the testes. In the present study, concentrations of total IGF-1 were determined in the seminal plasma of fertile (n = 44), male-factor infertile (n = 34), and immunoinfertile (n = 10) men in order to investigate the role of IGF-1 in male infertility. Levels of IGF-1 were expressed both as nanograms per milliliter and as nanograms per milligram of protein. IGF-1 was detected in the seminal plasma of both fertile and infertile men. IGF-1 levels differed significantly between fertile and immunoinfertile groups (P < 0.035 to P < 0.0001), whether expressed as nanograms per milliliter or as nanograms per milligram of protein. The immunoinfertile group showed a 31.3-37.9% increase in the mean IGF-1 concentration over the fertile group. There was no statistical difference in the mean or median levels of IGF-1 between the fertile and male-factor infertile groups, whether expressed as nanograms per milliliter or as nanograms per milligram of protein. However, when the male-factor infertile subjects were divided into four subgroups based on which seminal parameter was defective, the subgroup having a low sperm count had IGF-1 levels that were significantly different from the fertile group, the immunoinfertile subgroup, and the other male-factor infertile subgroups. The low-sperm-count subgroup had the lowest mean and median IGF-1 levels of all the groups and subgroups tested. IGF-1 levels linearly correlated (r = 0.30-0.499) significantly (P = 0.023-0.027) with the total sperm count in the semen, whether analyzed with all groups together or in subgroups by condition. These findings suggest that IGF-1 has a role in fertility and that its derangement may be involved in male infertility, especially when mediated through low sperm count and immunologic factors.

Enzyme-Linked Immunosorbent Assay↗

PubMedDate not supplied

Presence and tyrosine phosphorylation of c-met receptor in human sperm.

The c-met receptor is a p190MET tyrosine kinase proto-oncoprotein that through its binding to its ligand, designated hepatocyte growth factor (HGF), induces mitogenic, motogenic, and morphogenic activities in a variety of cell types. The present study was conducted to examine whether or not the c-met receptor is expressed and tyrosine phosphorylated in the human sperm cell. The Western blot analysis, using a monoclonal antibody (MAb2) directed against the extracellular domain of the c-met receptor, showed a specific band of 195 kDa corresponding to the intact c-met receptor in the detergent-solubilized human sperm preparation (HSP). This protein band was not recognized by the control myeloma lg (immunoglobin). In the immunoprecipitation procedure, a similar specific band of 195 kDa and a 145-kDa band corresponding to the beta-subunit of c-met receptor were seen. In the indirect immunofluorescence technique, the c-met receptor was localized predominantly in the acrosomal region of the sperm cell. The c-met receptor was tyrosine phosphorylated/autophosphorylated during capacitation and in the cell-free in vitro kinase assay. Incubation of human sperm with hepatocyte growth factor (HGF) or MAb2 to c-met receptor enhanced the degree of tyrosine phosphorylation/autophosphorylation of the c-met receptor up to 5.1-fold. These findings indicate that the c-met receptor is present in the acrosomal region of human sperm cell and is tyrosine phosphorylated, which is enhanced by HGF and the receptor antibody. The c-met system may have an important role in sperm function.

Blotting, Western↗