PubMed Health⌕ Search

Biomedical subjects

Rajesh K Naz

Publications and source records attributed to Rajesh K Naz.

At least 19 recordsLinked to original sources

Peptide vaccines against cancer, infectious diseases, and conception.

The concept of peptide vaccines is based on identification and chemical synthesis of B-cell and T-cell epitopes which are immunodominant and can induce specific immune responses. B-cell epitope of a target molecule can be coupled to a promiscuous T-cell epitope to make it immunogenic. Our increased understanding of antigen recognition at molecular level has resulted in the development of rationally designed peptide vaccines. The relative ease of construction and production, chemical stability, and lack of oncogenic or infectious potential has made the peptides attractive vaccine candidates. However, several obstacles limit the widespread usefulness of peptide vaccines. These include their low immunogenicity, need for a better adjuvant and carrier, and reliable and simple assays to measure T-cell response. Nonetheless, current efforts are defying these limitations and many promising discoveries are making their way to improve this approach. The peptide vaccines against various cancers have undergone phase I and phase II clinical trials with successful immunological clinical outcome. The peptide vaccination is being examined both for palliative and prophylactic immunotherapy. The current status of many peptide vaccines which are being developed against cancer, infectious diseases, and conception is discussed in this review.

Animals↗

Molecular identities of human sperm proteins reactive with antibodies in sera of immunoinfertile women.

Antisperm antibodies (ASA) can cause infertility in both men and women. It is important to delineate the sperm antigens against which these ASA are directed. Sperm proteins were separated by 2D gel electrophoresis and transferred to nitrocellulose membrane and incubated with sera from fertile women or immunoinfertile women having ASA. The corresponding immunoreactive peptide spots were cored from the gel and analyzed by the two-dimensional (2D) gel electrophoresis/matrix-assisted laser desoprtion ionization-time of flight-mass spectrometry and liquid chromatography-mass spectrometry (MALDI-TOF-MS/LC-MS). A total of 68 spots belonging to 38 different proteins and their isomers were identified. Fourteen of these proteins and their isomers reacted with both the fertile and immunoinfertile sera. Twenty-four of these proteins reacted specifically only with the immunoinfertile sera and not with the fertile sera. Among them was a novel protein designated as a hypothetical protein FLJ32704 (accession # Q96MA6). An immunodominant sequence (amino acid 151-159) of this protein was identified and a nonamer peptide based upon this sequence (IQTLG1TPR) was synthesized and examined for its immunoreactivity. This synthetic peptide reacted with 90% (36/40) of immunoinfertile sera and not with any of the fertile sera (0/40) in the enzyme-linked immnosorbent assay (ELISA). In conclusion, using the 2D gel electrophoresis/MALDI-TOF-MS/LC-MS procedure, we have identified several known and at least one novel antigen against which the antibodies are present in sera of immunoinfertile but not fertile women. Some of these antigens may find applications in specific diagonsis and treatment of infertility/immunoinfertility, and in the development of new generation of contraceptive modalities including contraceptive vaccines.

Adult↗

Effect of sperm DNA vaccine on fertility of female mice.

Our laboratory has identified a sperm-specific dodecamer peptide sequence, designated as YLP(12), vaccination with which causes a long-term reversible immunocontraceptive effect in female mice. In the present study, the effects of YLP(12) DNA vaccine were examined. YLP(12) 36 bp cDNA was cloned into pVAX1 vector to prepare the DNA vaccine. Two additional vaccine constructs were made by in frame cloning of one and two CpG repeats in the YLP(12)-cDNA vaccine. Five groups of female mice were immunized intradermally by using gene gun with YLP(12)-cDNA, YLP(12)-cDNA-CpG, YLP(12)-cDNA-CpG-CpG, YLP(12)-cDNA mixed with exogenous synthetic CpG oligodeoxynucleotide (ODN), or vector DNA alone, respectively. Vaccination with all three constructs and the YLP(12) vaccine mixed with exogenous ODN raised antibody response both in the sera as well as locally in the vaginal tract. There was no antibody response in the mice injected with the vector alone. In sera, the highest titers were obtained for the IgG class for all constructs and formulation followed by IgA class. In vaginal washings the highest titers were obtained for the IgA class followed by IgG class. Within the IgG class, the titers for the IgG2a subclass were significantly greater than the IgG1 subclass. Immunization with all constructs and formulation caused a significant (P < 0.05 to <0.001) reduction (20-43%) in fertility of female mice. The highest reductions were seen in mice immunized with YLP(12)-cDNA-CpG-CpG (two repeats) (43% reduction) and with the YLP(12) vaccine administered with exogenous CpG ODN (42% reduction). T lymphocytes obtained from DNA-vaccinated mice showed clearly distinguished comparative RT-PCR analysis of cytokine mRNA expression for Th1 and Th2 immune responses compared to T lymphocytes obtained from control animals injected with vector DNA. Expression of both Th1 cytokines (IL-2 and IFN-gamma) and Th2 cytokines (IL-4 and IL-10) was enhanced after DNA vaccination as compared to controls, with a bias towards Th1 response. The immunocontraceptive effects were long-lasting observed up to 1.3 years of the observation period and increased with time. These novel findings indicate that the intradermal immunization with a sperm-specific DNA vaccine causes a long-term circulating and local immune response resulting in immunocontraceptive effects in female mice.

Animals↗

Effect of fertilization antigen (FA-1) DNA vaccine on fertility of female mice.

Vaccination of female mice with recombinant fertilization antigen (FA-1) causes a long-term reversible contraceptive effect. Also, a DNA vaccine based upon a dodecamer sequence YLP(12) present in sperm causes a reduction in fertility. In the present study, the effects of FA-1 DNA vaccine alone, and FA-1 and YLP(12) DNA vaccines together were examined. FA-1 495-bp DNA was cloned into pVAX1 vector to prepare the DNA vaccine. Four groups of female mice were immunized intradermally by using a gene gun with FA-1 DNA, FA-1 DNA + YLP(12) DNA, FA-1 DNA + YLP(12) DNA mixed with exogenous synthetic CpG oliogodeoxynucleotide (ODN), or vector DNA alone, respectively. Vaccination with all three formulations caused a significant reduction in fertility, with FA-1 DNA + YLP(12) DNA mixed with exogenous synthetic CpG ODN showing the highest reduction. Vaccination with all three formulations raised antibody response in both the sera as well as locally in the vaginal tract, with ODN mixed group demonstrating the highest titers. There was no antibody response in the mice injected with the vector alone. In sera, the highest titers were obtained for the IgG class for all vaccine formulations followed by the IgA class. In vaginal washing, the highest titers were obtained by the IgA class followed by the IgG class. Within the IgG class, the titers for the IgG2a subclass were significantly greater than the IgG1 subclass. The immunocontraceptive effects were long-lasting over 1 year of the observation period and increased with time. These novel findings indicate that the intradermal immunization with a sperm-specific FA-1 DNA vaccine causes a long-term circulating and local immune response resulting in immunocontraceptive effects in female mice. The anti-fertility effects were enhanced when FA-1 DNA vaccine was combined with YLP(12) DNA vaccine and injected with ODN.

Animals↗

Novel testis/sperm-specific contraceptive targets identified using gene knockout studies.

The population explosion and unintended pregnancies resulting in elective abortions continue to be the major public health issues in spite of availability of current methods of contraception. There is an urgent need for a better method of contraception that is accepted, effective, and available. Various targets are being investigated that can be used for contraception. The gene knockout technology is a powerful approach to identify such novel targets. Using search in the database, at least 93 genes were identified in the literature whose deletion demonstrated an effect on fertility in male mice. However, majority of these knockouts also demonstrated an effect on non-reproductive organs concomitant with an effect on fertility. The knockouts of only a few genes/proteins induced a specific effect on fertility without a serious side effect. The potential role of these novel genes/proteins in contraception/contraceptive vaccine development is discussed.

Animals↗

Gene knockouts that cause female infertility: search for novel contraceptive targets.

The gene knockout technology has revolutionized the fertility/infertility field. It has revealed several essential previously undiscovered molecules, new insights and novel mechanisms involved in steps of the fertility cascade in females. Using database and literature search, knockouts of at least 83 genes were discovered that demonstrated an effect on fertility of female mice. These effects ranged from abnormality in reproductive structure, ovarian function, oocyte, fertilization, embryonic and fetal development, implantation and pregnancy to delivery. However, only a few of these knockout of genes such as encoding oocyte glycoprotein coat comprised of zona pellucida (ZP) 1, ZP2 and ZP3 and oocute plasma membrane specific proteins showed a specific and exclusive target infertility effect without concomitant effects on the non-reproductive organ system. These molecules will provide novel targets of contraception including contraceptive vaccine development.

Animals↗

Recent advances in contraceptive vaccine development: a mini-review.

Contraceptive vaccines (CV) may provide viable and valuable alternatives to the presently available methods of contraception. The molecules that are being explored for CV development either target gamete production [luteinizing hormone-releasing hormone (LHRH)/GnRH, FSH], gamete function [sperm antigens and oocyte zona pellucida (ZP)], and gamete outcome (HCG). CV targeting gamete production have shown varied degrees of efficacy; however, they either affect sex steroids causing impotency and/or show only a partial rather than a complete effect in inhibiting gametogenesis. However, vaccines based on LHRH/GnRH are being developed by several pharmaceutical companies as substitutes for castration of domestic pets, farm and wild animals, and for therapeutic anticancer purposes such as in prostatic hypertrophy and carcinoma. These vaccines may also find applications in clinical situations that require the inhibition of increased secretions of sex steroids, such as in uterine fibroids, polycystic ovary syndrome, endometriosis and precocious puberty. CV targeting molecules involved in gamete function such as sperm antigens and ZP proteins are exciting choices. Sperm constitute the most promising and exciting target for CV. Several sperm-specific antigens have been delineated in several laboratories and are being actively explored for CV development. Studies are focused on delineating appropriate sperm-specific epitopes, and increasing the immunogenicity (specifically in the local genital tract) and efficacy on the vaccines. Anti-sperm antibody (ASA)-mediated immunoinfertility provides a naturally occurring model to indicate how a vaccine might work in humans. Vaccines based on ZP proteins are quite efficacious in producing contraceptive effects, but may induce oophoritis, affecting sex steroids. They are being successfully tested to control feral populations of dogs, deer, horses and elephants, and populations of several species of zoo animals. The current research for human applicability is focused on delineating infertility-related epitopes (B-cell epitopes) from oophoritis-inducing epitopes (T-cell epitopes). Vaccines targeting gamete outcome primarily focus on the HCG molecule. The HCG vaccine is the first vaccine to undergo Phase I and II clinical trials in humans. Both efficacy and lack of immunopathology have been reasonably well demonstrated for this vaccine. At the present time, studies are focused on increasing the immunogenicity and efficacy of the birth control vaccine, and examining its clinical applications in various HCG-producing cancers. The present article will focus on the current status of the anti-sperm, anti-ZP, anti-LHRH/GnRH and anti-HCG vaccines.

Animals↗

Search for peptide sequences involved in human antisperm antibody-mediated male immunoinfertility by using phage display technology.

The aim of the present study was to delineate peptide sequences against which antisperm antibodies (ASA) are raised in immunoinfertile men. Using the phage display technology, seven unique and novel dodecamer amino acid sequences were identified that reacted with the sera of immunoinfertile men. The peptides were synthesized based upon these amino acid sequences and examined for their immunoreactivity with sera from ASA-positive immunofertile men (n = 15) and ASA-negative fertile men (n = 18) for IgM, IgG, and IgA class of antibody in the enzyme-linked immunosorbent assay (ELISA). All the seven synthetic peptides showed a significantly (P < 0.001) higher mean absorbance values for IgG and/or IgA class of antibody with the immunoinfertile sera compared to fertile control sera. Three of the seven peptides demonstrated a stronger reaction (>2 SD units) with 27%-40% of immunoinfertile sera compared to fertile controls. These peptide sequences may find applications in the specific diagnosis and treatment of immunoinfertility and in contraceptive vaccine development. The phage display technique provides an exciting and novel technology to delineate sperm epitopes involved in immunoinfertility.

Adult↗

Antisperm vaccine for contraception.

PROBLEM: This study is a review of antisperm contraceptive vaccine (CV) development with the main focus on research going on in our laboratory. METHOD OF STUDY: Various methods of proteomics and genomics, hybridoma technology, substractive libraries, differential display method, and phage display technology were used to obtain sperm-specific genes and proteins. The present study will primarily focus on the sequences obtained by using the phage display technology and their role in CV development and human immunoinfertility. RESULT: Four novel peptides, delineated by using the phage display technology, were found to be involved in human immunoinfertility. The vaccine based on one of these peptides, designated as YLP(12), caused a reversible contraception in female mice. CONCLUSIONS: The vaccine targeting sperm is a feasible and exciting approach to contraception. The phage display technology is a powerful tool to delineate sperm-specific peptide sequences that can be used for the CV development and in the diagnosis and treatment of infertility mediated through antisperm antibodies.

Animals↗

Contraceptive vaccines.

The world's population is growing at a tremendous rate, affecting growth and development. Apart from this population growth, unintended pregnancies resulting in elective abortions continue to be a major public health issue. In over half of these unintended pregnancies, the women have used some type of contraception. Thus, there is an urgent need for a better method of contraception that is acceptable, effective and available. The contraceptive choices available to women at this time include steroid contraceptives, intrauterine devices, barrier methods, spermicides, natural family planning, male and female sterilisation, and recently available emergency contraceptives. Contraceptive vaccines (CVs) may provide viable and valuable alternatives that can fulfill most, if not all, properties of an ideal contraceptive. Since both the developed and most of the developing nations have an infrastructure for mass immunisation, the development of vaccines for contraception is an exciting proposition. The molecules that are being explored for CV development either target gamete production (gonadotropin releasing hormone, follicle-stimulating hormone and luteinising hormone), gamete function (zona pellucida [ZP] proteins and sperm antigens) or gamete outcome (human chorionic gonadotropin [hCG]). Disadvantages of CVs targeting gamete production are that they affect sex steroids and/or show only a partial effect in reducing fertility. CVs targeting gamete function are better choices. Vaccines based on ZP proteins are quite efficacious in producing contraceptive effects. However, they invariably induce oophoritis affecting sex steroids. Sperm antigens constitute the most promising and exciting targets for CVs. Several sperm-specific antigens have been delineated in several laboratories and are being actively explored for CV development. Antisperm antibody-mediated immunoinfertility provides a naturally occurring model to indicate how an antisperm vaccine will work in humans. Vaccines targeting gamete outcome primarily focus on the hCG molecule. The hCG vaccine is the first vaccine to undergo phase I and II clinical trials in humans. Both the efficacy and the lack of immunotoxicity have been reasonably well demonstrated for this vaccine. The present studies focus on increasing the immunogenicity and efficacy of this birth control vaccine.

Female↗

Role of tyrosine phosphorylation in sperm capacitation / acrosome reaction.

Capacitation is an important physiological pre-requisite before the sperm cell can acrosome react and fertilize the oocyte. Recent reports from several laboratories have amply documented that the protein phosphorylation especially at tyrosine residues is one of the most important events that occur during capacitation. In this article, we have reviewed the data from our and other laboratories, and have constructed a heuristic model for the mechanisms and molecules involved in capacitation/acrosome reaction.

Acrosome Reaction↗

Cloning and sequencing of a cDNA encoding for a protein specifically expressed in human testis, ovary and placenta.

Reproductive cell/tissue-specific antigens are attractive candidates for the development of a contraceptive vaccine. Using the differential display technology, a human cDNA fragment of 322-bp, designated as T17, was identified showing specific expression in the human testis. The T17 cDNA fragment was used as a probe to screen the human testis cDNA-lambda gt10 library. After screening, one positive clone of approximately 1.1 kb having T17 nucleotide (nt) sequence was obtained. The 5' and 3' termini of this cDNA clone were extended by using 5' and 3' RACE procedures that yielded a full-length cDNA, designated as the TOP gene. The TOP cDNA is 1,480-bp long and has an ORF of 463 aa with the first ATG Met start codon at nucleotide (nt) 64 and the stop codon TGA at nt 1452. The translated protein has a calculated molecular mass of 49.3 kD with isoelectric point of 12.17. The deduced amino acid (aa) has one potential N-glycosylation site, and several phosphorylation and myristoylation sites. Hydropathy plot generated from the deduced aa sequence showed it to be a surface protein. Comprehensive computer search in the database did not reveal any homology to any existing sequences both at the nt and aa levels. The TOP cDNA was found to be completely localized on the human chromosome 16 at the nt position 507833-506354, with the TOP ORF at the nt position 507770-506354. Northern blot analysis using three human Northern blots, indicated the specific expression of TOP gene in the human testis, ovary and placenta. RT-PCR-Southern blot analysis also confirmed tissue-specific expression of the TOP gene. The TOP cDNA may help us to gain insight into transcriptional control of the differentially expressed reproductive tissue-specific genes. It may also find clinical applications in the development of a contraceptive vaccine, and specific diagnosis and treatment of infertility in humans.

Blotting, Northern↗

Passive immunization for immunocontraception: lessons learned from infectious diseases.

Development of vaccine for contraception is an exciting proposition that could provide a valuable alternative to the presently available methods for birth control. Various targets such as gonadotropin releasing hormone (GnRH), follicle stimulating hormone (FSH), leutinizing hormone (LH), zona pellucida (ZP) antigens, sperm antigens, and human chorionic gonadotropin (hCG) are being explored for immunocontraception. Besides specific concerns associated with each contraceptive vaccine, the progress has been restricted by the variability of the immune response after active immunization, attain and maintain high antibody titers, time lag to achieve reasonably good antibody titers, and uncertainty regarding how long the bioeffective antibodies will remain in circulation. It is envisaged that these concerns may be taken care of by using the preformed antibodies in the passive immunization approach. The antibody therapies have been tried and found to be successful against various infectious diseases both in animals as well as humans. Some have become treatment modalities in the clinics. This manuscript will review the data available for the passive immunization of preformed polyclonal and murine/humanized/human monoclonal antibodies, their efficacy, mode of delivery, duration of the effects, and limitations, if any. The overall objective is to examine the feasibility and practicability of the passive immunization approach for immunocontraception.

Animals↗

Modalities for treatment of antisperm antibody mediated infertility: novel perspectives.

Immunoinfertility because of antisperm antibodies (ASA) is an important cause of infertility in humans. The incidence of ASA in infertile couples is 9-36% depending on the reporting center. Early claims regarding the incidence and involvement of ASA in involuntary infertility were probably overemphasized, which has resulted in subsequent confusion, doubt, and underestimation of their clinical significance. No immunoglobulin that binds to sperm should be called an antisperm antibody in a strict sense unless it is directed against a sperm antigen that plays a role in fertilization and fertility. ASA directed against the fertilization-related antigens are more relevant to infertility than the immunoglobulins that bind to sperm associated antigens. Several methods have been reported for treatment of immunoinfertility. These include: immunosuppressive therapies using corticosteroids or cyclosporine; assisted reproductive technologies such as intrauterine insemination, gamete intrafallopian transfer, in vitro fertilization, and intracytoplasmic sperm injection; laboratory techniques such as sperm washing, immunomagnetic sperm separation, proteolytic enzyme treatment, and use of immunobeads. Most of the available techniques have side effects, are invasive and expensive, have low efficacy, or provide conflicting results. Recent findings using defined sperm antigens that have a role in fertilization/fertility have provided animal models and innovative novel perspectives for studying the mechanism of immunoinfertility and possible modalities for treatment. The better understanding of local immunity and latest advances in hybridoma and recombinant technologies, proteomics and genomics leading to characterization of sperm antigens relevant to fertility will help to clarify the controversy and to establish the significance of ASA in infertility.

Adrenal Cortex Hormones↗

A novel human prostate-specific gene-1 (HPG-1): molecular cloning, sequencing, and its potential involvement in prostate carcinogenesis.

Prostate-specific genes that have a role in normal and abnormal prostate growth are needed for early and specific diagnosis and treatment of prostate cancer. In the present study, the differential display-PCR technique was used to obtain a prostate-specific approximately 339-bp cDNA fragment. On screening the human-prostate lambdagt10 library with this fragment, a full-length 1468-bp human prostate-specific gene (HPG-1) with an open reading frame of 127 amino acids (aa) was retrieved. Extensive database search revealed that the HPG-1 has novel nucleotide/aa sequences. It was localized on Homo sapiens 3q26 chromosomal locus, a region that has been shown to be involved in prostate carcinoma. The computer-generated translated protein has a calculated molecular mass of 14.8 kDa with several potential glycosylation and phosphorylation sites including two N-linked glycosylation, one tyrosine phosphorylation, and one N-myristoylation sites. The in vitro transcription and translation procedures using HPG-1 cDNA yielded a protein of similar molecular mass of approximately 15 kDa. Hydrophilicity analysis of the deduced aa sequence indicated that HPG-1 is a membrane-anchored/attached protein. Analysis for tissue specificity by using the Northern blot and reverse transcription-PCR-Southern blot procedures using 19 different human tissues revealed that HPG-1 is expressed specifically only in prostate tissue. To examine its involvement in prostate carcinogenesis, three prostate cancer epithelial cell lines, one androgen-responsive (LNCaP) and two androgen-nonresponsive (DU-145 and PC-3), were examined for the expression of HPG-1. Using the Northern blot and quantitative reverse transcription-PCR procedures it was found that LNCaP and DU-145 cells and not the PC-3 cells have HPG-1 expression, with LNCaP cells having approximately 2-3-fold higher levels of HPG-1 mRNA transcripts compared with DU-145 cells. In vitro culture of LNCaP cell with antisense and not the sense oligonucleotide decreased the HPG-1 mRNA levels and inhibited the cell growth in a concentration-dependent manner; at 72 h there was an 86% inhibition of cell growth. HPG-1 mRNA expression in LNCaP cells was found to be responsive to androgen. Thus, the novel androgen-responsive HPG-1, which has prostate-specific expression and seems to be involved in carcinogenesis, may have applications in the specific diagnosis and treatment of prostate cancer.

Amino Acid Sequence↗

Novel human prostate-specific cDNA: molecular cloning, expression, and immunobiology of the recombinant protein.

The differential display-polymerase chain reaction technique was employed to obtain a prostate-specific approximately 300-bp cDNA fragment. On screening the human prostate-lambdagt10 library with this fragment, a full-length approximately 1.5-kb cDNA encoding for a prostate antigen, designated as human novel prostate-specific antigen (hNPSA), was found. Extensive database searches revealed that the hNPSA cDNA is a novel sequence. It has an open reading frame (ORF) of 735-bp encoding for 245 amino acids (aa), with a calculated molecular mass of approximately 27kDa. Hydrophilicity analysis of the deduced aa sequence indicated that hNPSA is a membrane-anchored peptide. Analysis for tissue-specificity by Northern blot and RT-PCR-Southern blot procedures indicated that hNPSA is specifically expressed only in human prostate. The hNPSA (ORF) was subcloned into pET22b(+) vector and expressed using the histidine-tagged gene fusion system. The recombinant (r) protein of approximately 27kDa was purified and antibodies (Ab) were raised in rabbits. The rhNPSA Ab recognized a specific protein band of approximately 35kDa in solubilized human prostate tissue and not in any of the other 10 human tissues tested in the Western blot procedure. The hNPSA expression is upregulated 2.5- to 3-fold, both at the mRNA and protein levels in androgen-dependent LNCaP cells, as compared to normal whole prostate tissue. Antisense, but not the sense, phosphothiorate-conjugated oligonucleotides based on the hNPSA cDNA sequence significantly (p<0.001) inhibited proliferation of LNCaP cells in a concentration-dependent manner. Thus, the novel hNPSA, which has prostate-specific expression and seems to be involved in carcinogenesis, may have applications in the specific diagnosis and treatment of prostate cancer.

Amino Acid Sequence↗

Molecular cloning and sequencing of cDNA encoding for human FA-1 antigen.

The cDNA encoding for the human FA-1 sperm antigen was cloned and sequenced from the in-house constructed subtractive human testis cDNA expression library in lambda Ziplox using the FA-1 monoclonal antibody (mAb). The full--length sequence was obtained by using the 5' rapid amplification of 5'-cDNA end (5'-RACE) procedure. It is 1,576-bp long, and has an open reading frame (ORF) of 283 amino acids (aa) with the first ATG Met start codon at nucleotide (nt) 57 and the stop codon TAG at nt 906. It has two termination codons at the 5' end before the ATG start codon. The translated protein has a calculated molecular weight of 32.1 kDa and estimated isoelectric point (pI) of 11.59. It has one potential N-linked glycosylation site and one tyrosine phosphorylation site, besides several O-linked glycosylation and serine and threonine phosphorylation sites. Hydrophilicity analysis of the deduced aa sequence showed it to be a membrane-anchored protein. Extensive computer search in the database did not identify any known nt/aa sequence having homology with FA-1 cDNA or deduced aa, indicating it to be a novel gene. The Northern blot and reverse transcription-polymerase chain reaction (RT-PCR)-Southern blot analyses indicated the testis-specific expression of FA-1 antigen at the mRNA level. The ORF of the FA-1 was subcloned into pGEX- 1lambda T for expression. The expressed FA-1 recombinant protein had a molecular size of approximately 40 kDa, and was recognized by the FA-1 mAb, and not by the myeloma control Ig. The rabbit antibodies (Ab) raised against the recombinant (r) FA-1 antigen recognized the rFA-1 antigen as well as the native (n) FA-1 antigen. The rFA-1 Ab specifically recognized a protein band of approximately 50 kDa in human testis extract in the Western blot involving 11 types of human tissue extracts, indicating the testis-specific expression of FA-1 at the protein level. The Ab showed binding with live and methanol-fixed human sperm at the post-acrosomal, mid-piece, and tail regions. The Ab caused a significant (P < 0.001) and concentration-dependent inhibition of human sperm capacitation/acrosome reaction by blocking tyrosine phosphorylation of the FA-1 antigen. The sperm-specific human FA-1 recombinant antigen may find applications in immunocontraception, and diagnosis and treatment of immunoinfertility in humans.

Acrosome Reaction↗