Novel Sperm and Gonadotropin-releasing Hormone-based Recombinant Fusion Protein: Achievement of 100% Contraceptive Efficacy by Co-immunization of Male and Female Mice.
Improvements in long-term female contraception can be achieved by vaccinating with sperm-derived proteins. Here, recombinant proteins comprising either (i) N- (amino acid residues 1-80) or C- (amino acid residues 76-126) terminal fragments of mouse sperm protein 17 (Sp17) fused to the promiscuous T non-B cell epitope of tetanus toxoid (TT), amino acid residues 830-844 followed by di-lysine linker (KK) (TT-KK-Sp17Nor TT-KK-Sp17C, respectively) or (ii) mouse equatorin (amino acid residues 21-185) fused to the T non-B cell epitope of bovine RNase (amino acid residues 94-104) were expressed in Escherichia coli. Immunization of female FVB/J mice, using alum as an adjuvant, led to the generation of high antibody titers against the above proteins. Antibodies against both N- and C-terminal fragments of Sp17 reacted with the entire capacitated mouse spermatozoa, whereas those against equatorin reacted exclusively with the equatorial region. Despite the reactivity of all immune sera, only sera from mice immunized with TT-KK-Sp17Nand TT-KK-Sp17Csignificantly reduced mouse in vitro fertilization. Mating studies of the immunized females with un-immunized male mice revealed the highest infertility in the TT-KK-Sp17C-immunized group. In an attempt to further boost the immune response, the C-terminal fragment of Sp17 was expressed as fusion protein with a tandem repeat of gonadotropin-releasing hormone (GnRH) (Sp17C-GnRH2). Immunization of both male and female mice with Sp17C-GnRH2led to higher contraceptive efficacy compared to mice immunized with TT-KK-Sp17C. Interestingly, mating studies wherein partners were both immunized with Sp17C-GnRH2showed a complete failure of female mice to conceive. Thus, immunization of both males and females with Sp17C-GnRH2has the potential to increase contraceptive efficacy. Mol. Reprod. Dev. 83: 1048-1059, 2016. © 2016 Wiley Periodicals, Inc.
Reproductive Cell Biology Lab, National Institute of Immunology, New Delhi, India.|Lab of Molecular Reproduction, Department of Zoology, Delhi University, New Delhi, India.
Vidisha
V
Minhas
Reproductive Cell Biology Lab, National Institute of Immunology, New Delhi, India.
Abhinav
A
Shrestha
Embryo Biotechnology Lab, National Institute of Immunology, New Delhi, India.
Neerja
N
Wadhwa
Lab of Molecular Reproduction, Department of Zoology, Delhi University, New Delhi, India.
Rita
R
Singh
Reproductive Cell Biology Lab, National Institute of Immunology, New Delhi, India.
Satish Kumar
SK
Gupta
D000818:Animals; D002148:Calmodulin-Binding Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D003269:Contraception, Immunologic / Q000379:methods*; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D018984:Epitopes, T-Lymphocyte / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D007114:Immunization; D008297:Male; D008565:Membrane Proteins; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D013745:Tetanus Toxoid / Q000235:genetics / Q000276:immunology / Q000494:pharmacology
D002148:Calmodulin-Binding Proteins; D002352:Carrier Proteins; D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; C490357:Spa17 protein, mouse; D013745:Tetanus Toxoid; D007987:Gonadotropin-Releasing Hormone