Evaluation of the immunocontraceptive potential of Escherichia coli-expressed recombinant dog ZP2 and ZP3 in a homologous animal model.
Dog zona pellucida glycoprotein 2 (dZP2), excluding the N-terminal signal sequence and the C-terminal transmembrane-like domain, was cloned and expressed as a polyhistidine fusion protein in Escherichia coli to evaluate the immunocontraceptive efficacy of ZP glycoproteins. The recombinant dZP2 (rec-dZP2) revealed a 70 kDa band corresponding to the full length transcript, as well as several low molecular mass fragments in western blot analysis. In addition to rec-dZP2, E. coli expressed recombinant dog ZP glycoprotein 3 (rec-dZP3), which has also been evaluated for its efficacy to block fertility in a homologous system. Three groups of female dogs (n = 4 per group) were immunized with rec-dZP2 conjugated to diphtheria toxoid (rec-dZP2-DT), rec-dZP3 conjugated to DT (rec-dZP3-DT) and DT alone. Immunization of female dogs with rec-dZP2-DT and rec-dZP3-DT led to generation of antibodies against the respective ZP proteins as well as to DT. Subsequent to mating, the four female dogs immunized with rec-dZP2-DT all conceived, which is indicative of failure of the anti-rec-dZP2 antibodies to block fertility. In the group of dogs immunized with rec-dZP3-DT, three of four animals did not conceive when mated with males of proven fertility. The block in fertility was associated with anti-dZP3 antibody titres. Ovarian histopathology revealed that the block in fertility in the group immunized with rec-dZP3-DT is probably manifested by inhibition in the development of follicles and is due to atretic changes in the zona pellucida. These results, although preliminary, indicate that immunization with dZP3 may be a feasible proposition to control dog populations provided that adequate antibody titres are achieved.
Srivastava
N
N
Gamete Antigen Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India.
Santhanam
R
R
Sheela
P
P
Mukund
S
S
Thakral
S S
SS
Malik
B S
BS
Gupta
S K
SK
D000818:Animals; D003269:Contraception, Immunologic / Q000662:veterinary*; D004168:Diphtheria Toxoid / Q000235:genetics*; D004285:Dogs; D004527:Egg Proteins / Q000235:genetics*; D004926:Escherichia coli / Q000378:metabolism; D005260:Female; D005822:Genetic Vectors / Q000008:administration & dosage*; D008562:Membrane Glycoproteins / Q000235:genetics*; D023421:Models, Animal; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage; D000072216:Zona Pellucida Glycoproteins
D004168:Diphtheria Toxoid; D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D000072216:Zona Pellucida Glycoproteins