Active immunization against riboflavin carrier protein results in peri-implantation embryonic loss leading to pregnancy termination in rats: use of alternate adjuvants.
To investigate the mechanism of pregnancy termination following immuno-neutralization of riboflavin carrier protein (RCP) and to use acceptable adjuvants, we actively immunized female rats with reduced and carboxymethylated RCP (RCM-RCP) using various adjuvants (during primary immunization) such as sodium phthalylated lipopolysaccharide (SPLPS), purified S. typhi outer membrane proteins (porins) and a combination of them. Rats (5-14 per group) were immunized with alugel adsorbed RCM-RCP (100 microg/dose) either alone or with SPLPS or porins or SPLPS+porins. Control animals received RCM-RCP emulsified with Fruend's completelincomplete adjuvants (FCA/FIA). All animals received five boosters at intervals of 21 days. The lowest (4 X 10(-3)) and the highest (> 70 X 10(-3)) anti-RCM-RCP antibody titers were observed in alugel adsorbed-RCM-RCP group and control groups, respectively. Immunized animals showed reduced fertility following 3rd, 4th and 5th boosters. Reduction in fertility was 30-60% in alugel adsorbed RCM-RCP group, 90-100% in FCA-RCM-RCP group and 80-90% in SPLPS+porins group. Fertility reduction was not strictly correlatable with the serum antibody titers. RCP-specific IgG could be localized in the uterine endometrial glands and luminal epithelial cells in the immunized animals. Animals in the FCA/FIA group showed abnormal implantation/resorption sites and their histological sections showed degenerated embryos. But, day 5 preimplantation embryos were normal. These results show that (a) SPLPS+porins can be used as adjuvants in place of FCA/FIA for active immunization against RCM-RCP and (b) early termination of pregnancy in the immunized animals is due largely to the failure of normal embryo implantation.
Rao
J
J
Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India.
Seshagiri
P B
PB
Shetty
G
G
Ramesh
G
G
Adiga
P R
PR
D000019:Abortifacient Agents / Q000494:pharmacology*; D000034:Abortion, Veterinary / Q000139:chemically induced*; D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D001391:Azo Compounds; D001755:Blastocyst; D002352:Carrier Proteins / Q000276:immunology*; D004717:Endometrium / Q000473:pathology; D005260:Female; D005313:Fetal Death / Q000139:chemically induced; D007074:Immunoglobulin G / Q000276:immunology; D008070:Lipopolysaccharides / Q000378:metabolism; D008297:Male; D026901:Membrane Transport Proteins; D008745:Methylation; D010446:Peptide Fragments / Q000276:immunology; D018272:Porins / Q000378:metabolism; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D012256:Riboflavin / Q000378:metabolism; D014343:Trypan Blue; D014611:Vaccination
D000019:Abortifacient Agents; D000276:Adjuvants, Immunologic; D001391:Azo Compounds; D002352:Carrier Proteins; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D026901:Membrane Transport Proteins; D010446:Peptide Fragments; D018272:Porins; C019079:riboflavin-binding protein; C009000:pontamine sky blue; D014343:Trypan Blue; D012256:Riboflavin