The chicken and egg system for the development of anti-idiotypic vaccines

Abstract

This study investigates the use of the chicken and egg system for the development of an oral HIV vaccine. Brown leghorn chickens were immunized with keyhole limpet hemocynin conjugated with a HIV-gp120 peptide (fragment 254-274). An indirect ELISA for antibodies to HIV-gp120 was used to measure anti-HIV antibody titres in the watery soluble fraction of eggs up to 14 weeks after the second week post-immunization. Over a period of 10 weeks, 3 cats were fed with the eggs from the immunized chickens and 2 cats with eggs from non-immunized chickens. An indirect enzyme linked-immunosorbent assay (ELISA) and a binding inhibition assay were used to assess the antibody response to HIV-gp120 peptide in the cat serum. The most important finding was the development of serum anti- HIV antibodies in cats fed with eggs from chickens that were positive for anti-HIV antibodies. These feline anti-HIV antibodies bound to the original HIV-gp120 peptide and also inhibited the binding of egg yolk anti-HIV antibodies to the HIV gp120 peptide, showing that the anti-HIV antibody raised in cats after feeding, was an anti-anti-idiotypic antibody. The results of this study suggest that eggs from immunized hens could be considered in the management of HIV infections. © 2012 Vaillant AAJ, et al.