Transmission of Immunity to Neisseria Gonorrhoeae from Vaccinated Hens to Embryos

Abstract

Presently, there is no practical laboratory animal model for the evaluation of experimental gonococcal vaccines. The chimpanzee has been used recently (1), but this animal is expensive and difficult to handle. On the other hand, the. susceptibility of the chick embryo to certain pathogenic microorganisms has provided an excellent model for the study of their virulence (2,3,8,9). In our laboratory, we have confirmed the original observation of Bumgarner et al (4), that Neisseria gonorrhoeae colony types T₁ and T₂ (virulent for man) are significantly more virulent for the chick embryo than T₃ and T₄ (non-virulent for man). However, chick embryo neutralization studies (4,5) have shown the unsuitability of the embryo as an animal model for the protective capacity of vaccines against gonorrhea, since there is only a ten-fold difference between the ability of normal and hyper-immune rabbit sera to protect the embryos against gonococcal challenge. Because of these limitations, we have investigated the ability of embryos obtained from Leghorn hens immunized intravenously with experimental gonococcal vaccines, to withstand a challenge with N. gonorrhoeae