The lipopolysaccharide (R type) as a common antigen of Neisseria gonorrhoeae. I. Immunizing properties

Abstract

The ability of R-type lipopolysaccharide (LPS), isolated from Neisseria gonorrhoeae colony type 4, to protect against infection with N. gonorrhoeae colony type 1 (T1 isolates) in the mouse and chicken embryo was investigated. C57 black mice were immunized intraperitoneally with 50 μg of LPS, and challenged intracerebrally with 10–20 LD50's of N. gonorrhoeae colony type 1. Immunized mice were significantly protected (P < 0.01 to < 0.05) against challenge with different T1 isolates of N. gonorrhoeae when compared with non-immunized mice. Mice, injected with succinylated or alkali-treated LPS were not protected against gonococcal challenges.In a second animal model, leghorn hens were immunized intravenously with three injections of 500 μg of LPS followed by a booster of 2.5 mg 2 weeks later. Embryonated eggs obtained from immunized hens were protected against challenge with 5 × 103 – 1 × 104 LD50's of three different T1 isolates. When hens were injected with the chemically modified LPS, the embryos were not resistant to gonococcal challenge. The results of this study demonstrate the ability of R-type gonococcal LPS to provide protection against different T1 isolates of N. gonorrhoeae.