Expression of AniA, the major anaerobically induced outer membrane protein of Neisseria gonorrhoeae, provides protection against killing by normal human sera.

Anaerobically grown Neisseria gonorrhoeae has previously been shown to have elevated serum resistance in the absence of exogenous CMP-N-acetylneuraminic acid or detectable sialylation. We hypothesized that the anaerobically induced gonococcal outer membrane protein AniA might have a role in this phenomenon, as it is the only known gonococcal protein that is absent under aerobic conditions. An N. gonorrhoeae F62 derivative, RUG7035, in which aniA is under control of the tac promoter, was used to examine the effect of AniA expression on serum resistance. In this study, we found that expression of AniA enhanced the serum resistance of N. gonorrhoeae and may account for these earlier observations.