Serum antibody response to the 70,000-molecular-weight neisserial common antigen in humans infected by Neisseria gonorrhoeae.

We evaluated the presence of antibodies directed against a 70,000-molecular-weight (70K) common neisserial antigen in sera from patients with first or repeated gonococcal infections and in sera from healthy controls. Sera were taken as soon as possible after the onset of disease, and anti-70K antibodies were detected by Western blot (immunoblot). Results show that significantly fewer patients with gonococcal infection possessed anti-70K antibodies than controls (P less than 0.001). This suggests a possible role of anti-70K antibodies in natural immunity against Neisseria gonorrhoeae.