Serum immune response to common pathogenic Neisseria antigen H8 in patients with uncomplicated gonococcal infection and pelvic inflammatory disease

A distinct outer membrane antigen, H8, is expressed in all strains of N. gonorrhoeae and N. meningitidis but is rarely found in nonpathogenic Neisseria. H8 has been shown previously to be immunogenic in disseminated gonococcal and meningococcal infections. In this study we examined the IgG antibody responses to H8 in 160 serum samples obtained serially from 33 patients who experienced 42 separate episodes of uncomplicated gonococcal infection (UGC) or pelvic inflammatory disease (PID). 7/21 patients with PID and 13/21 patients with UGC demonstrated an immune response to H8 that was generally short-lived (< 6 months). Mean peak titers were higher in patients with UGC than in patients with PID but were not influenced by a history of prior infection. The 9 patients who were reinfected during the study either showed no antibody response to H8 or had experienced a fourfold drop in titer at the time of diagnosis of reinfection.