CROSS-REACTING SERUM OPSONINS TO MENINGOCOCCI AFTER VACCINATION

The opsonic activity of sera from healthy volunteers immunized with an outer membrane vesicle vaccine prepared from a Neisseria meningitidis (class 3, 44/76, B:15:P1.7,16), characteristic of the present Norwegia n epidemic, has been examined. A marked increase in the phagocytosis o f class 3 and nontypeable strains of different serogroups, serotypes, and serosubtypes was demonstrated in the presence of postvaccination s era. Sera from vaccinees also caused a significant increase in leukocy te oxidative metabolism as measured by luminol-enhanced chemoluminesce nce during phagocytosis of class 3 and nontypeable meningococci. An in crease in serum opsonins cross-reacting with class 2 (type 2a) meningo cocci of different serogroups was not observed, suggesting that future meningococcal outer membrane vesicle vaccine preparations should cont ain both class 2 and class 3 porins in geographic areas where both cla ss 2 and class 3 strains cause disease.