Cross-Reacting Serum Opsonins to Meningococci after Vaccination

Abstract

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 Norwegian epidemic, has been examined. A marked increase in the phagocytosis of class 3 and nontypeable strains of different serogroups, serotypes, and serosubtypes was demonstrated in the presence of postvaccination sera. Sera from vaccinees also caused a significant increase in leukocyte oxidative metabolism as measured by luminol-enhanced chemoluminescence during phagocytosis of class 3 and nontypeable meningococci. An increase in serum opsonins cross-reacting with class 2 (type 2a) meningococci of different serogroups was not observed, suggesting that future meningococcal outer membrane vesicle vaccine preparations should contain both class 2 and class 3 porins in geographic areas where both class 2 and class 3 strains cause disease.

Immune Response Induction and New Effector Mechanisms Possibly Involved in Protection Conferred by the Cuban Anti-Meningococcal BC Vaccine

“…In addition, the influence of complement on this activity is a well-known phenomenon confirmed in this study. Opsonins against N. meningitidis B have also been reported by others (15,46). Opsonic activity was also detected in sera from subjects immunized with the Norwegian vaccine (1).…”

“…The criteria are based on the necessity of close contact between IgG antibodies (the main antibody class that should be induced by an effective parenteral vaccine) in order to activate complement; the relative dispersion of outer membrane proteins on the bacterial surface; and the relative inaccessibility of these proteins, not only structural but also in the antigenic sense, created by a nonxenogenic capsular B polysaccharide (8,22,38). The IgG antibodies with bactericidal activity also have other important biological functions (e.g., as opsonins), and the induction of complement-fixing antibodies is more related to the Th1 pattern of cytokine production (15). This implies that other mechanisms could be present, such as IFN-␥-mediated phagocyte activation (28) in addition to bactericidal antibodies.…”

“…This result suggests that PMN are essential in the defense against this infection, at least in rat models. It is important to note that peripheral blood in the rat consists of only 25% PMN (15); thus, PMN may be even more influential in humans, where the percentage is higher (60 to 70%).…”

Serum Bactericidal Activity and Induction of Chemiluminescence of Polymorphonuclear Leukocytes: Complement Activation Pathway Requirements in Defense against <i>Neisseria meningitidi</i><i>s</i>

“…In contrast, CL responses were obtained in the absence of C5. Responses of this kind have previ ously been shown to reflect phagocytosis [14], even though the correlation might not be entirely strict [30]. Judging from the lack of response following addition of Clq to heat-inactivated pooled normal human serum, PMNL Clq receptors [12,29] did not play an important role in our as say system.…”

The PorB porin from commensal Neisseria lactamica induces Th1 and Th2 immune responses to ovalbumin in mice and is a potential immune adjuvant

“…Neisseria lactamica (Nlac) strain Y92-1009 [54] (a gift from A. Gorringe, HPA, Porton Down, Salisbury, UK) was originally isolated in Northern Ireland and is part of the ST-613 clonal complex, and N. meningitidis (Nme) strain H44/76 Δ1Δ4 [55] were grown on chocolate-agar plates containing 1% Isovitalex in a 37°C in a 5% CO 2 incubator. Murine B cells were isolated from C57Bl/6J mice and C3H/HeJ mice as previously described [31].…”