Detection of IgG and IgM to meningococcal outer membrane proteins in relation to carriage of Neisseria meningitidis or Neisseria lactamica

Carriage of non-serogroupable Neisseria meningitidis or Neisseria lactamica induces antibodies protective against meningococcal disease. Antibodies di rected against outer membrane proteins are bactericidal and the serotype an d subtype outer membrane protein antigens are being examined for their valu e as vaccine candidates for serogroup B disease. The aim of this study was to examine the effect of carriage of these two Neisseria species among chil dren and young adults on induction of antibodies to outer membrane componen ts from strains causing disease in Greece. Among 53 patients with meningoco ccal disease, IgG or IgM antibodies were detected by ELISA in 9 of 13 (69%) from whom the bacteria were isolated and 27 of 40 (67%) who were culture-n egative. For military recruits (n = 604), the proportion of carriers of men ingococci with IgM or IgG to outer membrane proteins was higher than non-ca rriers, P<0.05 and P=0.000000, respectively. Among school children (n = 319 ), the proportion with IgM or IgG to outer membrane proteins for carriers o f meningococci was higher compared with non-carriers, P = 0.000000 and P = 0000043, respectively. Carriage of N. lactamica was not associated with the presence of either IgM or IgG to the outer membrane proteins in the childr en. The higher proportion of children (50%) with IgM to outer membrane prot eins compared with recruits (10%) might reflect more recent exposure and pr imary immune responses to the bacteria. The lack of association between ant ibodies to outer membrane proteins and carriage of N. lactamica could refle ct observations that the majority of N. lactamica isolates from Greece and other countries do not react with monoclonal typing reagents. Bactericidal antibodies to meningococci associated with high levels of IgG to N. lactami ca were found in a previous study; these are thought to be directed to anti gens other than outer membrane proteins or capsules and imply antigens such as lipo-oligosaccharide are involved in induction of antibodies cross-reac tive with meningococci. (C) 1999 Federation of European Microbiological Soc ieties. Published by Elsevier Science B.V. All rights reserved.