Immune response of Brazilian children to a Neisseria meningitidis serogroup B outer membrane protein vaccine: comparison with efficacy.
Since 1986, serogroup B Neisseria meningitidis has caused approximately 80% of the meningococcal disease in Brazil. In 1988, an epidemic caused by N. meningitidis B:4:P1.15 was recognized in the greater São Paulo area of Brazil. The São Paulo state government decided to vaccinate children from 3 to 83 months of age with a vaccine consisting of serotype 4 outer membrane protein and group C meningococcal polysaccharide that was produced in Cuba. About 2.7 million children were vaccinated during two immunization campaigns conducted in 1989 and 1990. Because of this, a case-control study was designed to determine vaccine efficacy against group B meningococcal disease. The purpose of our study was to compare the antibody response with the protection from disease estimated from the case-control study. We measured the immune responses of vaccinees by enzyme-linked immunosorbent assay (ELISA), immunoblot, and bactericidal assay. The development of bactericidal antibodies was age dependent and in good agreement with the results of the case-control study. Only 40% of vaccinees showed fourfold or greater increases in bactericidal antibody titers after vaccination. A poor correlation between antibody levels detected by ELISA and those by bactericidal assay was found. Immunoblot analysis showed that about 50% of the serum samples with bactericidal titers higher than 1:4 were reactive with class 1 outer membrane protein. We conclude that the bactericidal assay is a good, laboratory-based, functional assay for the study of vaccine immunogenicity and that an effective solution to group B meningococcal disease remains to be demonstrated.
Milagres
L G
LG
Bacteriology Division, Adolfo Lutz Institute, São Paulo, Brazil.
Ramos
S R
SR
Sacchi
C T
CT
Melles
C E
CE
Vieira
V S
VS
Sato
H
H
Brito
G S
GS
Moraes
J C
JC
Frasch
C E
CE
D000907:Antibodies, Bacterial / Q000032:analysis*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D006801:Humans; D015151:Immunoblotting; D007223:Infant; D008589:Meningococcal Infections / Q000517:prevention & control; D009345:Neisseria meningitidis / Q000276:immunology*; D014611:Vaccination
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines