Passive protection in the infant rat protection assay by sera taken before and after vaccination of teenagers with serogroup B meningococcal outer membrane vesicle vaccines.
From a previous published clinical trial among teenagers in Iceland [Perkins BA, Jonsdottir K, Briem H, Griffiths E, Plikaytis BD, Høiby EA, et al. J Infect Dis 1998;177:683--91], we evaluated a 25% stratified subset of sera, collected before vaccination and 6 weeks after the second vaccination with either the Norwegian (n=37) or the Cuban (n=35) serogroup B meningococcal outer membrane vesicle (OMV) vaccine or the control serogroup A/C capsular polysaccharide vaccine (n=20), for protective activity in an infant rat protection assay (IRPA). Protection was assessed with both the Norwegian (44/76-SL, B:15:P1.7,16:L3,7) and the Cuban (Cu 385, B:4:P1.19,15:L3,7) vaccine strain, and the results compared with serum bactericidal assay (SBA) titres and anti-OMV IgG antibody concentrations. An IRPA response was defined as a >or=10-fold rise in protective activity compared to pre-vaccination level. Forty-six percent (42/92) of the pre-vaccination sera showed protection with strain 44/76-SL compared to only 12% (11/92) with strain Cu 385. After the second dose, 22% (8/37) of those given the Norwegian vaccine showed IRPA responses with the homologous strain compared to 65% (24/37) in SBA. The corresponding numbers with the homologous strain for the Cuban vaccinees were 14% (5/35) and 29% (10/35), respectively. Among the controls, 15% (3/20) showed IRPA responses to 44/76-SL but none to Cu 385. Correlation between IRPA activity and SBA titres or anti-OMV IgG was low, especially for pre-vaccination sera against strain 44/76-SL. We conclude that the sensitivity of IRPA described herein may not be sufficient to evaluate serogroup B OMV vaccine responses from clinical samples.
Toropainen
Maija
M
Department of Vaccines, National Public Health Institute (KTL), Mannerheimintie 166, FIN-00300 Helsinki, Finland. maija.toropainen@ktl.fi
Saarinen
Leena
L
Wedege
Elisabeth
E
Bolstad
Karin
K
Mäkelä
P Helena
PH
Käyhty
Helena
H
D000293:Adolescent; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D002648:Child; D015169:Colony Count, Microbial; D003462:Cuba; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008589:Meningococcal Infections / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D009345:Neisseria meningitidis / Q000276:immunology; D009664:Norway; D051381:Rats
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D022401:Meningococcal Vaccines