Specificity of human bactericidal antibodies against PorA P1.7,16 induced with a hexavalent meningococcal outer membrane vesicle vaccine.
A set of isogenic strains was constructed from the meningococcal reference strain H44/76 (B:15:P1.7,16) which differed only in their outer membrane protein (OMP) compositions. First, three isogenic strains lacking the expression of either class 3 (PorB) or class 4 (RmpM) OMP or both were obtained. Second, three isogenic class 1 OMP loop-deficient strains of H44/76 lacking the predicted loop 1 or 4 or both of class 1 OMP (PorA) were obtained. Third, three isogenic class 1 OMP strains which differed by point mutations in the predicted loop 4 of subtype P1.16 were constructed. Strains were constructed through transformation with gene constructs made in Escherichia coli and their homologous recombination into the meningococcal chromosome. This study describes the contribution of one of the six class 1 OMPs, PorA P1.7,16, in the development of bactericidal antibodies after a single immunization of adult volunteers with 50 or 100 micrograms of protein within a hexavalent PorA outer membrane vesicle vaccine. PorA-, PorB-, and RpmM-deficient isogenic strains were used to define the human immune response against PorA. The loop-deficient isogenic strains were used to define the contribution of loops 1 and 4 of PorA in the development of bactericidal anti-PorA antibodies. The isogenic strains carrying a point mutation in loop 4 were used to study the cross-reactivity of the induced bactericidal antibodies against target strains showing microheterogeneity. The results indicate that a single immunization with the hexavalent PorA vaccine induced a dose-dependent bactericidal immune response, which is directed mainly against PorA. The epitope specificity of antibodies is directed mostly against loop 1, although loop 4 and as-yet-unidentified epitopes of PorA P1.7,16 are also involved.
van der Voort
E R
ER
Laboratory of Vaccine Development and Immune Mechanisms, National Institute of Public Health and the Environment, Bilthoven, The Netherlands. lvmervdv@rivm.nl
van der Ley
P
P
van der Biezen
J
J
George
S
S
Tunnela
O
O
van Dijken
H
H
Kuipers
B
B
Poolman
J
J
D000328:Adult; D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D000918:Antibody Specificity; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology; D001428:Bacterial Vaccines / Q000008:administration & dosage* / Q000235:genetics; D001483:Base Sequence; D001770:Blood Bactericidal Activity; D003429:Cross Reactions; D017931:DNA Primers / Q000235:genetics; D004306:Dose-Response Relationship, Immunologic; D000939:Epitopes / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007114:Immunization; D008585:Meningitis, Meningococcal / Q000276:immunology / Q000517:prevention & control; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000235:genetics / Q000276:immunology*; D010957:Plasmids / Q000235:genetics; D017354:Point Mutation; D018272:Porins / Q000235:genetics / Q000276:immunology*; D015183:Restriction Mapping; D014170:Transformation, Genetic; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D017931:DNA Primers; D000939:Epitopes; D018272:Porins; D014614:Vaccines, Synthetic; C057699:porin protein, Neisseria