Neisseria meningitidis RTX protein FrpC induces high levels of serum antibodies during invasive disease: polymorphism of frpC alleles and purification of recombinant FrpC.
The Neisseria meningitidis FAM20 strain secretes two proteins of unknown function, FrpA and FrpC, which contain typical RTX domains found in cytotoxins from other gram-negative pathogens. To evaluate whether the Frp proteins could be involved in meningococcal virulence, 65 isolates of all serogroups were screened by PCR for the presence of both frp genes. The frpA allele was, however, poorly conserved. A single strain harbored an frpA allele of the previously described size, while large insertions were detected in the frpA loci of 22 isolates (34%), and the 42 remaining isolates (65%) did not contain frpA at all. In contrast, frpC alleles, albeit of variable length, were detected in all invasive and most carrier strains. This suggests that meningococci may produce a family of FrpC proteins of various molecular masses. High levels of both immunoglobulin G (IgG) and IgA class antibodies recognizing recombinant FrpC were indeed detected in convalescent-phase sera of most patients at 2 and 4 to 5 weeks after the first symptoms of meningococcal disease. These results show that FrpC-like proteins are produced and may play a role in invasive meningococcal infections.
Osicka
R
R
Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the Academy of Sciences of the Czech Republic, Vídenská 1083, CZ-142 20 Prague 4, Czech Republic.
Kalmusová
J
J
Krízová
P
P
Sebo
P
P
D000483:Alleles; D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial / Q000097:blood*; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D003001:Cloning, Molecular; D003603:Cytotoxins; D006801:Humans; D033862:Iron-Binding Proteins; D008565:Membrane Proteins; D008589:Meningococcal Infections / Q000276:immunology* / Q000382:microbiology; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000276:immunology* / Q000378:metabolism*; D033902:Periplasmic Binding Proteins; D011110:Polymorphism, Genetic / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D003603:Cytotoxins; D033862:Iron-Binding Proteins; D008565:Membrane Proteins; D033902:Periplasmic Binding Proteins; D011994:Recombinant Proteins; C083530:frpC protein, Neisseria meningitidis