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Human immune response to iron-repressible outer membrane proteins of Neisseria meningitidis
Abstract:
Neisseria meningitidis grown under iron-limiting conditions in vitro expresses additional iron-repressible outer membrane proteins (FeRPs). To see which FeRPs were expressed and immunogenic in human infection, we examined purified membranes from four meningococcal disease isolates with Western blotting of patient sera. Convalescent serum from each patient contained immunoglobulin G (IgG) and IgM antibodies against the homologous 70-kilodalton (kDa) FeRP and IgG antibody to the homologous 94-kDa FeRPs. Three other immunoreactive FeRPs were identified in two or more strains. Neither acute-phase sera nor pooled normal human sera contained appreciable levels of these antibodies. Antigenic cross-reactivity among FeRPs was suggested by the observation that the convalescent sera of two patients contained IgG antibodies reactive with the 70- and 94-kDa FeRPs and IgM antibodies reactive with the 70-kDa FeRPs from all four strains. Additionally, rabbit antiserum against the 70-kDa FeRP from one of these disease isolates contained IgG and IgM antibodies that reacted in Western blots with the 70-kDa FeRPs in all four strains. These results demonstrate that meningococcal FeRPs are expressed and immunogenic in vivo and that certain of these proteins are immunologically cross-reactive.
Insights
Neisseria meningitidis expresses iron-repressible outer membrane proteins (FeRPs) during infection. These FeRPs are immunogenic in humans, with antibodies recognizing multiple strains and suggesting cross-reactivity.
Area of Science:
- Microbiology
- Immunology
- Bacterial Pathogenesis
Background:
- Neisseria meningitidis, a significant human pathogen, expresses iron-repressible outer membrane proteins (FeRPs) under iron-limiting conditions.
- Understanding the in vivo expression and immunogenicity of these FeRPs is crucial for developing effective vaccines and treatments.
Purpose of the Study:
- To identify which FeRPs are expressed during human meningococcal infections.
- To determine the immunogenicity of these FeRPs in patients with meningococcal disease.
- To investigate potential antigenic cross-reactivity among expressed FeRPs.
Main Methods:
- Purified meningococcal membranes from four disease isolates were analyzed.
- Western blotting was performed using patient convalescent sera and rabbit antiserum.
- Antibody responses against specific FeRPs (70-kDa and 94-kDa) were assessed.
Main Results:
- Convalescent sera from patients contained IgG and IgM antibodies against 70-kDa FeRPs and IgG against 94-kDa FeRPs.
- Three additional immunoreactive FeRPs were detected in multiple strains.
- Antibodies showed cross-reactivity with FeRPs from different strains, and rabbit antiserum confirmed this cross-reactivity.
Conclusions:
- Meningococcal FeRPs are expressed and elicit an immune response in vivo during human infection.
- Certain FeRPs are immunogenic and antigenically cross-reactive, presenting potential targets for broad-spectrum meningococcal vaccines.