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[Common epitopes of protein antigens in Neisseria and Moraxella]
A V Goncharenko1, T N Filatova, L N Padiukov
1Mechnikov Research Institute for Vaccines and Sera, Moscow, Russia.
Abstract:
Cross reactions between N. meningitidis and M. catarrhalis proteins were studied with the use of a panel of monoclonal antibodies to M. catarrhalis protein antigens. All antigenic preparations under study were shown to give cross reactions between N. meningitidis serotype porin of 39 kD (strain B125) and M. catarrhalis proteins of 40-41 kD. These M. catarrhalis proteins belonged to main proteins of class F and had the function of porins in the cell. In addition, the epitope of 41-kD antigen, detected by monoclonal antibodies 3E10, is common for both N. meningitidis porin and N. meningitidis iron-regulated proteins of 70 and 50 kD. The epitope of M. catarrhalis protein of 67 kD, detected by monoclonal antibodies 1G6, is common for N. meningitidis porin and N. meningitidis iron-regulated proteins of 50 and 55 kD.
Insights
Cross-reactivity was observed between Neisseria meningitidis and Moraxella catarrhalis proteins. Specific epitopes on M. catarrhalis porins are shared with N. meningitidis porins and iron-regulated proteins, suggesting potential cross-immunity.
Area of Science:
- Microbiology
- Immunology
- Bacterial Pathogenesis
Background:
- Neisseria meningitidis and Moraxella catarrhalis are significant human pathogens.
- Understanding cross-reactivity between bacterial antigens is crucial for vaccine development and diagnostics.
- Monoclonal antibodies are valuable tools for identifying specific antigenic epitopes.
Purpose of the Study:
- To investigate cross-reactions between proteins of Neisseria meningitidis (N. meningitidis) and Moraxella catarrhalis (M. catarrhalis).
- To identify shared epitopes between N. meningitidis porins and M. catarrhalis proteins.
- To explore cross-reactivity with N. meningitidis iron-regulated proteins.
Main Methods:
- Utilized a panel of monoclonal antibodies specific to M. catarrhalis protein antigens.
- Analyzed antigenic preparations for cross-reactions using immunological assays.
- Characterized the molecular weights of reacting proteins (e.g., 39 kD, 40-41 kD, 67 kD).
Main Results:
- Cross-reactions were detected between N. meningitidis serotype porin (39 kD) and M. catarrhalis proteins (40-41 kD), identified as class F porins.
- A shared epitope was found between a 41-kD M. catarrhalis antigen and N. meningitidis porin and iron-regulated proteins (70 and 50 kD).
- Another shared epitope was identified on a 67-kD M. catarrhalis protein, common to N. meningitidis porin and iron-regulated proteins (50 and 55 kD).
Conclusions:
- Identified significant cross-reactivity between key outer membrane proteins of N. meningitidis and M. catarrhalis.
- Demonstrated shared epitopes on porins and iron-regulated proteins, indicating potential for cross-protective immune responses.
- Findings have implications for developing broader-spectrum vaccines or diagnostics targeting common bacterial antigens.