Redesignation of a purported P1.15 subtype-specific meningococcal monoclonal antibody as a P1.19-specific reagent

Area of Science:

• Microbiology
• Immunology
• Molecular Biology

Background:

• Neisseria meningitidis expresses PorA outer membrane proteins, crucial for serogroup classification.
• PorA subtypes, like P1.15 and P1.19, are important targets for diagnostic and vaccine development.
• Monoclonal antibodies (mAbs) are key tools for identifying and differentiating PorA subtypes.

Purpose of the Study:

• To evaluate the specificity of two reference monoclonal antibodies against the meningococcal P1.15 PorA subtype.
• To clarify the antigenic targets of mAbs MN3C5C and 2-1-P1.15.
• To propose a reclassification for mAb 2-1-P1.15 based on its reactivity.

Main Methods:

• Serological testing of meningococcal isolates using mAbs MN3C5C and 2-1-P1.15.
• Biochemical analysis including cyanogen bromide cleavage of PorA protein.
• Peptide mapping and sequencing of porA gene regions.

Main Results:

• The reference mAbs MN3C5C and 2-1-P1.15 exhibited only partial concordance in recognizing meningococcal isolates.
• Chemical and genetic analyses confirmed that mAb 2-1-P1.15 specifically recognizes the P1.19 PorA subtype.
• mAb MN3C5C showed broader reactivity, consistent with targeting the P1.15 subtype.

Conclusions:

• The antibody 2-1-P1.15 is not specific for the P1.15 PorA subtype as initially assumed.
• Antibody 2-1-P1.15 should be redesignated as 2-1-P1.19 due to its P1.19 specificity.
• Accurate subtyping of PorA is essential for meningococcal research and diagnostics.