Expression of an inaccessible P1.7 subtype epitope on meningococcal class 1 proteins

J Med Microbiol. 1993 Jan;38(1):23-8. doi: 10.1099/00222615-38-1-23.


Dot-blot analysis of whole-cell suspensions of meningococci showed that 81% of B:15:P1.16 strains from patients reacted with a monoclonal antibody (MAb) against subtype P1.7. The remaining strains, which did not react on dot-blots or in ELISA, demonstrated the P1.7 subtype epitope on immunoblots after denaturation of the cells with sodium dodecyl sulphate. The monomeric class 1 proteins of the two P1.16 subtype variants had slightly different mol. wts, but bound the P1.7 antibody equally well. These results were explained by a deletion of three codons in the gene encoding the first variable region of the P1.16 class 1 protein. The deletion accounted for the non-exposure of the P1.7 epitope on native cells. Other patient strains, with subtypes P1.3, P1.9 or without any known subtype, also showed a binding site for the P1.7 MAb, which became available only after denaturation. Demonstration of inaccessible epitopes may have consequences for subtype designations and vaccine development.

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Monoclonal / immunology
  • Antibody Specificity
  • Antigens, Bacterial / analysis*
  • Antigens, Bacterial / chemistry
  • Bacterial Outer Membrane Proteins / chemistry
  • Bacterial Outer Membrane Proteins / genetics*
  • Bacterial Outer Membrane Proteins / immunology
  • Base Sequence
  • DNA, Bacterial / chemistry
  • Enzyme-Linked Immunosorbent Assay
  • Epitopes / analysis
  • Epitopes / chemistry
  • Gene Expression Regulation, Bacterial*
  • Genotype
  • Humans
  • Immunoblotting
  • Meningococcal Infections / microbiology*
  • Molecular Sequence Data
  • Neisseria meningitidis / classification
  • Neisseria meningitidis / immunology*
  • Polymerase Chain Reaction
  • Porins*
  • Serotyping


  • Antibodies, Monoclonal
  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • DNA, Bacterial
  • Epitopes
  • Porins
  • porin protein, Neisseria