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Antigens that are similar in apparent molecular weight to gonococcal outer membrane protein III
Abstract:
Two immunoglobulin G monoclonal antibodies (MAbs) were produced by using purified outer membranes and whole gonococci as immunogens. These MAbs recognized antigens with similar apparent sizes (30 to 31.5 kilodaltons [kDa]) in several pathogenic and nonpathogenic neisseriae. In gonococci, these 30- to 31.5-kDa components, although similar in subunit size to outer membrane protein III (P.III), are distinct due to their differences in electrophoretic migration-modification by 2-mercaptoethanol and their cellular location. The two 30- to 31.5-kDa moieties are denoted by MAb2 and MAb3, respectively, by which they are identified. The differentiating characteristic of these three antigens (P.III, MAb2, MAb3) is their change or lack of change in electrophoretic mobility in the presence versus absence of 2-mercaptoethanol; P.III migrates less rapidly, MAb2 does not change, and MAb3 migrates more rapidly. Both the epitopes that were reactive with MAb2 and MAb3 were resistant to proteolytic treatment of intact gonococci; neither epitope was detected on whole, unfixed gonococci by immunofluorescence. Both MAb2 and MAb3 epitopes were represented uniformly among pathogenic neisseriae (except group Z meningococci) and less regularly among nonpathogenic neisseriae.
Insights
Two new monoclonal antibodies (MAbs) identified distinct 30-31.5 kDa antigens in Neisseria species. These novel gonococcal antigens show unique electrophoretic properties and varied distribution across pathogenic and nonpathogenic strains.
Area of Science:
- Immunology
- Microbiology
- Bacteriology
Background:
- Neisseria species, including pathogenic Neisseria gonorrhoeae, possess diverse outer membrane proteins crucial for their survival and virulence.
- Characterizing these surface antigens is vital for understanding bacterial pathogenesis and developing diagnostic or therapeutic strategies.
Purpose of the Study:
- To produce and characterize novel monoclonal antibodies (MAbs) targeting specific antigens on Neisseria outer membranes.
- To investigate the size, properties, and distribution of these targeted antigens in various Neisseria species.
Main Methods:
- Production of two immunoglobulin G monoclonal antibodies (MAbs) using purified outer membranes and whole gonococci.
- Analysis of antigen recognition by MAbs, including apparent size determination (30-31.5 kDa) and electrophoretic migration analysis with and without 2-mercaptoethanol.
- Assessment of antigen resistance to proteolytic treatment and detection on intact bacteria via immunofluorescence.
Main Results:
- Two MAbs, designated MAb2 and MAb3, recognized distinct antigens of 30-31.5 kDa in Neisseria.
- These antigens, while similar in size to outer membrane protein III (P.III), differed in electrophoretic mobility and response to 2-mercaptoethanol.
- MAb2 and MAb3 epitopes were resistant to proteolysis and not detected on the surface of intact gonococci by immunofluorescence.
- The recognized epitopes were consistently found in pathogenic Neisseria (excluding group Z meningococci) but less regularly in nonpathogenic strains.
Conclusions:
- Novel monoclonal antibodies (MAb2, MAb3) identify unique 30-31.5 kDa antigens in Neisseria, distinct from outer membrane protein III.
- These antigens exhibit differential electrophoretic properties and variable distribution, suggesting potential roles in Neisseria classification or pathogenesis.
- The cell-associated, non-surface-exposed nature of these epitopes warrants further investigation into their function and significance.