Dot Blot Enzyme Immunoassay (EIA) Antibody Analysis Directed against Differentially Extracted Antigens Derived from Whole Cell Proteins of Neisseria meningitidis and Non-pathogenic Species in Meningococcal Vaccinated, Healthy and Other Disease Individuals

Abstract

Invasive meningococcal disease (IMD) is a rare but potentially life-threatening illness caused by Neisseria meningitidis invading the bloodstream. Early identification is crucial, as the disease progresses rapidly within the first few hours. Diagnosis relies on clinicians recognising common clinical symptoms since laboratory tests may not be rapid enough. Although commercial serological tests are available, they have drawbacks such as cost and the need for trained personnel. Most people have natural immunity to meningococcal disease due to consistent exposure to meningococci, other Neisseria species, and related genera that share common antigens. Researchers are exploring the mechanisms to develop more effective vaccines. Therefore, this study aimed to modify and evaluate Dot Blot EIA on nitrocellulose membrane of differentially extracted antigens derived from whole cell protein of N. meningitidis and non-pathogenic Neisseria species for serodiagnosis. Furthermore, this study aimed to investigate the humoral immune response patterns against meningococcal vaccinated, healthy and other diseases individuals. Additionally, investigate the potential for cross-reactivity with other Neisseria species or Moraxella genera. Analysis of the humoral immune response patterns revealed that most vaccinated individuals had IgG antibodies, as well as some presence of IgM and IgA antibodies. Although Men A and Men B of WCP and CSP did not show detectable antibodies in any of these types, their presence was revealed through the use of three different extraction methods. This demonstrates the sensitivity of our Dot Blot EIA assay. Conversely, the other disease group primarily exhibited IgM antibodies. Both the healthy group and individuals with other diseases may also have IgG and IgA antibodies present. Interestingly, some results from the healthy individuals showed a similar humoral immune response pattern as the vaccinated group. The presence of all antibody types in closely and distantly related species suggests the development of natural immunity. These commensal bacteria may share epitopes with pathogenic bacteria, leading to the production of cross-reactive antibodies and immune responses. Ultimately, further studies are necessary to fully validate and establish the potential of the Dot Blot EIA that may offer valuable insights into the immune response to meningococcal disease and vaccine effectiveness.