MENINGVAX / PROTECTIVE IMMUNITY / 017
Vaccine Immunology
Understanding how vaccination stimulates functional antibodies, activates complement-mediated bacterial killing, and establishes protective immune responses.
01 / PROTECTIVE MECHANISM
How bactericidal antibodies work
Antibodies recognizing surface structures on Neisseria meningitidis can activate the classical complement pathway. Complement activation may lead to bacterial membrane damage and killing.
Vaccine-induced antibodies bind bacterial surface antigens.
Bound antibodies can initiate complement activation.
The membrane attack complex can kill susceptible meningococci.
02 / FUNCTIONAL IMMUNOLOGY
Serum bactericidal antibody assays
The serum bactericidal antibody assay evaluates complement-dependent killing by antibodies in serum. It is an established immunological endpoint in meningococcal vaccine studies.
Human-complement SBA and rabbit-complement SBA are not interchangeable measurements. Their interpretation depends on assay design, serogroup, and the evidence supporting a particular threshold.
Does a strong antibody response always equal protection?
Not necessarily. Antibody specificity, functional activity, pathogen antigen expression, immune status, and the durability of responses all matter.
Peer-reviewed references
- Serologic correlates of protection for evaluating the response to meningococcal vaccines. PubMed ↗
- Bactericidal antibody is the immunologic surrogate of protection against meningococcal disease. PubMed ↗
- Serum bactericidal antibody assays: the role of complement in infection and immunity. PubMed ↗