Phase I clinical trial with a hexavalent PorA containing meningococcal outer membrane vesicle vaccine

Area of Science:

• * Vaccinology and Immunology
• * Microbiology and Infectious Diseases

Background:

• * Neisseria meningitidis poses a significant public health threat, with serogroup B being a major cause of invasive disease.
• * Outer membrane vesicle (OMV) vaccines are a promising strategy for meningococcal disease prevention.
• * PorA outer membrane proteins are key targets for developing effective meningococcal vaccines.

Purpose of the Study:

• * To evaluate the safety and immunogenicity of a novel hexavalent PorA OMV vaccine in adult volunteers.
• * To assess the bactericidal antibody response against specific PorA serosubtypes after vaccination.

Main Methods:

• * Preparation of a hexavalent PorA OMV vaccine from two production strains expressing specific class 1 outer membrane proteins.
• * Immunization of adult volunteers with two dosages (7.5 and 15 micrograms) of the vaccine.
• * Measurement of bactericidal antibody activity against six test strains expressing specific PorAs.

Main Results:

• * The hexavalent PorA OMV vaccine was found to be safe for use in adult volunteers.
• * Approximately 50% of volunteers receiving the higher dosage (15 micrograms) showed a fourfold increase in bactericidal antibody activity.
• * The observed bactericidal activity was specifically directed against the PorA proteins expressed by the vaccine.

Conclusions:

• * The hexavalent PorA OMV vaccine is safe and elicits a measurable immune response in adults.
• * The higher vaccine dosage demonstrated enhanced immunogenicity, suggesting a dose-dependent effect.
• * This vaccine holds potential for preventing invasive meningococcal disease caused by PorA-expressing serosubtypes.