Mucosal immunity in healthy adults after parenteral vaccination with outer-membrane vesicles from Neisseria meningitidis serogroup B.

Background: Nasopharyngeal carriage of meningococcus or related species leads to protective immunity in adolescence or early adulthood. This natural immunity is associated with mucosal and systemic T cell memory. Whether parenteral Neisseria meningitidis serogroup B (MenB) vaccination influences natural mucosal immunity is unknown.

Objectives: To determine whether parenteral MenB vaccination affects mucosal immunity in young adults and whether this immunity differs from that induced in the blood.

Methods: Otherwise healthy volunteers were immunized with MenB outer membrane vesicle vaccine before and after routine tonsillectomy. Mucosal and systemic immunity were assessed in 9 vaccinees and 12 unvaccinated control subjects by measuring mononuclear cell proliferation, cytokine production, Th1/Th2 surface marker expression, and antibody to MenB antigens.

Results: Parenteral vaccination induced a marked increase in systemic T cell immunity against MenB and a Th1 bias. In contrast, although mucosal T cell proliferation in response to MenB neither increased nor decreased following vaccination, mononuclear cell interferon gamma, interleukin (IL)-5, and IL-10 production increased, and the Th1/Th2 profile lost its Th1 bias.

Conclusions: Parenteral MenB vaccination selectively reprograms preexisting naturally acquired mucosal immunity. As new-generation protein-based MenB vaccine candidates undergo evaluation, the impact of these vaccines on mucosal immunity in both adults and children will need to be addressed.