Structural Assessment of Major Outer Membrane Protein (MOMP)-Derived Vaccine Antigens and Immunological Profiling in Mice with Different Genetic Backgrounds.

() is the most common cause of bacterial sexually transmitted infections (STIs) worldwide. infections are often asymptomatic in women, leading to severe reproductive tract sequelae. Development of a vaccine against is crucial. The major outer membrane protein (MOMP) is a prime vaccine antigen candidate, and it can elicit both neutralizing antibodies and protective CD4+ T cell responses. We have previously designed chimeric antigens composed of immunogenic variable regions (VDs) and conserved regions (CDs) of MOMP from () expressed into a carrier protein (PorB), and we have shown that these were protective in a mouse model of respiratory infection. Here, we generated corresponding constructs based on MOMP from serovar F. Preliminary structure analysis of the three antigens, PorB/VD1-3, PorB/VD1-4 and PorB/VD1-2-4, showed that they retained structure features consistent with those of PorB. The antigens induced robust humoral and cellular responses in mice with different genetic backgrounds. The antibodies were cross-reactive against but only anti-PorB/VD1-4 and anti-PorB/VD1-2-4 IgG antibodies were neutralizing, likely due to the antigen specificity. The cellular responses included proliferation in vitro and production of IFN-γ by splenocytes following re-stimulation. Our results support further investigation of the PorB/VD antigens as potential protective candidates for a subunit vaccine.