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

A meningococcal outer membrane vesicle (OMY) vaccine was prepared from two production strains designed to express three serosubtype-specific class I outer membrane proteins or PorA. The resulting hexavalent PorA OMV vaccine contained the serosubtypes P1.7,16; P1.5,2; P1.19,15; P1.7(h),4; P1.5(c),10; P1.12,13 and were used to immunize adult volunteers. A single immunization with two dosages, 7.5 and 15 mu g of the individual PorAs, was studied. The vaccine was considered safe for further use. Approximately half of the volunteers demonstrated a fourfold increase in bactericidal antibody activity against six test strains expressing the specific PorAs when given the higher dosage. This bactericidal activity was found to be directed against PorA. Copyright (C) 1996 Elsevier Science Ltd.