Mucosal approaches in Neisseria Vaccinology

Meningococcal B strains accounts for some 72% and 28% of meningococcal diseases in infants and toddlers in Europe and the USA, respectively. Nevertheless, meningococcal diseases are rare in Cuba owing to the wide spread program on antimeningococcal vaccination in the country. Finlay Institute is one of the pioneering organizations in Neisseria Vaccinology mainly by its contribution to N. meningitidis serogroup B outer membrane-based bivalent vaccine, VA-MENGOC-BC™. This vaccine was given intramuscularly in more than 60 million doses corresponding 10.7 millions of them to Cuban young adults, children, and infants. However, most dangerous or commensally Neisseria strains enter and establish in the mucosa, where the secretory (S) IgA is the main specific guardian and is mainly induced by mucosal routes. However, few mucosal vaccines exist principally due to the absent of mucosal adjuvants. We develop a Finlay Adjuvant (AF) platform based in outer membrane vesicles (Proteoliposome, PL) and its derivate Cochleate (Co). AFPL1 derived from serogroup B N. meningitidis is a potent Th1/CTL driving parenteral adjuvant. AFCo1 is a potent mucosal adjuvant. Therefore, we sought to go deeper in the possible mucosal cross recognition between N. meningitidis serogroups and Neisseria species and explore a concurrent mucosal and parenteral immunization strategy (SinTimVaS) in order to develop suitable mucosal vaccines. Experiments were conducted in Balb/c or C57Bl6 mice with mucosal and systemic immunization using AFCo1 and AFPL1. Human sera and saliva were also analyzed for cross cognition. Mucosal cross recognition at SIgA level in human saliva between N. meningitidis serogroups B, A, C, Y, and W135 were observed. This SIgA cross recognition response was also observed between pathogenic (N. meningitidis serogroup B, N. gonorrhoeae) and non-pathogenic strains (N. flava, N. lactamica). The possible influence of meningococcal vaccination against Gonorrhea was also explored. A proprietary Single Time Vaccination Strategy combining simultaneous mucosal and parenteral doses was developed. N. meningitidis and N. gonorrhoeae show significant cross immune response, and mucosal immunization with AFCo1 to obtain immunity against both strains may be a useful strategy to combat both infections in humans. Single Time Vaccination Strategy could be important to increased human vaccination coverage and herd immunity protecting both systemic and mucosal environments.