Mucosal vaccines for Moraxella catarrhalis

摘要

Moraxella catarrhalis is an important human mucosal pathogen that causes otitis media in children and respiratory tract infections in adults. An optimal defense against mucosal pathogens would be mucosal vaccines. Since 1994, researchers have attempted to use different mucosal immunization regimes in mice such as oral, intra-Peyer's patches (IPP), intra-tracheal (IT), and intra-nasal (IN) administration either on killed cells or on outer membrane proteins. Among them, the only effective mucosal regimen turned out to be a combination of IPP and IT immunization. We investigated the mucosal immune response elicited by IN with a detoxified Iipooligosaccharide-cross-reactive mutant of diphtheria toxin (dLOS-CRM) conjugate. IN immunization with dLOS-CRM induced specific mucosal and systemic immunity and provided effective bacterial clearance in mouse lungs. To further enhance the mucosal immune response, intra-nasal-associated lymphoid tissue (NALT) administration of vaccines, was developed. In addition, a nasopharyngeal clearance mouse model is being tested. Although many vaccine candidates have been investigated by systemic immunization, mucosal vaccines for M. catarrhalis have been limited by the lack of appropriate adjuvants, vaccine delivery systems, and animal models. Future expectations are discussed.