Bacteria-derived particles as adjuvants for non-replicating nasal vaccines

In attempts to mimic natural infections, vaccines consisting of microbial p articles may be delivered directly to mucosal surfaces. In this way, the mu cosal as well as the systemic immune systems can be activated. Even non-liv ing particles of bacterial origin have been shown to elicit strong immune r esponses when administered intranasally. However, some particles such as fo rmalin-inactivated influenza virus may need a mucosal adjuvant to be effect ive. The bacteria-derived particles seem to possess such an adjuvant activi ty when mixed with and given intranasally with the less immunogenic killed virus. Possibly, the bacterial particles facilitate uptake of the virus thr ough the mucosal membranes, although an additional influence on the immune response to the virus might be mediated in the lymphoid tissue below the mu cosal surface. Bacteria-derived particles in nasal vaccines may thus serve as an alternative adjuvant to derivatives of cholera toxin or the heat-labi le toxin from E. coli. (C) 2001 Elsevier Science B.V. All rights reserved.