INFLUENZA-SPECIFIC IMMUNITY INDUCED BY RECOMBINANT LISTERIA-MONOCYTOGENES VACCINES

In this study, we evaluate two Listeria monocytogenes strains that exp ress influenza nucleoprotein (NP) sequences for their ability to prefe ct against challenge with influenza virus. The construction of one str ain, which expresses only the K-d restricted NP epitope (NP 147-155), is described in this study; the other strain, which expresses the full NP sequence in the form of a fusion protein, has been described previ ously. The ability of the two strains to present the K-d restricted NP epitope in vitro and induce NP-specific CTL in vivo is also described . Mice immunized by the intravenous route with either strain cleared a subsequent (3 weeks post-immunization) influenza virus infection more rapidly as indicated by reduced virus titers in the lungs 5 days afte r challenge. Efficacy of both recombinant L. monocytogenes strains as vaccines in this system was equivalent and equal to that of recombinan t vaccinia expressing NP. (C) 1997 Published by Elsevier Science Ltd.