Induction of immune responses in newborn lambs following enteric immunization with a human adenovirus vaccine vector

We investigated the antigen-specific mucosal and systemic immune responses of newborn lambs following enteric immunization, targeting jejunal Peyer's patches with a human adenovirus vector that expressed the glycoprotein D (g D) of bovine herpesvirus-1. Both humoral and cell-mediated go-specific muco sal immune responses were detected in newborn lambs (1-4 days old) after a single immunization and these responses were qualitatively and quantitative ly similar to those detected in 5-6-week-old lambs. Passively transferred g o-specific maternal antibody did not significantly alter either mucosal or systemic gD-specific immune responses. Furthermore, enteric immunization of newborn lambs primed mucosal immune responses in the lungs. These observat ions confirmed that gut-associated lymphoid tissue of a newborn ruminant is immune competent and that enteric immunization may be an effective approac h for the induction of both mucosal and systemic immune responses in the ne onate. (C) 2000 Elsevier Science Ltd. All rights reserved.