Effect of oral rotavirus/iscom vaccines on immune responses in gnotobioticlambs

A comparison of the effect on the immune responses in gnotobiotic lambs was made between an iscom vaccine prepared from recombinant rotavirus VP6 prot ein, an inactivated rotavirus/iscom-matrix vaccine and a vaccine comprising inactivated rotavirus alone. All three vaccines induced immunological prim ing and some degree of protection was observed after a single oral dose. Ho wever, different immune responses were induced in response to a virulent in fection. The group vaccinated with the rotavirus/iscom-matrix vaccine showe d a Th2-like response characterised by rotavirus-specific antibodies and a down-regulation of IFN gamma in jejunal Peyer's patches. Both Th1-like and Th2-like immune responses were induced in the group receiving the VP6 vacci ne as seen by significantly increased expressions of IFN gamma and IL-6 in the jejunal Peyer's patch together with an increased percentage of CD8(+) T cells in the intestine and rotavirus-specific antibodies at mucosal surfac es. Iscom vaccines given orally have the ability to induce both Th1-like an d Th2-like immune responses in a ruminant model. (C) 1999 Elsevier Science B.V. All rights reserved.