MODULATION OF THE ANTIGEN PRESENTATION ACTIVITY IN FOOT-AND-MOUTH-DISEASE VIRUS (FMDV) VACCINES BY 2 ADJUVANTS - AVRIDINE AND A WATER-SOLUBLE FRACTION OF MYCOBACTERIUM SP

We have previously demonstrated that the presence of the antigen prese nting cells (APC) is critical in the induction and maintenance of the immune response in animals infected or immunized with inactivated FMDV . The use of immunological adjuvants has been repeatedly shown to be e ssential for the improvement of the immunogenicity in FMDV vaccines. S pecifically, we have previously shown that the addition of the synthet ic lipoamide Avridine (AVR) or a water soluble fraction of Mycobacteri um sp. (WSF) significantly increased the immune response and protectio n against FMDV challenge. Here, we study the effect of these adjuvants on the induction of APC activity in mice immunized with inactivated F MDV. Both adjuvants were able to induce a long lasting antibody respon se which correlates with an efficient APC activity. Experiments using sequential cell transfers showed that the presence of the APC activity is not related with the efficiency of keeping free antigen in the vac cinated host. Interestingly, APC from animals immunized with AVR as ad juvant elicited virus neutralizing antibodies, while those APC obtaine d fr om donors vaccinated using WSF as adjuvant (or just an oil emulsi on) induced anti-FMDV detectable only by ELISA. The analysis of the an tibody response to a well studied synthetic peptide raised evidences t hat indicate that this difference could be explained by a differential presentation of viral B epitopes when different adjuvants were used. These results suggest that the induction of APC should be consider-ed as one of the critical factors in the process of improving the immunog enicity of experimental FMDV vaccines. (C) 1998 Elsevier Science Ltd. All rights reserved.