ABSTRACT
INTRODUCTION The way in which antigen preparations are presented to the immune system largely determines the magnitude and nature of the immune response they elicit. Vaccines based on one or more individual viral proteins or subunits are usually weakly immunogenic compared to live attenuated or inactivated whole virus vaccines (Morein et al., 1983; Morein and Simons, 1985), when administered without adjuvants. The use of adjuvants usually enhances the immunogenicity of protein preparations, resulting in higher titers of specific antibodies and T helper cell responses, but usually do not induce cytotoxic T cell (CTL) responses efficiently.
