The Immunologic Basis for Effective Vaccines

Abstract

The protective immune response to a vaccine may be due to the presence of circulating antibody (humoral immunity), the actions of sensitized T-lymphocytes (cell-mediated immunity), the presence of antibody on mucosa surfaces (mucosal immunity); or a combination of these factors. When attenuated or killed viruses or bacteria are injected into an animal, they will induce an immunologic response. However, this immunologic response may not confer protective immunity because the vaccine may not have contained certain important antigens or it may not induce an immune response with the characteristics needed for protection. The immunologic basis for factors that influence the efficacy of vaccines will be discussed in this presentation. These factors include: the type of immune response induced, characteristics if viral and bacterial antigens, route and timing of vaccine administration, vaccine adjuvants, and the physiologic status of the animal receiving the vaccine.