Development of Immunization Protocols to Induce Integral (Systemic and Mucosal) Immune Response

Intramuscular (IM) vaccines, although effective in controlling infectious diseases, provide poor mucosal protection, where most of the pathogens gain access into the organism. Mucosal immunization (MI) may prevent the entrance of pathogens to the body interrupting their life cycle and making prophylactic measures more effective. However, direct MI may induce tolerance, which has been avoided using high dose of antigen (Ag), repeated immunization and toxic adjuvants, strategies not for use in human and veterinary medicine. Our group has studied immunization protocols that render integral (systemic and mucosal) immune response (IIR), paying attention to the age, route, site and number of immunizations. Using ovoalbumin (OVA) as Ag in our Vietnamese minipig animal model, before and after weaning, we studied parenteral and mucosal immunization routes at different sites, measuring serum and mucosal anti-OVA (IgG and IgA) responses by ELISA. Our results demonstrated differences between systemic and mucosal immune responses in unweaned animals, the induction of IIR in unweaned and weaned animals, a role for maternal antibodies in perinatal immunization (Figure) and also, the site of immunization had relevance in the effectiveness of the protocol. At the time, three immunizations are needed to induce IIR and a strong memory immune response after Ag boost. In summary, we developed a method to induce integral immunity without the use of high Ag dose, toxic adjuvants or multiple immunizations. Studies on the use of these protocols, with relevant Ags, are under way in our laboratory.

The financial support of CONACYT and the ICyTDF is acknowledged.