RESUMO
Infectious microorganisms are major sources of illness and death worldwide, and the leading cause of death in neonates. Effective vaccination of this age group is of particular importance. The lack of a response and greater susceptibility to tolerance are two major features that limit the effectiveness of vaccines in neonates. In this study we compare the cellular immune response generated following antigen injections at different times of life in newborn mice to that of adult mice. Adult and different age neonate mice were vaccinated with vesicular stomatitis virus [VSV]. One week after the last injection, cellular immunity was assayed on spleen cells that targeted EL4 infected cells using lactate dehydrogenase cytotoxicity assay. Antigen injection induced a decreased immune response in newborn mice compared with mice that had been immunized with subsequent injections. In the adult group, due to the evolution of the immune system, we observed a stronger immune response. Immunization of newborn mice may induce a reduced response when compared to adult vaccinations. However this can be corrected by the administration of additional booster doses