Humoral and Cellular Immune Responses to Measles and Tetanus: The Importance of Elapsed Time Since Last Exposure and the Nature of the Antigen

Objective This study aims to assess the cellular and humoral immune response pre- and post-vaccine rechallenge in healthy adults with previous exposure to measles (virus or vaccine) and different time intervals since last tetanus vaccine. Methods Humoral immunity was tested by ELISA, and cellular immunity was tested by intracellular interferon gamma detection after in vitro stimulation with antigens. Results While cellular immunity was comparable among vaccinated individuals and those who had measles, higher antibody levels were found in those who had the disease in the past. Both antibodies and CD4⁺ T cell tetanus immune responses depended on elapsed time since last immunization. Following a vaccine booster, an increase in cellular immunity and antibodies was observed to both tetanus and measles. Measles humoral response was much more intense among individuals previously exposed to a wild virus. Conclusions In an era when natural boosters are less frequent, an immune surveillance might be necessary to investigate waning immunity as occurs for tetanus.