Respiratory tract cell-mediated immunity: comparison of primary and secondary response

A secondary local and splenic cell-mediated immune response was observed and compared to the primary response. Previous studies have demonstrated cell-mediated immunity (CMI) by lymphocytes from bronchopulmonary washings and have shown that its appearance is to a large extent inedpendent of splenic CMI. This study evaluated the secondary as compared to the primary response, with respect to both cellular and humoral immune responses. Guinea pigs were immunized with influenza virus vaccine either nasally or parenterally, booster immunizations were given by the same route, and animals were killed at various times after immunization or booster. The inhibition of macrophage migration was used to assess CMI. As in previous studies, local application of antigen led to mainly local appearance of CMI, whereas parenteral immunization led to mainly systemic CMI. Both pulmonary and splenic lymphocytes showed an inhibition of macrophage migration that appeared 2 to 3 days sooner after the booster, as compared to the primary immunization. There was no evidence, however, for the earlier production or increased amount of antibody in the bronchial secretions in the boosted animals. The results suggest that pulmonary as well as splenic T lymphocytes exhibit memory, but that pulmonary B lymphocytes do not.