Methods to evaluate the effects of toxic materials deposited in the lung on immunity in lung-associated lymph nodes

Intratracheal instillation of sheep red blood cells (SRBC) induced a primary immune response in lung-associated lymph nodes of Chinese hamsters and Fischer-344 rats. Few or no anti-SRBC antibody forming cells (AFC) were found in the spleen or cervical lymph nodes after intratracheal immunization. The number of AFC was significantly suppressed in the lung-associated lymph nodes from hamsters exposed by inhalation of 239PuO2 and in rats exposed by intratracheal instillation of benzo(a)pyrene (BaP). Although the immunologic function of the lung-associated lymph nodes was suppressed by 239PuO2 and BaP exposure, there was no observable increase in the number of AFC in distant lymphoid tissues. These data indicate that damage to lung cells and/or cells in lung-associated lymph nodes can suppress immunity induced by deposition of antigen in the lung. Even though lung-associated lymph nodes in exposed animals contained lower numbers of AFC, antigen instilled into the lungs of exposed animals did not significatnly translocate to distant lymphoid tissues. This indicates that the antigen filtering capacity of the lung-associated lymph nodes was not altered.