Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Temple University School of Medicine, Department of Medicine, Allergy and Immunology Section, University of Pennsylvania School of Medicine, Philadelphia Pennsylvania 19104
Lymphocytes from the mediastinal lymph nodes (draining the pulmonary phase of the infection), the hepatic lymph nodes (draining the hepatic phase of the infection), and the spleen of C57BL/6 mice exposed to Schistosoma mansoni were characterized relative to their capacity to interact with a soluble immunogen prepared from the adult worm (SWI). B or T RFC (rosette forming cells), RAFC (rosette-antibody forming cells), and PFC (plaque forming cells) were assayed. The RFC responses of the mediastinal and hepatic nodes were predominantly B cell in character and were maximal at that period which corresponded to the anatomic exposure which would be predicted from the migratory pattern of the parasite. High levels of T RFC and predominantly IgM B-responsive cells were generated in the mediastinal nodes during the presence of the schistosomulum in the lung parenchyma. Immunoglobulin-responsive (IgM > IgG > IgE) B cells were initially detected in the hepatic nodes during the lung-to-liver migration of the schistosomulum and its maturation to the adult form. However, elevated levels of T RFC and IgG > IgM ≥ IgE-responsive B cells were maximally present in the hepatic nodes during optimal egg production and egg-induced granuloma formation in the liver. In contrast to the responses of the lymph nodes, the splenic responses were predominantly T cell in nature for the first 8 weeks of infection. Splenic lymphocytes expressed a biphasic response, the first represented by T RFC and IgM-responsive B cells and coincided with the migration of the schistosomulum out of the lung and the second was also represented by T RFC but with predominance of IgG-responsive B cells and correlated with the production of eggs and maximal granuloma formation at the hepatic level.