Splenic regulation of the murine pulmonary lymph node response.

Exposure to intratracheal immunization and aerosolization with soluble antigen plus murmayl-dipeptide (MDP) induces the development of plaque-forming cells in the pulmonary draining lymph nodes of two of three inbred mouse strains. Splenectomy before immunization led to a heightened plaque-forming cell response in the two responder mouse strains. Adoptive transfer of spleen cells from one strain exposed to sperm whale myoglobin via the respiratory tract revealed the presence of antigen-specific suppressor cells. These observations suggest that the spleen may play a role in the down-regulation of an immune response elicited in the pulmonary draining lymph nodes by exposure of the respiratory tract to soluble antigens plus MDP.