The effect of splenectomy on the appearance of specific antibody-forming cells in lungs of dogs after intravenous immunization with sheep erythrocytes.

Effector cells of both T-lymphocyte-mediated and B-lymphocyte-mediated immunity can be induced experimentally to appear in the lung. It is not known whether such effector lymphocytes arise from precursor cells resident in the lung or if they are recruited from systemic sources. Previous studies demonstrated that IV administration of sheep erythrocytes to dogs consistently resulted in the appearance of specific antibody-forming cells, B-cell effectors, in lavage preparations obtained from the lung. In the present study, experiments were performed to determine the mechanism of appearance of effector B-cells in the lung after IV immunization. Control, sham-operated, and splenectomized dogs were immunized IV with 10(10) sheep erythrocytes. The concentrations of antibody-forming cells appearing in lymphocytes obtained from the lung and from peripheral blood were measured during both the primary and the secondary immune responses. Control and sham-operated dogs developed high concentrations of antibody-forming cells in blood 5 days after immunization, but splenectomized dogs did not. Antibody-forming cells consistently appeared in substantial numbers in lymphocytes obtained by lavage from lungs of control and sham-operated animals, however, they failed to appear in lungs of animals which had undergone splenectomy. Similar results were obtained both after primary and after secondary IV immunization. The data indicate that in this model, namely after IV immunization, with sheep erythrocytes, pulmonary antibody-forming cells or their precursors are derived from systemic sources (spleen) via the circulating blood. The observations provide strong in vivo evidence that lung antibody-forming cells are not generated locally after IV priming and boosting. The results of the present study relate directly to the mechanism of appearance of antibody-forming cells in lungs after IV, not local immunization. The study defines and documents one mechanism by which immune effector cells can appear in lung tissue.