Long-term antibody production after lung immunization and challenge: role of lung and lymphoid tissues.

After localized lung immunization and challenge, antigen-specific antibody continues to be produced in the immunized lung lobes of dogs for years after the last antigen exposure. Lavage fluid from immunized lung lobes contains significantly more antigen-specific antibody than lavage fluid from control lung lobes, and only cells from lung lobes exposed to antigen produce antibody. Although cells lavaged from the lung produce antibody, it is possible that cells in the lung interstitium or lymphoid tissues may be more important in long-term antibody production after lung immunization and challenge. The goal of this study was to compare the levels of antibody production by cells from dogs 2 yr after pulmonary immunization and challenge. Cells were evaluated from lung lavage, lung tissue, tracheobronchial lymph nodes, and distant lymphoid tissues. The results showed that cells lavaged from lung lobes immunized and challenged with sheep red blood cells (SRBC) were producing anti-SRBC IgG antibody 2 yr after the last antigen challenge. However, cells obtained by mincing tissues from immunized lung lobes were producing significantly higher levels of antibody than lavage cells. In contrast, lavage or tissue cells obtained from the control lobes did not produce detectable antibody. Only a low level of anti-SRBC IgG was produced by cells from the tracheobronchial lymph nodes, and minimal antibody was produced by cells from blood, spleen, or mesenteric and popliteal lymph nodes.(ABSTRACT TRUNCATED AT 250 WORDS)