LONG-TERM ANTIBODY-PRODUCTION AFTER LUNG IMMUNIZATION AND CHALLENGE -ROLE OF LUNG AND LYMPHOID-TISSUES

After localized lung immunization and challenge, antigen-specific anti body continues to be produced in the immunized lung lobes of dogs for years after the last antigen exposure. Lavage fluid from immunized lun g lobes contains significantly more antigen-specific antibody than lav age fluid from control lung lobes, and only cells from lung lobes expo sed to antigen produce antibody. Although cells lavaged from the lung produce antibody, it is possible that cells in the lung interstitium o r lymphoid tissues may be more important in long-term antibody product ion after lung immunization and challenge. The goal of this study was to compare the levels of antibody production by cells from dogs 2 yr a fter pulmonary immunization and challenge. Cells were evaluated from l ung lavage, lung tissue, tracheobronchial lymph nodes, and distant lym phoid tissues. The results showed that cells lavaged from lung lobes i mmunized and challenged with sheep red blood cells (SRBC) were produci ng anti-SRBC IgG antibody 2 yr after the last antigen challenge. Howev er, cells obtained by mincing tissues from immunized lung lobes were p roducing 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 p opliteal lymph nodes. These data suggest that most long-term antibody production in the lung is by cells from the lung interstitium, while c ells from control lung lobes and from draining or distant lymph nodes or spleen play little or no role in maintenance of antibody titers yea rs after the last exposure of the lungs to antigen.