Immunologic Reactivity of the Lung

Abstract

Abstract The response of the guinea pig respiratory tract to locally administered antigen as well as the regulatory effect of antibody on this response was studied. The immune response of the respiratory tract to locally administered antigen was assessed by enumerating the absolute numbers of direct and indirect plaque-forming cells in the lung, hilar node, and spleen after intratracheal immunization with various doses of sheep red blood cells. This immune response of the lung could be localized primarily to the lung and hilar nodes by maintaining the dose of immunizing antigen below a critical level. The modulation of the pulmonary immune response by antibody was assessed by its effect on the numbers of plaque-forming cells in the lung and hilar nodes after immunization. IgG or IgM anti-SRBC antibody or anti-SRBC guinea pig immune serum were administered either locally (i.e., complexed to the SRBC at the time of immunization) or were given intraperitoneally 24 hr before immunization. High doses of each type of antibody, administered either locally or systemically, resulted in a delay in the peak plaque-forming response and a marked decrease in the absolute numbers of plaque-forming cells in the lung and hilar node after immunization. In contrast, progressively smaller amounts of each type of antibody resulted in a marked enhancement in the absolute numbers of plaque-forming cells in the lung and hilar node after immunization. Thus, although the lung can mount an immune response distinct from the systemic immune response, specific antibody present either locally or systemically may modulate this pulmonary immune response in a manner similar to the regulation of the systemic immune response.