Factors influencing the immune enhancement of intrapulmonary bactericidal mechanisms

Abstract

The effect of specific immunization on the antibacterial defense mechanisms of the murine lung was assessed against Streptococcus pneumoniae, Staphylococcus aureus, Staphylococcus aureus (Smith), Serratia marcescens, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa. Immunization by aerosol inhalation significantly enhanced the intrapulmonary killing of Pseudomonas aeruginosa and Proteus mirabilis but not the remaining organisms. With P. mirabilis, systemic immunization induced higher titers of specific serum agglutinins as compared with local respiratory tract immunization; however, local immunization was more effective in enhancing pulmonary bactericidal activity than was parenteral vaccination. Passive immunity against P. mirabilis or aerogenic challenge with preopsonized P. mirabilis significantly enhanced intrapulmonary killing of the homologous organism. With S. aureus, pulmonary bactericidal activity was not accelerated by aerosol challenge with the preopsonized organism, nor was it accelerated in passively immunized mice. These data demonstrate that the immune enhancement of pulmonary bactericidal activity is governed by the bacterium used for challenge and the route of immunization. The results further demonstrate that with P. mirabilis, antibody-mediated mechanisms are involved in the immune enhancement of pulmonary bactericidal activity.

The Regulation of Pulmonary Immunity

“…In contrast to the organisms discussed previously, previous immunization with S. aureus does not appear to enhance clearance or provide protective antibody in pulmonary infections ( Jakab, 1976). Recent studies suggest that the pulmonary clearance of this organism may be dependent on locally produced opsonins that enhance phagocytosis by AM.…”

Alveolar Macrophage Ingestion and Phagosome-Lysosome Fusion Defect Associated with Virus Pneumonia

“…In this study, the initial enhancement of phagocytic uptake by alveolar macrophages from animals with viral pneumonia reflects, in all probability, the additional defense capabilities re-cruited into the lungs by the inflammatory process. The subsequent enhancement is presumably associated with acquired immune mechanisms which augment macrophage phagocytic activity (7,10,12,15).…”

CLEARANCE OF BACTERIA FROM LUNGS OF MICE AFTER OPSONISING WITH IgG OR IgA

“…The lung differs importantly, however, from the peritoneum in being a secretory surface. Local immunity has been shown to exist in the lung (Jakab, 1976), and increased levels of s.IgA are produced by local immunisation (Reynolds and Thompson, 1973a). It remains to be proven whether the development of S.IgA antibodies is important for the effector mechanisms of local antibacterial immunity in the lung.…”

“…Very small particles of sizes 0-5 to 3 microns, bowever, are known to be able to penetrate to tbe respiratory bronchioles and alveoli (Stuart, 1973). Tbese particles, sucb as bacterial aerosols, are removed mainly by tbe alveolar macropbages (Creen and Kass, 1964) and tbeir removal may be enhanced by active or passive immunisation (Jakab, 1976).…”