Bacterial cell wall components decrease the number of guinea-pig lung beta-adrenoceptors.

Infections of the deeper respiratory airways can contribute to the progression of chronic asthmatic bronchitis. In the present report a number of microorganisms affecting the number of beta-adrenoceptors in guinea-pig lung homogenates are described. Haemophilus influenzae, Streptococcus pneumoniae, Bordetella pertussis and Escherichia coli O111B4 induced a significant decrease of the number of beta-adrenoceptors (by approximately 20%). Staphylococcus aureus, influenza A virus and Escherichia coli J5 were not active. These data point to a common factor shared by gram-negative bacilli; i.e. endotoxin. Purified endotoxin of E. coli O111B4 also decreased the number of beta-adrenoceptors, while E. coli J5-LPS did not. This suggests that neutral polysaccharides of bacterial cell walls, especially those in the 'O'-antigenic side chain of gram-negative endotoxins may be responsible for the decrease of beta-adrenoceptor number and therefore contribute to the pathogenesis of chronic asthmatic bronchitis. Intact endotoxin seems to be necessary since neither the isolated lipid nor the polysaccharide part of E. coli O111B4 LPS affected the number of beta-adrenoceptors in the lung.