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

Abstract

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 β-adrenoceptors in guinea-pig lung homogenates are described. Haemophilus influenzae, Streptococcus pneumoniae, Bordetella pertussis and Escherichia coli O 111B 4 induced a significant decrease of the number of β-adrenoceptors (by approximately 20%). Staphylococcus aureus, influenza A virus and Escherichia coli J 5 were not active. These data point to a common factor shared by gram-negative bacilli; i.e. endotoxin. Purified endotoxin of E. coli O 111B 4 also decreased the number of β-adrenoceptors, while E. coli J 5-LPS did not. This suggests that neural polysaccharides of bacterial cell walls, especially those in the ‘O’-antigenic side chain of gram-negative endotoxins may be responsible for the decrease of β-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 O 111B 4 LPS affected the number of β-adrenoceptors in the lung.