Haemophilus influenzae and the beta-adrenergic system: a review

Haemophilus influenzae is a bacterium that often can be isolated from the deeper respiratory airways of patients with chronic asthmatic bronchitis. In the present study the effects of H. influenzae vaccination on guinea pig pulmonary beta-adrenoceptor number and function (in vitro and in vivo) have been evaluated. Functioning of beta-adrenoceptors is determined by measuring the beta-mimetic effect of isoprenaline on the inhibition of anaphylactic mediator release and isolated tracheal strip relaxation. The number of beta-adrenoceptor binding sites was measured by means of a 3H-dihydroalprenolol binding assay. Also the mechanism of action underlying the changes in beta-adrenoceptor functioning was evaluated. Furthermore, it was established that the effect on the beta-adrenoceptor system was not specific for H. influenzae and that other respiratory pathogens were also biologically active in this respect.