HUMAN LACTOFERRIN RECEPTOR ACTIVITY IN NONENCAPSULATED HAEMOPHILUS-INFLUENZAE

Since the ability of bacteria to compete with lactoferrin for iron con tributes to the pathogenesis of mucosal infections, the presence of la ctoferrin receptor activity in non-encapsulated Haemophilus influenzae was investigated. The growth of 18 H. influenzae isolates from the sp utum samples of chronic bronchitis patients and of six of seven H. inf luenzae throat isolates from healthy adults was stimulated by iron sat urated human lactoferrin. Apo-lactoferrin did not stimulate the growth of H. influenzae. Human lactoferrin binding to iron limited bacteria was detected for 16 H. influenzae strains from chronic bronchitis pati ents and for five of seven isolates from healthy adults. We conclude t hat the majority of H. influenzae isolates tested bind human lactoferr in and that the iron from lactoferrin is used for growth.