Nontypeable Haemophilus influenzae (NTHI) lipooligosaccharide htrB mutants exhibited greater than 45-fold-increased sensitivity to human β-defensin 2 (HBD-2) compared to the wild type. Complementation by htrB in trans to acylation competence reversed this increased sensitivity. In contrast, NTHI was more susceptible to HBD-3 and showed no changes in sensitivity as a result of lipooligosaccharide mutations in oligosaccharide and lipid A biosynthesis genes.
