Growth of Haemophilus influenzae type b in continuous culture: Effect of dilution rate on outer-membrane protein and lipopolysaccharide expression

Haemophilus influenzae</it> type b (Hib) was grown in continuous culture under cystine-limitation between dilution rates (D) of 0.065–0.28 h−1. A similar outer-membrane protein profile, as adjudged by SDS-PAGE, was found at all dilution rates. However, a shift to a lipopolysaccharide structure with a greater electrophoretic mobility on SDS-PAGE with accompanying changes in monoclonal antibody reactivity was observed at D ≥ 0.15 h−1. Growth rate per se can affect the expression of outer-membrane components of Hib.