Receptor affinity purification of a lipid-binding adhesin from Haemophilus influenzae

Thirteen clinical strains of Haemophilus influenzae, including types b, d, and untypeable, in vitro specifically recognize phosphatidylethanolamine (PE), gangliotetraosylceramide, gangliotriosylceramide (Gg3), sulfatoxygalactosylceramide, and to a lesser extent sulfatoxygalactosylglycerol. A PE affinity matrix was used to purify an adhesin of approximately 46 kDa from both type b and untypeable H. influenzae. This adhesin was a potent inhibitor of H. influenzae Gg3 and PE binding in vitro, and polyclonal antibodies specific for this protein prevented the attachment of H. influenzae Gg3 and PE and cultured HEp-2 epithelial cells in vitro.