Identification of a 36-kDa fibronectin-binding protein expressed by a virulent variant of Leptospira interrogans serovar icterohaemorrhagiae

We investigated the ability of a virulent strain of Leptospira interrogans serovar icterohaemorrhagiae, its isogenic avirulent variant and a saprophyt ic strain to bind fibronectin using alkaline phosphatase-labelled fibronect in. A single 36-kDa fibronectin-binding protein was expressed only by the v irulent strain and was located in the outer sheath according to proteinase K treatment results. The interaction of this protein with fibronectin was s pecific and the region of fibronectin bound to this potential adhesin overl apped the gelatin-binding domain. The inability of a RGDS synthetic peptide to inhibit the binding of fibronectin indicated that the cell-binding doma in was not involved in this interaction. Considering the wide distribution of fibronectin within a host and the diversity of mammals involved in the e pidemiology of leptospirosis. its implication in the cell attachment proces s of virulent leptospires is coherent with the multiplicity of target cells . (C) 2000 Published by Elsevier Science B.V. All rights reserved.