Treponema denticola major outer sheath protein (Msp) inhibits neutrophil chemotaxis in
vitro, but key regulatory mechanisms have not been identified. Because the Rac small
GTPases regulate directional migration in response to chemoattractants, the objective was
to analyse the effects of Msp on formyl‐methionyl‐leucyl‐phenylalanine (fMLP)‐mediated
neutrophil polarization and Rac activation in murine neutrophils. Msp pretreatment of
neutrophils inhibited both polarization and chemotactic migration in response to fMLP …

Bacterial infections contribfute to the chronicity of connective tissue lesions in part by
perturbing extracellular matrix remodelling processes. We examined a novel mechanism by
which the major outer sheath protein (Msp) of the spirochaete Treponema denticola disrupts
matrix remodelling mediated by intracellular digestion of collagen. The initial collagen-
binding step of phagocytosis was examined in human gingival fibroblasts and Rat-2
fibroblasts. Cells were pretreated with Msp or vehicle, and binding of collagen-coated beads …