Aae Of Aggregatibacter actinomycetemcomitans Binds To Fibronectin And Laminin

Aggregatibacter actnimomycetemcomitans is a periodontal pathogen belonging to the HACEK group. Its adhesin Aae mediates adherence to epithelial and endothelial cells. Objectives: to test the hypothesis that Aae is able to bind to extracellular matrix (ECM) proteins, similar to other autotransporter proteins involved with adhesion. Methods: The gene aae of A. actinomycetemcomitans HK 1651 was cloned in pET-28 b (+), and expressed in E. coli. Recombinant Aae^His was purified and tested for its ability to bind to laminin and fibronectin. ECM proteins coated 96 well plates were incubated with different concentrations of purified Aae^His. Albumin coated wells and a nonbinding his-tagged protein were used as negative controls. After washings, the binding of Aae^His was detected by ELISA, using mouse anti-polyHistidine Ab and goat anti mouse IgG peroxidase Ab conjugate. Nonlinear regression analysis of the ELISA data was used to estimate the binding interactions between purified Aae and each of the ECM proteins. Results: Purified Aae bound to laminin and fibronectin in a dose dependent manner, but not the negative control albumin (ANOVA, Tukey, p<0.001). Conclusions: interaction between ECM and Aae suggested that this adhesin is important for the colonization of A.actinomycetemcomitans in inflamed subgingival sites where the organism encounter damaged epithelium and exposed basement membrane. (FAPESP 09/54178-0, 09/54849 ; CAPES).