Abstract
Adhesion to host cells represents the first step in the infection process of B. henselae, a Gram negative, facultative intracellular zoonotic pathogen causing cat scratch disease, bacillary angiomatosis and other diseases in humans. The ability of B. henselae to cause vasculoproliferative disorders in humans is a unique and fascinating feature with potential medical implications. The trimeric autotransporter adhesin Bartonella adhesin A (BadA) of B. henselae represents one of the most important pathogenicity factors responsible for bacterial adhesion (e.g. to endothelial cells or matrix proteins) in static and dynamic infection models. BadA shows a remarkable modular construction and variations in length. Expression of BadA interferes with the function of other pathogenicity factors (e.g. the VirB/D4 type 4 secretion system). BadA-dependent angiogenic reprogramming is mediated by HIF-1 activation and inhibition of apoptosis in infected host cells. Angiogenic effects can be demonstrated when infecting human myeloid angiogenic progenitor cells with B. henselae. Analysis of the exact molecular functions of BadA will increase understanding how these pathogens adapt to their mammalian hosts.