Poster Presenter

Recent Advances In Detection And Functional Analysis Of Coxiella Burnetii - The Etiological Agent Of Q Fever
Toman R., Vadovic P., Betinova E., Hamadova M., Bartova K.
Slovakia

Coxiella burnetii causes Q fever, a severe infectious disease found worldwide. Its lipopolysaccharide (LPS I) contains two unusual sugars virenose (Vir) and dihydrohydroxystreptose (Strep) in the O-chain, mainly in terminal positions. In the later stages of infection or in persistent infection, a remarkable decrease in the serological activity of the LPS I was observed when the sugars were selectively released. This indicates that most late antibodies, so-called phase I antibodies are directed against the epitopes containing Vir and Strep. Recently, a unique monoclonal antibody (IgG2b subclass) has been generated that is highly specific for the presence of Vir in the LPS I. It can be used in future for rapid, sensitive and unambiguous detection of C. burnetii and differentiation of its isolates/variants.The O-specific chain containing both sugars is involved in the LPS I signaling through the TLR4/MD2 complex in contrast with the truncated (R) LPS II where the signaling proceeded through CR3. The structure of C. burnetii lipid A differed from those found for strongly endotoxic enterobacterial lipid A. This could be the reasons for the observed weak biological activities of the LPS I against host immune cells, thereby contributing to the persistent inflammatory reactions during infection.