Portuguese scientists study tick-borne bacteria

Study is a contribution to the development of new therapies against infectious diseases

A team of researchers from the Center for Neuroscience and Cell Biology of the University of Coimbra (CNC-UC) discovered how the rickettsia, a bacterium responsible for diseases like tick fever, manages to escape our immune system. This discovery opens the door to the development of new therapeutics against infectious diseases.

Contrary to what you might think, ticks are not responsible for tick fever, but the microorganisms that may be inside. THE rickettsiae is one of the bacteria that can be found in parasites, such as ticks, fleas or lice and that can be transmitted to humans through its bite.

Currently, climate change is favoring these parasites, as the increase in global temperature allows them to be active longer during the year. As a result, there is a greater geographic dispersion of parasites that can carry bacteria that are dangerous to human health.

In order to understand how these bacteria infect our organism, Pedro Curto and Isaura Simões, researchers at CNC-UC, studied a protein present on the surface of the bacteria rickettsiae, the APRc.

«After the bite of an infected tick, the rickettsiae enters the bloodstream where it will be exposed to all the machinery of our immune system. At this point, the bacteria's priority will be to protect itself and enter our cells at all costs, as its survival and capacity for infection depend on it», explains Pedro Curto, first author of the study.

“Infectious microorganisms have several escape mechanisms from our immune system. We already suspected that the APRc protein, present on the surface of Rickettsia, has an important role in the evasion of the bacteria, but in this study we found that, in addition, it also protects it, preventing the immune system from eliminating it», explains Isaura Simões, leader of the study.

This work, already published in the journal mBio, showed that the APRc protein can bind to antibodies present in the bloodstream, preventing the immune system from attacking and acting as a shield. It was also found that APRc offers extra protection to the bacteria against the bactericidal activity of proteins present in the serum (part of the blood).

"This is an important step in fundamental biology and a contribution to the development of new therapeutics against infectious diseases, which, unfortunately, are taking on an increasingly present role in today's world", stress the authors of the research.

The study was financed by the European Regional Development Fund (ERDF), through the COMPETE 2020 program – Competitiveness and Internationalization Operational Program –, and by national funds, through the Foundation for Science and Technology (FCT).

the scientific article is available by clicking here