Infection research: Antibodies prevent cell infection

Infections, especially those with highly resistant pathogens, pose a significant threat to human health. It is dangerous when pathogens manage to colonize the organism and subsequently cause severe infections. The first step in such an infection always consists of the pathogens attaching themselves to the host cells' surface. From here, the infections spread, resulting, for example, in infections of deeper tissue layers and organs.

一群科学家苏rrounding Prof. Volkhard Kempf from Frankfurt University Hospital's Institute of Microbiology and Hospital Hygiene has now succeeded in blocking this adhesion mechanism in a bacterium, thereby preventing the infection of host cells. For this purpose, the researchers examined the pathogenBartonella henselae,通常导致猫抓病。传播by cats, the disease mainly affects young children, whose symptoms include swollen and hardened lymph nodes around the site of infection -- usually following a scratch or bite injury caused by infected cats.

Bartonellabacteria infect so-called endothelial cells, which line the blood vessels. Via their surface proteinBartonellaadhesin A (BadA), they attach themselves to a protein (fibronectin) of the so-called "extracellular matrix," a network of protein fibers that lie on top of the endothelial cells.

To determine which parts of the BadA protein are important in the bacterial adhesion process, the researchers equippedBartonellabacteria with various genetically modified BadA variants, among others, and then analyzed the extent to which these variants were still able to bind fibronectin. Once it was clear which BadA segments were responsible for the binding, the team produced antibodies against them, using cell culture experiments to show for the first time that such antibodies can prevent infection by such bacteria.

Prof. Volkhard Kempf explains: "Bartonella henselaeis not a very dangerous pathogen, and in most cases, cat scratch disease does not require any specific medical treatment. However, for usBartonella henselaeis a very important model organism for far more dangerous pathogens such as不动杆菌baumannii, a serious pathogen that usually causes wound infection or pneumonia and often shows resistance to several last-choice antibiotics. The BadA protein ofBartonella henselaebelongs to the so-called 'trimeric autotransporter adhesins', which are also responsible for adhesion to human cells in不动杆菌and a number of other pathogens. A drug-induced blocking of these adhesins is therefore a promising novel and future approach to combat dangerous bacterial infections."