Oral epithelial cells and immune responses towards oral bacteria
The role of oral epithelial cells in differential signaling for the development of immune responses towards oral bacteria
About the project
Undisturbed accumulation of bacteria on teeth induces soft tissue inflammation of the gingiva: gingivitis. The inflammation subsides after removal of the dental biofilm, without leaving permanent damage. The infection may, however, convert into periodontitis, a chronic inflammatory condition with permanent tooth attachment loss that can result in the expulsion of teeth. The disease is caused by pathogenic bacteria that attach to the teeth and outgrow the non-pathogenic bacteria of the normal oral flora. Treatment consists in professional removal of dental plaque and calculus, rigorous dental hygiene by the patient and sometimes the use of antibiotics. Gingivitis can be regarded as a well-regulated defense reaction, keeping the infection at bay without resulting in permanent tissue damage. In the case of periodontitis, there is an imbalance between the host and the parasites which requires that the immune system escalates the defense reaction and aims at tooth expulsion. T helper cells are crucial cells in the regulation of such immune reactions and are considered to be the “decision makers” that determine which type and grade of response the host has to develop. After activation, T helper cells develop into various subsets that either induce or inhibit different classes of defense reactions. Oral epithelial cells (OECs) are among the first cells that bacteria meet in the oral cavity. Besides forming a physical barrier, OECs can actively react to the presence of the bacteria, e.g. by secreting antibacterial peptides. The cells also produce and secrete mediators that have an effect on immune responses, of which the final outcome can be inflammation or tolerance. In this project, we study how differential responses are induced in OECs by bacteria.