Superantigens and Biofilms in Sinus Diseases

Abstract

Superantigens (SAgs) are a group of microbial antigens that are differentiated by various properties from normal protein or peptide antigens. SAgs are very potent T-cell mitogens that can stimulate T lymphocytes to proliferate at lower concentrations (0.1 pg/mL) than conventional antigens, resulting in fever, shock, and even death. SAgs are defined as pathogenic agents of a wide variety of diseases, such as toxic shock syndrome, Kawasaki disease, acute rheumatoid fever, food poisoning, as well as many autoimmune disorders. SAgs are recognized by T-cell receptors (TCRs), particularly with TCR beta-chains (Vß), but also with Dß, Jß, Vα, and Jα, and are also presented to T cells with the aid of class II major histocompatibility complex (MHC) molecules. During presentation, these SAgs bind to amino acid residues outside the peptide-binding domain. The binding of the SAgs to the class II molecules on antigen-presenting cells (APCs) and to the TCRs produces a strong stimulatory signal. SAgs are divided into two groups: exogenous and endogenous. Biofilms are organized, heterogeneous bacterial communities embedded in a complex extracellular polymeric substance (EPS). Biofilm formation can be in vivo, in living cells, or in vitro, on non-living surfaces. Biofilm provides bacteria for protection against host defense, mechanical trauma, and temperature changes. Although increased biofilms have been demonstrated in patients with cardiorenal syndrome (CRS), there is still uncertainty about their role in etiopathogenesis, therefore more thorough investigation is necessary to prevent CRS. Understanding of the role of biofilms in the pathogenesis of CRS, resolving communication among them, developing existing treatments, and breaking antibiotic resistance will result in beneficial outcomes for both patients and physicians.