Immunogenicity

Abstract An antigen refers to a molecule that is able to bind to the cells of the immune system. If an antigen can also stimulate an immune response, it is termed an immunogen. Immunogenicity is a measure of this ability to activate the immune response: that is, the B and T cells underlying humoral and cell‐mediated immunity. Understanding the concept of immunogenicity is therefore vital in understanding the field of immunology as a whole. The determinants of immunogenicity are complex, but much research has been conducted in this area in the context of vaccination and protein therapeutics, where understanding immunogenicity is of key clinical significance. While obtaining accurate measures of immunogenicity is difficult, a range of techniques to both predict the immunogenicity of a substance and to measure immunogenicity based on B and T cell activation have been developed. Key Concepts Immunogenicity is defined as the ability of a substance to elicit an adaptive immune response. The immunogenicity of a substance depends on multiple factors relating to the properties of the substance itself, the biological system, and how the substance is delivered to the biological system. Immunogenicity is necessary for our body to respond to and destroy pathogens, as well as to remove tumourogenic and dying cells. Understanding immunogenicity is important for pharmaceutical development, where it is sometimes necessary to either increase (vaccination) or decrease (protein therapeutics) the immunogenicity of a product. Experimental model systems, and more recently, computational tools, are being developed to predict immunogenicity. Immunogenicity can be measured empirically by assessing the numbers of activated T or B cells, or antibody levels during a response to the substance.