Factors affecting Immunogenicity


An immunogen is a substance that can induce an immune response in a host organism. The immune response may involve the production of antibodies, the activation of T cells, or both. The immune response is specific to the immunogen and can provide protection against future exposure to the same or similar immunogens.

Not all substances are immunogenic, however. Some substances may be recognized as foreign by the host but fail to elicit a significant immune response. These substances are called antigens. Antigens can bind to antibodies or T cell receptors but cannot stimulate their production. Antigens may become immunogenic if they are conjugated with an immunogenic carrier molecule, such as a protein.

The ability of a substance to act as an immunogen depends on several factors, such as its foreignness, molecular size, chemical nature, heterogeneity, physical form, and susceptibility to antigen processing and presentation. These factors affect the recognition, uptake, processing, and presentation of the substance by the antigen-presenting cells (APCs), such as macrophages, dendritic cells, and B cells. APCs are responsible for capturing and displaying antigens to the T cells and B cells, which then initiate the adaptive immune response.

In this article, we will discuss how these factors affect the immunogenicity of a substance and provide some examples of immunogens and antigens. We will also explain some exceptions to these factors and how they relate to the concept of self and non-self in immunology.