Protein antigens are molecules that can elicit an immune response when introduced into an organism. These antigens are recognized by the immune system as foreign or non-self, leading to the activation of the immune system which may include the production of antibodies. In the context of immunology, antigens are typically proteins or peptides derived from proteins. Protein antigens have diverse applications in vaccines, diagnostic tests, laboratory research, immunotherapy, allergen detection, pathogen detection, and immunoassays. The specific and immunogenicity of our protein antigens make them valuable tools for understanding and manipulating the immune response in different contexts.