What is the primary role of an antigen in the immune response?

The primary role of an antigen in the immune response is to provoke an immune response. Antigens are typically foreign substances such as proteins found on the surface of pathogens like bacteria and viruses, or they can even be components of non-infectious substances like pollen or toxic molecules. When the immune system detects these antigens, it triggers a series of responses designed to eliminate the threat.

This response involves various cells of the immune system, including B cells and T cells, which recognize and bind to the specific antigens. The binding leads to the activation of these cells, resulting in the production of antibodies (in the case of B cells) or the direct attack on infected cells (in the case of T cells). This is a crucial step in the immune process, as it allows the body to develop specific defenses against previously encountered pathogens and helps in building immunological memory.

While binding to antibodies and the destruction of pathogens are important aspects of the immune response, they are ultimately consequences of the initial provocation that the antigen causes. Promoting cell division, while relevant to immune cell expansion following activation, is not the primary function of an antigen itself. Thus, the key role of an antigen is to initiate the immune response rather than being directly involved in killing or