Final answer:
The statement that 'All immunogens are antigens but not all antigens are immunogens' is true. Immunogens are antigens that can activate an immune response, while other antigens may not trigger this response due to their insufficient size or complexity. B cells and T cells recognize antigens through specific receptors, and antigens play a pivotal role in both humoral and cellular immunity.
Step-by-step explanation:
The statement 'All immunogens are antigens but not all antigens are immunogens' is true. Immunogens are essentially a subset of antigens that are capable of provoking an immune response. While all immunogens are antigens because they can elicit this response, not all antigens meet the requirements to be considered immunogens due to factors such as molecular size, complexity, and class. For instance, a small molecule may function as an antigen based on its capacity to bind to antibodies, but if it is too small to initiate an immune response on its own, it is not an immunogen unless it is attached to a larger carrier molecule.
Antigens are molecules or molecular structures that are recognized by the immune system. While the term 'antigen' initially meant a substance that generates antibodies, it has since broadened to encompass substances that can stimulate cellular immunity as well. This role in stimulating cellular immunity is why they are sometimes more accurately referred to as immunogens. It's important to note that a single antigen molecule may have multiple epitopes, each being a target for a specific adaptive immune response induced by separate B cells or T cells.
Not every molecule is antigenic; it is the chemical structure of a substance that determines its potential to function as an antigen. B cells and T cells recognize antigens using their unique receptors; B-cell receptors (antibodies) and T-cell receptors respectively. B cells participate in the humoral immune response, which involves the production of antibodies that bind to antigens and remove them from the body. T cells, on the other hand, are part of the cellular immune response, where they help orchestrate the immune response and eliminate infected or dysfunctional cells.