Answer: If the T cell receptor binds weakly, the cell is released from the thymus and travels to a secondary lymphoid organ (e.g., lymph nodes), where it rests until called upon later in life.
Step-by-step explanation:
When T cells are developing in the thymus, they undergo a process of positive and negative selection to ensure they can recognize antigens presented by the major histocompatibility complex (MHC) molecules. If a T cell receptor (TCR) binds weakly to self-MHC molecules or fails to recognize any MHC molecules at all, it is considered non-functional or potentially harmful to the body. In such cases, the T cell is eliminated through apoptosis (programmed cell death).
However, if the TCR binds weakly to self-MHC molecules but does not cause harm, it is released from the thymus as a mature T cell. These T cells then migrate to secondary lymphoid organs such as lymph nodes, where they rest until they are activated by encountering specific antigens later in life.
The secondary lymphoid organs serve as sites for immune cell interaction and immune response activation. In lymph nodes, for example, T cells can encounter antigen-presenting cells (APCs) that have captured antigens from pathogens. This interaction can lead to T cell activation and subsequent immune responses to fight off infections.
In summary, T cells with weak binding to self-MHC molecules are released from the thymus and travel to secondary lymphoid organs, such as lymph nodes, where they rest until called upon later in life when they encounter specific antigens and are activated to mount an immune response.