T cell receptors are among the most important molecules in the immune system because of their role in recognizing the antigens that signal such threats as viruses and cancer. The receptors must also distinguish these threats from the body's own cells to avoid triggering an unwanted immune system response.
Recognition requires direct physical contact between the receptor and the antigen. Researchers attempting to understand this critical mechanism, therefore, have been studying such factors as the affinity for interaction between antigens and T cell receptors, how long those interactions last and how rapidly they occur. Information about these interactions has come mostly from studying receptor molecules removed from the outer membranes of T cells-the location where they normally operate.
]]>