Lymphocyte homing receptors and the immune response in vivo

✍ Scribed by Irving L. Weissman

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 683 KB
• Volume: 5
• Category: Article
• ISSN: 0265-9247
• DOI: 10.1002/bies.950050305

✦ Synopsis

An important aspect of the developmental maturation of lymphocytes is their capacity to locate and enter lymphoid organs with great rapidity and specificity and to follow certain routes within these organs for the attainment of particular immunological capabilities. It is now known that this 'homing response' to lymphoid organs involves speclfic glycoprotein receptors on the lymphocyte cell surface. The biochemistry of these receptors and their significance in normal and pathological immune responses are discussed.

The Immune Response Occurs in vivo in Discrete Lymphoid

Organs

A key element to understanding the immune system is the fact that each lymphocyte is pre-committed to express on its surface only one immune specificity for its antigen receptor molecules; the frequency of any antigen receptorspecific lymphocyte is on the order of 1 in lo7 lymphocytes.1*2 The immune system must deal with the unpredictable. Therefore, the collection of antigen receptors must have the potential to fit any shape the universe can provide, and must at some point be able to distinguish shapes that are self from those that are non-self. Not only must the immune system have the competence to recognize all foreign shapes, but it must recognize those shapes as they are presented at any site of entry into the body. It appears that the immune system has solved this logistic problem by the device of giving mobility to the central elements of the immune response -the T and B lymphocytes. Mobility, however, is not enough, as the efficient interaction of lymphocyte subsets to generate an effective response requires a microenvironment of such complexity that only productive immune responses against non-self may ensue. The amount and quality of that immune response must be regulated sufficiently to wall-off and/or eliminate the antigenic pathogen, and then to cease lymphocyte proliferation when the external threat is