Published on November 30, 2020   38 min

Other Talks in the Series: The Immune System - key concepts and questions

Hello. I'm Anton van der Merwe from the University of Oxford, and I'm going to be talking about immunoreceptors.
This is an overview of my talk, starting with an introduction.
The challenge that leukocytes face is that they are the only cells that we have that throughout their lifetime migrate throughout the body, making contact with a very large variety of cells. What they are doing is trying to discriminate between the normal cells, which are the vast majority and the occasional abnormal cell and then selectively target their response to abnormal cells. Now another challenge is that what they're trying to detect are the presence of infecting microorganisms or cancer, and these are highly variable and rapidly evolving.
The process of leukocyte recognition which has to tackle this problem is mediated primarily by leukocytes cell surface receptors. These bind to soluble or surface associated ligands. The ligands include self molecules, as well as molecules derived from pathogens. There are over 300 receptors found on leukocytes in many different families. A typical leukocyte may express 100 or more receptors, and the single largest group of these receptors are termed immunoreceptors.
Immunoreceptors are also called non-catalytic tyrosine-phosphorylated receptors or NTRs for reasons which will become clear. They largely confine to leukocytes, so they've evolved essentially for leukocyte recognition. They have very diverse and rapidly evolving ectodomains, but their cytoplasmic domains are relatively conserved and link up to conserved signaling pathways. What these pathways are characterized by are that they have tyrosine- containing motifs which are phosphorylated by Src-family tyrosine kinases or SFKs. This phosphorylation is regulated by receptor protein tyrosine phosphatases, which are restricted to leukocytes.