Immunity and infection is a UPF group

A number of surface receptors playing an inhibitory role have been identified in different leucocyte lineages; some belong to the Immunoglobulin superfamily (Ig-SF) whereas others are lectin-like molecules. Several of these receptors have been extensively characterized in Natural Killer cells and T lymphocytes.

The inhibitory mechanism involves cytoplasmic recruitment of SH2 domain-containing tyrosine phosphatases. These receptor families often include other members with a triggering function. Some receptors recognize well-defined molecules (MHC class I molecules, IgG, sialic acid); yet, the nature of ligands remains largely unknown. Analysis of the structure, genetic polymorphism, distribution and function of these receptor-ligand systems is revealing novel aspects on the regulation of the immune response, and may provide clues to understand the pathophysiology of immune disorders.