The immunomodulatory properties of the CD5 lymphocyte receptor in health and disease

CD5 is a scavenger-like receptor expressed in association with the antigen-specific receptors on T and B-1a lymphocytes. Recent studies reveal a broader biology for CD5 that includes its role as regulator of cell death and as a receptor for pathogen-associated molecular patterns, in addition to its previously described function as an inhibitory receptor. These findings shed new light into the mechanistic role of CD5 in leukemias and effector cells to exogenous (infectious) or endogenous (autoimmune, tumoral) antigens. The newly identified properties make this receptor a potential candidate to be targeted for therapeutic intervention as well as immune modulation. This review describes the current knowledge on the function of CD5 as an immunomodulatory receptor both in health and in disease.

► CD5 qualitatively and quantitatively modulates T-cell and B-cell response to antigen.
► CD5 transduces prosurvival signals in addition to and independent from its inhibitory activity.
► CD5 regulates generation, activity and survival of Treg cells and Breg homeostasis.
► CD5 is a receptor for pathogen-associated molecular patterns of fungal origin.
► Use of sCD5 as decoy receptor is therapeutically beneficial to treat autoimmunity and fungal sepsis.