Structure of γδ T cell receptors and their recognition of non-peptide antigens

Abstract

The γδ T cell receptors (TCRs) and αβ TCRs are similar in both sequence and structure; however, γδ + and αβ + T cells are not merely similar lymphocytes with subtly different receptors. These cell types differ in several ways, including the types of antigens recognized, the mechanism of antigen presentation and recognition and the mechanism and kinetics of downstream signaling events. γδ TCRs can directly recognize antigens in the form of intact proteins or non-peptidic compounds, unlike αβ TCRs which recognize peptide antigens bound to major histocompatibility complex molecules (MHC). One of the major classes of human γδ + T cells expresses Vγ9Vδ2 TCRs which recognize pyrophosphomonoester, alkylamine and aminobisphosphonate antigens. This review focuses on the recently determined structure of a Vγ9Vδ2 TCR, with emphasis on antigen recognition and receptor signaling.