CD36 family members are TCR-independent ligands for CD1 antigen-presenting molecules

Abstract

CD1c presents lipid-based antigens to CD1c-restricted T cells which are thought to be a major component of the human T cell pool. The study of CD1c-restricted T cells, however, is hampered by the presence of an abundantly expressed CD1c-binding partner on blood cells distinct to the T cell receptor (TCR), confounding analysis of TCR-mediated CD1c tetramer staining. Here, we identify the CD36 family (CD36, CD36-L1 and CD36-L2) as novel ligands for CD1c, CD1b and CD1d proteins, and show that CD36 is the receptor responsible for non-TCR-mediated CD1c tetramer staining of blood cells. Moreover, CD36-blockade enables tetramer-based identification of CD1c-restricted T cells and clarifies identification of CD1b- and CD1d-restricted T cells. We use this technique to characterise CD1c-restricted T cells ex vivo and show diverse phenotypic features, TCR repertoire and antigen-specific subsets. Accordingly, this work will enable further studies into the biology of CD1 and human CD1-restricted T cells.

A novel α/β T-cell subpopulation defined by recognition of EPCR

“…In this sense, a high proportion of the CD3 - ST + cells (59-82%) expressed CD56 on their membrane (Fig. 2B, left panel) but lacked TCR expression, thus corroborating the presence of TCR-independent surface ligands for CD1d 18 and EPCR in NK cells. Taken together, these results indicate the presence of self-recognizing endo-EPCR-specific α/β T lymphocytes in the human PBMC pool.…”