DX5/CD49b-positive T cells are not synonymous with CD1d-dependent NKT cells

Abstract

NKT cells are typically defined as CD1d-dependent T cells that carry an invariant TCR α-chain and produce high levels of cytokines. Traditionally, these cells were defined as NK1.1+ T cells, although only a few mouse strains express the NK1.1 molecule. A popular alternative marker for NKT cells has been DX5, an Ab that detects the CD49b integrin, expressed by most NK cells and a subset of T cells that resemble NKT cells. Interpretation of studies using DX5 as an NKT cell marker depends on how well DX5 defines NKT cells. Using a range of DX5 and other anti-CD49b Abs, we reveal major differences in reactivity depending on which Ab and which fluorochrome are used. The brightest, PE-conjugated r..