The Enigmatic Plasmacytoid T Cells Develop into Dendritic Cells with Interleukin (IL)-3 and CD40-Ligand

TLDR

A subset of CD4⁺CD11c⁻CD3⁻ blood cells can differentiate into dendritic cells when cultured with monocyte‑conditioned medium. The study demonstrates that tonsil‑derived CD4⁺CD11c⁻CD3⁻ cells are plasmacytoid T cells, an obscure cell type long observed in secondary lymphoid tissues. These cells undergo rapid apoptosis in culture unless rescued by IL‑3. They express CD45RA without lymphoid or myeloid markers, and upon CD40‑ligand addition they differentiate into dendritic cells that express low levels of CD13 and CD33.

Abstract

A subset of CD4+CD11c−CD3− blood cells was recently shown to develop into dendritic cells when cultured with monocyte conditioned medium. Here, we demonstrate that CD4+ CD11c−CD3− cells, isolated from tonsils, correspond to the so-called plasmacytoid T cells, an obscure cell type that has long been observed by pathologists within secondary lymphoid tissues. They express CD45RA, but not markers specific for known lymphoid- or myeloid-derived cell types. They undergo rapid apoptosis in culture, unless rescued by IL-3. Further addition of CD40-ligand results in their differentiation into dendritic cells that express low levels of myeloid antigens CD13 and CD33.