Human mast cells costimulate T cells through a CD28‐independent interaction |
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| Authors: | Jolien Suurmond Annemarie L. Dorjée Tom W. J. Huizinga René E. M. Toes |
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| Affiliation: | Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands |
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| Abstract: | Mast cells are innate immune cells usually residing in peripheral tissues, where they are likely to activate T‐cell responses. Similar to other myeloid immune cells, mast cells can function as antigen‐presenting cells. However, little is known about the capacity of human mast cells to costimulate CD4+ T cells. Here, we studied the T‐cell stimulatory potential of human mast cells. Peripheral blood derived mast cells were generated and cocultured with isolated CD4+ T cells. In the presence of T‐cell receptor triggering using anti‐CD3, mast cells promoted strong proliferation of T cells, which was two‐ to fivefold stronger than the “T‐cell promoting capacity” of monocytes. The interplay between mast cells and T cells was dependent on cell–cell contact, suggesting that costimulatory molecules on the mast cell surface are responsible for the effect. However, in contrast to monocytes, the T‐cell costimulation by mast cells was independent of the classical costimulatory molecule CD28, or that of OX40L, ICOSL, or LIGHT. Our data show that mast cells can costimulate human CD4+ T cells to induce strong T‐cell proliferation, but that therapies aiming at disrupting the interaction of CD28 and B7 molecules do not inhibit mast cell mediated T‐cell activation. |
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| Keywords: | CD4 positive T lymphocytes Costimulation CD28 antigens Mast cells T‐cell proliferation |
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