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Updated: Aug 19, 2025

Evaluation of T Follicular Helper Cells and Germinal Center Response During Influenza A Virus Infection in Mice
Published on: June 27, 2020
Antigen-presenting T cells provide critical B7 co-stimulation for thymic iNKT cell development via CD28-dependent
Masashi Watanabe1, Sofia Celli1, Farrah A Alkhaleel1
1Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Abstract:
Invariant natural killer T (iNKT) cell development in the thymus depends on T cell receptor recognition of CD1d ligand on CD4/CD8 double-positive thymocytes. We previously reported that B7-CD28 co-stimulation is required for thymic iNKT cell development, but the cellular and molecular mechanisms underlying this co-stimulatory requirement are not understood. Here we report that CD28 expression on CD1d-expressing antigen-presenting T cells is required for thymic iNKT cell development. Mechanistically, antigen-presenting T cells provide co-stimulation through an unconventional mechanism, acquiring B7 molecules via CD28-dependent trogocytosis from B7-expressing thymic epithelial cells, dendritic cells, and B cells and providing critical B7 co-stimulation to developing iNKT cells. Thus, the present study demonstrates a mechanism of B7 co-stimulation in thymic T cell development by antigen-presenting T cells.
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