Developing T cells form an immunological synapse for passage through the β-selection checkpoint

The beta-selection checkpoint of T cell development tests whether the cell has recombined its genomic DNA to produce a functional T cell receptor beta (TCR beta). Passage through the beta-selection checkpoint requires the nascent TCR protein to mediate signaling through a pre-TCR complex. In this study, we show that developing T cells at the beta-selection checkpoint establish an immunological synapse in in vitro and in situ, resembling that of the mature T cell. The immunological synapse is dependent on two key signaling pathways known to be critical for the transition beyond the beta-selection checkpoint, Notch and CXCR4 signaling. In vitro and in situ analyses indicate that the immunological synapse promotes passage through the beta-selection checkpoint. Collectively, these data indicate that developing T cells regulate pre-TCR signaling through the formation of an immunological synapse. This signaling platform integrates cues from Notch, CXCR4, and MHC on the thymic stromal cell to allow transition beyond the beta-selection checkpoint.

Automated summary

Developing T cells establish an immunological synapse at the beta-selection checkpoint, which regulates pre-TCR signaling and promotes passage through this checkpoint. The immunological synapse integrates signals from Notch, CXCR4, and MHC to facilitate transition beyond the beta-selection checkpoint.