Immunological Synapse Formation Between Helper T Cells and Antigen-Presenting Cells

Immune cells communicate with each other via the interaction of multiple receptors, forming a specialized junction—an immunological synapse. This synapse serves as a site for exchanging signaling molecules essential for an immune response.

To study immunological synapse formation in vitro, begin with a basement matrix-coated microwell slide containing an adherent culture of activated human antigen-presenting cells, APCs.

The activated APCs present antigens bound to major histocompatibility complex or MHC-II molecules on their surface, essential for T cell activation. These cells are labeled with a blue fluorescent dye for easy identification.

Treat the wells with recombinant human helper T lymphocytes. These helper T lymphocytes express green fluorescent protein-tagged membrane proteins — CD63 found in secretory vesicles. This enables the tracking of secretory vesicles.

Lymphocytes' T cell receptors interact with MHC-antigen complexes on the APCs, bringing the helper T lymphocytes near the antigen-presenting cells, resulting in conjugation.

Upon conjugation, co-stimulatory signaling molecules on the APCs interact with lymphocyte receptors—forming a cluster around the conjugation si