Immune synapse

In immunology, an immunological synapse (or immune synapse) is the interface between an antigen-presenting cell or target cell and a lymphocyte such as an effector T cell or Natural Killer cell. The interface was originally named after the neuronal synapse, with which it shares the main structural pattern. An immunological synapse consists of molecules involved in T cell activation, which compose typical patterns—activation clusters. Immunological synapses are the subject of much ongoing research.

The immune synapse is also known as the supramolecular activation cluster or SMAC. This structure is composed of concentric rings each containing segregated clusters of proteins—often referred to as the bull’s-eye model of the immunological synapse:

New investigations, however, have shown that a "bull’s eye" is not present in all immunological synapses. For example, different patterns appear in the synapse between a T-cell and a dendritic cell.

This complex as a whole is postulated to have several functions including but not limited to:

Recent research has proposed a striking paralelle between the immunological synapse and the primary cilium based mainly on similar actin rearrangement, orientation of the centrosome towards the structure and involvement of similar transport molecules (such as IFT20, Rab8, Rab11). This structural and functional homology is the topic of ongoing research

The initial interaction occurs between LFA-1 present in the p-SMAC of a T-cell, and non-specific adhesion molecules (such as ICAM-1 or ICAM-2) on a target cell. When bound to a target cell, the T-cell can extend pseudopodia and scan the surface of target cell to find a specific .

...
Wikipedia