PATHOLOGY

Detailed explanation-1: -1. During immune-mediated clearance of virally infected cells from the brain, CD8+ cytotoxic T lymphocytes (CTLs) form immunological synapses with virally infected cells (8). In these CTLs, IFN- is polarized toward the antigenic target cell (9).

Detailed explanation-2: -However, cells of the immune system also form synapses that, although more transient than neural synapses, are nevertheless structured and essential for cell activation. T cells, B cells and natural killer cells form synapses that are referred to as immunological synapses (ISs).

Detailed explanation-3: -Immunological Synapse (IS) is a multi-molecular assembly functional structure formed at the interface of T lymphocyte and antigen presenting cell. These molecules include antigen presenting molecules, adhesion molecules, co-stimulatory molecules, and inhibitors or checkpoint molecules, etc.

Detailed explanation-4: -The immunological synapse (IS) is a stable cell–cell junction between a thymus-derived lymphocyte (T cell) and an antigen-presenting cell (APC). The IS concept provides a number of insights into the T cell activation process. Firstly, it provides a stop signal that coordinates antigen recognition and T cell migration.

Detailed explanation-5: -CTLs are activated by type I NKT cells via cytokines (IL-2, IL-12, IFN-, and TNF-) and costimulatory molecules (CD40L and CD28). In contrast, increased expression of Th2 cytokines (IL-4) and other costimulatory molecules (CTLA-4 and PD-L) inhibits CTL production or activation.