Naive T cells require a co-stimulatory signal delivered by induced expression of B7 molecules on the surface of an antigen-presenting cell that is recognized by a co-stimulatory receptor CD28 on the surface of T cells, thereby leading to proliferation of T cells.
B7 molecules are the cell surface protein ligands. They acts as ligands for the CD 28 receptor family. The signals produced by them are costimulatory or coinhibitory.
Proliferation is the process of multiplying rapidly of the T cells in immune system. This occurs to create several memory cells for any foreign pathogen or the proliferation occurs in order to fight an infection in the body.
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