According to the view of most researchers, a special subset of lymphocytes, called T helper cells, specifically Th1 and Th17, play a key role in the development of the lesion. Under normal circumstances, these lymphocytes can distinguish between self and non-self. However, in a person with MS, these cells recognize healthy parts of the central nervous system as foreign and attack them as if they were an invading virus, triggering inflammatory processes and stimulating other immune cells and soluble factors like cytokines and antibodies. Many of the myelin-recognizing T cells belong to a terminally differentiated subset called co-stimulation-independent effector-memory T cells. Recently other type of immune cells, B Cells, have been also implicated in the pathogenesis of MS and in the degeneration of the axons.