
																
																	CD28 costimulatory signals in T lymphocyte activation: Emerging functions beyond a qualitative and quantitative support to TCR signalling
																
																
																
															Keywords: MHC, major histocompatibility complex; TCR, T-cell receptor; APC, antigen presenting cell; Ig, immunoglobulin; IL, interleukin; IS, immunological synapse; PLCγ1, phospholipase Cγ1; LAT, linker for activation of T cells; Grb2, growth-factor receptor-bound