1. An immunoreactive cell comprising: a. an antigen recognizing receptor that binds the first antigen with low affinity, where binding of the receptor to the first antigen activates an immunoreactive cell, and b. a chimeric costimulatory receptor (CCR) that binds to a second antigen and stimulates an immunoreactive cell. 2. An immunoreactive cell according to claim 1, wherein the cell is selected from the group consisting of a T cell, a natural killer (NK) cell, a cytotoxic T lymphocyte (CTL), a regulatory T cell, a human embryonic stem cell, and a pluripotent stem cell, of which lymphoid cells can be differentiated. 3. An immunoreactive cell according to claim 1 or 2, wherein the antigen is a tumor or pathogen antigen. An immunoreactive cell according to claim 1 or 2, wherein said antigen recognizing receptor is a T cell receptor (TCR) or a chimeric antigen receptor (CAR). An immunoreactive cell according to claim 1 or 2, wherein said antigen recognizing receptor is exogenous or endogenous. An immunoreactive cell according to claim 1 or 2, wherein said antigen recognizing receptor is expressed recombinantly. An immunoreactive cell according to claim 1 or 2, wherein the antigen recognizing receptor is expressed from a vector. An immunoreactive cell according to claim 1 or 2, wherein the chimeric costimulatory receptor (CCR) is expressed from a vector. An immunoreactive cell according to claim 1 or 2, wherein said immunoreactive cell is autologous. An immunoreactive cell according to claim 1 or 2, wherein said first and second antigens are selected from the group consisting of CAIX, CEA, CD5, CD7, CD10, CD19, CD20, CD22, CD30, CD33, CD34, CD38, CD41, CD44, CD49f , CD56, CD74, CD133, CD138, cytomegalovirus (CMV) infected cell antigen, EGP-2, EGP-40, EpCAM, erb-B2, 3, 4, FBP, fetal acetylcholine receptor, folate receptor-a, GD2, GD3, HER-2, hTERT, IL-13R-a2, x-light1. Иммунореактивная клетка, содержащая:a. узнающий антиген рецептор, который связывает первый антиген с н
