The present invention relates to the field of cell immunotherapy and more particularly to a new generation of chimeric antigen receptors (CAR), allowing the control of immune cells endowed with such CARs through the interaction with small molecules. More particularly, the present invention relates to chimeric antigen receptor which comprise in at least one ectodomain a molecular switch turning the antigen binding function of the receptor from an off to on state, and vice versa. The present invention thus provides more controlled and potentially safer engineered CAR endowed immune cells, such as T- lymphocytes.
