Abstract: The present invention provides an immune effector cell that comprises a chimeric antigen receptor (CAR) specific for a tag of a tagged polypeptide, wherein said polypeptide binds to an antigen of a target cell, and a chimeric costimulatory receptor (CCR) specific for a further antigen. The CCR is not able to mediate said immune response on its own but boosts the immune response of said immune effector cell triggered by the CAR.

Abstract: The present invention provides an immune effector cell that comprises a chimeric antigen receptor (CAR) specific for a tag of a tagged polypeptide, wherein said polypeptide binds to an antigen of a target cell, and a chimeric costimulatory receptor (CCR) specific for a further antigen. The CCR is not able to mediate said immune response on its own but boosts the immune response of said immune effector cell triggered by the CAR.

Abstract: The present invention provides a composition comprising A) immune cells such as T cells comprising a) an inducible gene expression system comprising I) a first nucleic acid comprising a drug-inducible promoter operably linked to a second nucleic acid, and II) said second nucleic acid encoding a polypeptide or a non-coding RNA (ncRNA) which decreases cell surface expression level of major histocompatibility complex (MHC) class I relative to cell surface expression level of MHC class I of an immune cell that does not express said polypeptide or ncRNA; and b) a third nucleic acid encoding a chimeric antigen receptor (CAR) or T cell receptor (TCR); and B) a drug that induces said drug-inducible promoter. Preferentially, said polypeptide may be a viral protein which decreases cell surface expression level of major histocompatibility complex (MHC) class I relative to cell surface expression level of MHC class I of an immune cell that does not express the viral protein.

Abstract: The current disclosure provides for immune cells expressing immune receptors comprising i) a polypeptide having an antigen binding domain, a TCR ?-chain constant domain, and a TCR ?-chain transmembrane domain; and/or ii) a polypeptide having an antigen binding domain, a TCR ?-chain constant domain, and a TCR ?-chain transmembrane domain. The current disclosure also provides for immune cell expressing immune receptors comprising an antigen binding domain, and a transmembrane domain, wherein the antigen binding domain specifically binds a binding moiety that in turn specifically binds a target, for example, a cancer cell. The immune cells, optionally in combination with the binding moiety, can be used in medical treatment, preferably the treatment of a cancer.

Abstract: The present invention provides a regulatory T (Treg) cell expressing an antigen chimeric receptor (CAR) comprising a) at least one antigen binding domain, b) a transmembrane domain, and c) a cytoplasmic signaling domain comprising at least one primary cytoplasmic signaling domain and at least the co-stimulatory signaling domain of CD137, wherein said antigen binding domain specifically binds an antigen that is expressed on the surface of a target cell or a tag of a tagged polypeptide that binds to an antigen expressed on the surface of a target cell or a soluble antigen. Compositions comprising said Treg cells, and methods of enrichment and analysis of activated Tregs that express said CAR are also disclosed.

Abstract: The present invention provides an immune effector cell that comprises a chimeric antigen receptor (CAR) specific for a tag of a tagged polypeptide, wherein said polypeptide binds to an antigen of a target cell, and a chimeric costimulatory receptor (CCR) specific for a further antigen. The CCR is not able to mediate said immune response on its own but boosts the immune response of said immune effector cell triggered by the CAR.