The present disclosure relates, inter alia, to compositions and methods, including chimeric proteins, and nucleic acids encoding the chimeric proteins having a first domain comprising an extracellular domain of a first transmembrane protein, a first secreted protein, or a first membrane-anchored extracellular protein and a second domain comprising an extracellular domain of a second transmembrane protein, a second secreted protein, or a second membrane-anchored extracellular protein, in which either or both of the first domain and the second domain decreases self-directed immune system activity when bound to its ligand/receptor. Accordingly, the present disclosure find use in the treatment of autoimmune diseases, and particularly, inflammatory bowel diseases.

Chimeric antigen receptors containing ROR1 antigen binding domains are disclosed. Nucleic acids, recombinant expression vectors, host cells, antigen binding fragments, and pharmaceutical compositions, relating to the chimeric antigen receptors are also disclosed. Methods of treating or preventing cancer in a subject, and methods of making chimeric antigen receptor T cells are also disclosed.