Lipocalin muteins specific to a predetermined antigen can be transduced into a T cell to bring therapeutic benefits to patients in need. In one example, a lipocalin mutein specific to a predetermined antigen (e.g., a target differentially expressed on the surface of a tumor cell) can be transduced into a T cell membrane to serve as an antigen receptor, offering benefits over conventionally deployed antibody-derived protein moieties such as a single chain variable fragment (scFv). Benefits include a more stable structure, leading to superior target engagement, for example. Further, lipocalin muteins specific to a predetermined antigen (e.g. an immunomodulatory target such as an immune checkpoint or costimulatory molecule) can be transduced into a T cell for secretion thereby, bringing an added therapeutic benefit. Specific examples of such modified T cells and methods of making and using the same are provided herein.
