Compositions, methods, and computer systems related to making and administering modified T cells

A method of immunotherapy of a subject, comprising:

• administering to a subject afflicted by or having symptoms of cancer, a therapeutically effective amount of one or more T cells bearing one or more multi-specific Chimeric Antigen Receptors including at least two antigen binding sites, wherein the multi-specific Chimeric Antigen Receptors have decreased antigen binding affinity for a target antigen expressed on normal cells compared to the antigen binding affinity for the same target antigen expressed on cancer cells, wherein the target antigen is expressed at a relatively higher cell surface density on cancer cells as compared to normal cells.

A method for immunotherapy of a subject comprising:

• administering to a subject afflicted by or having symptoms of viral infection, a therapeutically effective amount of one or more T cells bearing one or more multi-specific Chimeric Antigen Receptors including at least two antigen binding sites, wherein the multi-specific Chimeric Antigen Receptors have decreased avidity for binding to normal cells compared to the avidity for binding to virally infected cells, and wherein the affinity of at least one antigen binding site of the multi-specific Chimeric Antigen Receptor has a lower affinity for a viral target antigen that is expressed at a relatively higher cell surface density on virally infected cells as compared to normal cells.