The invention is directed to a modified T cell receptor (TCR) comprising an amino acid sequence of a wild-type (WT) TCR with no more than three amino acid substitutions, wherein the modified TCR, as compared to the WT TCR, (i) has an enhanced ability to recognize target cells when expressed by CD4+ T cells and (ii) does not exhibit a decrease in antigen specificity when expressed by CD8+ T cells. Polypeptides, proteins, nucleic acids, recombinant expression vectors, host cells, populations of cells, antibodies, and pharmaceutical compositions related to the modified TCR also are part of the invention. Further, the invention is directed to methods of detecting a diseased cell in a host, methods of treating or preventing a disease in a host, and methods of identifying a candidate adoptive immunotherapy TCR.