CD4⁺ T-Cell Recognition of Mutated B-RAF in Melanoma Patients Harboring the V599E Mutation

The potential of antigen-directed cancer immunotherapy has not been fully realized, perhaps because many commonly targeted tumor associated proteins are not essential to maintaining the malignant cell phenotype. A constitutively activating mutation in the signaling molecule BRAF is expressed frequently in melanomas and may play an important role in the biology of this disease. A 29-mer B-Raf peptide incorporating the V599E mutation was used for in vitro stimulation of lymphocytes derived from melanoma patients, generating MHC class II-restricted CD4⁺ T cells specific for this peptide as well as for melanoma cells expressing B-Raf V599E. Mutated B-Raf exemplifies targets that may be ideal for immunotherapy.