CD4 and melanoma: To determine the frequency of circulating anti-TAA Th cells in HLA-DR*0401+ melanoma patients, CD4+ T cells were freshly isolated from patient peripheral blood (Table 1) and incubated with PE-labeled HLA-DR4 tetramer complexes containing the MAGE-6121–144, MAGE-6246–263, EphA253–62, EphA263–75, EphA2663–678 TAA epitopes, or the (positive control) influenza A matrix (FluM1)60–73 viral epitope, then analyzed by flow cytometry (Figure 1).