Identification of Melanoma-reactive CD4+ T-Cell Subsets From Human Melanoma Draining Lymph Nodes

Our laboratory has previously demonstrated that melanoma draining lymph node (MDLN) samples from stage III patients contained both CD4(+) and CD8(+) T cells that can be readily expanded to mediate tumor cell apoptosis in vitro and improve survival in mice bearing human melanoma xenografts. In this study, we investigated whether MDLN T cells contain melanoma-reactive CD4(+) T-cell compartment and what they are. To test this, we performed multiparametric (11-color and 6-color) fluorescence-activated cell sorting analyses to monitor phenotypic and functional property of CD4(+) T cells in response to melanoma cell antigen reexposure. Our results have demonstrated that the antigen reexposure could result in a generation of CD4(+)CCR7(+)CD62L(+)CD27(-) T-cell subsets with various effector cell-like properties. Within the CD4(+)CCR7(+)CD62L(+)CD27(-) T-cell compartment, in response to antigen reexposure, some of the cells expressed significantly upregulated CD40L and/or CXCR5, and some of them expressed significantly upregulated interleukin-2 and/or tumor necrosis factor-alpha. This may suggest the existence of melanoma- reactive CD4(+) "effector-precursor" cells within the expanded MDLN cells and their differentiation into various effector lineages in response to antigen restimulation. Recent clinical trials have demonstrated that effective adoptive cellular immunotherapy maybe enhanced by antigen-specific CD4(+) T cells. Therefore, results of this study may significantly benefit innovative design of + adoptive cellular immunotherapy that can potentially mediate enhanced and durable clinical responses.