The impact of a multi-epitope melanoma helper peptide vaccine on Th1 cytokine production by responding lymphocytes.

e19028 Background: Melanomas produce soluble and cell-associated molecules that can suppress or alter antitumor immunity. Preclinical studies suggest the disease burden may alter the cytokine profile of helper T cell responses to cancer antigens. To describe the vaccine-induced production of Th2 or Th1 responses to helper peptides in the setting of advanced melanoma, we measured cytokine production of helper T cells responding to vaccination by 6 melanoma helper peptides (6MHP). We then analyzed results by measurable disease status. Methods: Thirty-nine patients with stage IIIB-IV melanoma received a 6MHP vaccine as a part of the UVA Mel41 clinical trial. For analysis of this correlative endpoint, antigen-reactive T cells were exposed to antigen, and supernatants (days 2 and 5) were assayed by cytokine bead arrays for Th1 and Th2 cytokines. Results: The dominant Th1 and Th2 cytokines detected were IFN-g and IL-5, respectively, though high levels of IL-2 were also produced early by sentinel lymph node lymp...