Purpose: We initially observed that the presence of circulating NY-ESO-1- and/or Melan-A-specific T cells in patients with stage IV melanoma was significantly associated with prolonged survival. Here, we report the ways in which the phenotypes and functions of these T cells differentially affect survival in patients preselected for NY-ESO-1 and/or Melan-A reactivity.
Experimental design: We assayed functional antigen-reactive T cells recognizing NY-ESO-1 and/or Melan-A after in vitro stimulation using overlapping peptide pools. After restimulation, we assayed six cytokines simultaneously by intracellular cytokine staining. This allowed us to analyze the functional antigen response of both CD4(+) and CD8(+) T cells at the single-cell level.
Results: We observed that NY-ESO-1 stimulated mainly CD4(+) T cells, whereas Melan-A more often stimulated CD8(+) T cells. NY-ESO-1 reactivity was not associated with an additional impact on survival, whether CD4(+) T cells, CD8(+) T cells, or both types of T cells were responding. In contrast, recognition of Melan-A by CD4(+) T cells was associated with reduced survival in our cohort of patients preselected for NY-ESO-1 and/or Melan-A reactivity (that is, in patients with exceptionally long survival). We further observed a negative effect on survival in patients with CD4(+) T cells producing IL4 and IL17 upon Melan-A stimulation. Their prognosis was comparable to patients without any Melan-A reactivity.
Conclusions: The nature and prognostic impact of specific T-cell responses is different according to targeted antigen. Independent from phenotype and functional aspects, NY-ESO-1 reactivity is associated with good prognosis. In terms of Melan-A, antigen-specific CD8(+) but not CD4(+) responses are associated with prolonged survival. Clin Cancer Res; 20(16); 4390-9. ©2014 AACR.
©2014 American Association for Cancer Research.