Spontaneous immune response to NY-ESO-1 antigen in SS case 2. (A) The presence of NY-ESO-1-specific circulating antibodies was assessed by ELISA using serial serum dilutions. (B) NY-ESO-1-specific CTLs were assessed among circulating CD8+ T lymphocytes, 1 wk after in vitro stimulation with peptide NY-ESO-1_157-165, using fluorescent soluble HLA-A2/NY-ESO-1 peptide multimers and anti-CD8 mAb.