GENERATION OF TUMOR-SPECIFIC CTLS FROM MELANOMA PATIENTS BY USING PERIPHERAL-BLOOD STIMULATED WITH ALLOGENEIC MELANOMA TUMOR-CELL LINES - FINE SPECIFICITY AND MART-1 MELANOMA ANTIGEN RECOGNITION

PBLs were isolated from 13 patients with metastatic melanoma. Mixed ly mphocyte tumor cell cultures (ML TCs) were established (15 times) by u sing irradiated HLA-matched (one class I locus) allogeneic melanoma tu mor cell lines (13 times) or autologous melanoma tumor cell lines (two times) in medium containing 120 IU/ml IL-2 and 100 IU/ml IL-4. PBLs g rew to levels that could be assessed for functional reactivity 9 of 15 times. In seven of nine cases, CD3(+)CD8(+) CTLs grew from MLTCs that were tumor specific; five were restricted by HLA-A2 and two were rest ricted by HLA-A24. Four of the tumor-specific CTL lines lysed autologo us fresh tumor cells. Tumor-specific CTLs from two of three patients h ad cytolytic activity identical with tumor-infiltrating lymphocytes (T IL) derived from tumor biopsies removed earlier and grown in high conc entrations (6000 IU/ml) of IL-2. Three of the HLA-A2-restricted tumor- specific CTLs were shown to recognize 293 cells transfected with HLA-A 2.1 cDNA and the gene encoding the melanoma Ag, MART-1. In addition, t hese CTLs recognized the T2 cell line pulsed exogenously with the pept ide MART-1(27-35), which is the nine-amino acid immunodominant epitope of the MART-1 Ag recognized on melanoma tumor cells by nearly all HLA -A2-restricted TIL. Thus, we have demonstrated the ability to generate tumor-specific CTLs from PBLs that are similar in their reactivity to TIL. This technique obviates the need for autologous tumor tissue and suggests that PBLs contain sufficient CTL precursors for use in gener ating antitumor CTLs for cellular immunotherapy trials.