Origin and main features of the various sublines of melanoma LG2-MEL. Sublines LG2-MEL-205, -206, -207, -220 were obtained by cloning of LG2-MEL, a melanoma cell line that was established from a lymph node metastasis of patient LG2. Clonal subline LG2-MEL-5-35 was derived from subline LG2-MEL-205 after two mutagenic treatments, as previously described (10). Subline LG2-MEL-5-35isc3.1.1 is resistant to the anti-LG2-B CTL clones and was obtained by in vitro immunoselection of LG2-MEL-5-35 with the anti-LG2-B CTL clones. This subline has lost expression of HLA-A32, -B44 and -Cw4. Subline LG2-MEL-220 was obtained by cloning of LG2-MEL and has lost the HLA-A24, -B35 and -Cw4 alleles. The lysis of the melanoma sublines by the different CTL was measured in a standard chromium-release assay and is shown on the right.