cell surface of melanoma cells. Injection of the IL-2 secreting tumor cells into 
nude mice led to tumor rejection while unmodified parental cells were not 
rejected. Irradiation of the genetically altered melanoma does not immediately 
abrogate IL-2 secretion (see appendix F). IL-2 was continuously secreted for 2-3 
weeks after lethal irradiation in amounts comparable to non-irradiated transduced 
cells. 
2.7 Rationale 
We propose to study whether immunization with allogeneic melanoma 
cells expressing a recombinant human IL-2 gene can be well tolerated 
without evident toxicity. There is substantial experience at MSKCC and at 
other institutions that has established the general safety of immunization 
using irradiated allogeneic tumor cells. The choice of allogeneic HLA-A2- 
positive tumor cells is based on two considerations. First, the use of a 
single established immunizing cell line bypasses the necessity to infect 
autologous tumor cells for each patient. Growing autologous tumor cells 
in tissue culture can be a difficult and time-consuming procedure. Since 
approximately 40% of North Americans are HLA-A2 positive, a tumor 
vaccine produced from HLA-A2 matched melanoma cell lines could be 
used in a substantial subpopulation of melanoma patients. Preclinical 
studies have been performed with a single cell line, SK-MEL-29. This 
cell line expresses a number of restricted melanocyte differentiation 
antigens, as determined by typing with monoclonal antibodies, and class II 
MHC antigens. In addition, SK-MEL-29 was derived from a patient (AV) 
with extensive stage III melanoma who was shown to have cytotoxic 
CD8-positive T cells in his peripheral blood that lysed autologous tumor 
in an HLA-A2 restricted fashion (22,23) (see Sections 2.2 and 2.8). 
Despite extensive and recurrent melanoma, patient AV is alive and free of 
disease more than 15 years after his initial treatment. Second, there is 
substantial evidence that melanoma cells can present restricted shared 
antigens (i.e. antigens expressed by autologous and allogeneic melanoma 
tumors but not certain non-melanoma cell types) to autologous T cells. 
The protocol will be restricted to patients who are HLA-A2 positive. 
Third, there is evidence that IL-2 secretion by tumor cells increases the 
frequency of tumor specific cytotoxic precursors and CTL’s (58). 
2.8 Melanoma Cell Line 
A well characterized and established melanoma cell line, SK-MEL-29, has 
been used for expression of IL-2. SK-MEL-29 is a well characterized 
melanoma cell line that is known to express a number of melanocyte 
differentiation and gangliosides antigens (51, 55). SK-MEL-29 was 
Recombinant DNA Research, Volume 15 
