Recombinant DNA Advisory Committee - 10/7-8/91 
whereby the tense used in different portions of the form make it difficult to know where 
the patients are in the process of entering into the experiment. 
Dr. Wivel reiterated that the HGTS had asked Dr. Rosenberg to give a report after five 
patients, and to use the PCR assay for gene-modified cells in specimens taken from the 
regional lymph nodes or from other biopsies of subcutaneous tumor masses. 
Dr. Rosenberg responded that there have been no safety problems in his previously 
approved protocols. The protocol currently under review is an attempt to immunize 
patients against their own autologous tumors by using gene-modified tumor cells. It is 
based on previous animal experiments with adoptive transfer of lymphocytes as well as 
published experiments where gene-modified cells expressing cytokines have been shown 
to become more immunogenic. He showed experimental data where attempts were 
made to raise cytolytic cells against weakly immunogenic tumor cells. These experiments 
were minimally successful. If one transduces the gene for IL-2 into the tumor cells, 
however, highly tumor-specific cytolytic cells can be generated. It is the CD8 + cells that 
have shown effectiveness and are probably the cytolytic cells based on adoptive transfer 
in model systems. The major point is that one can stimulate cytolytic cells against a 
weakly immunogenic tumor by immunizing with gene-modified cells. 
Dr. Rosenberg stated that he plans to use the same retroviral vector that had been 
approved for use in the previous TNF TIL experiments. The vector contains the gene 
for TNF and the neomycin resistance gene. It has been shown that the TNF gene has 
been inserted into the tumor lines and that the tumor lines then produce message and 
secrete protein. When animals are injected with the gene-modified tumor cells, the 
tumor grows for eight to nine days and then spontaneously regresses. It is the TNF 
production by the tumor that leads to this regression. The assessment of the 
immunologic nature of this phenomenon is that it is mediated by T cells, presumably the 
cells that are specifically cytolytic. Animal experiments have indicated that when 
adoptively transferred, these T cells can mediate anti-tumor effects. 
Dr. Rosenberg said the protocol attempts to take advantage of that observation in two 
ways: (1) by immunizing patients with the gene-modified cells as a form of active 
immunization; and (2) by subsequently harvesting draining lymph node cells to be used 
for adoptive immunotherapy. He showed data from animal experiments illustrating that 
the genetic modification of the tumor cells causes them to spontaneously regress while 
immunizing the mouse against tumor rechallenge and stimulating the generation of 
tumor-specific killer cells. The treatment scheme is to resect the tumor as part of 
standard treatment. All of the patients who will be treated have advanced cancer that 
have failed all standard treatments. When tumor is resected from the patient, as part of 
the standard treatment or as part of a TIL protocol, these tumor cells will be established 
in culture for studies of the immunologic reaction of that patient against his/her own 
Recombinant DNA Research, Volume 15 
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