IL-2. The dose of radiation to treat the fibroblasts (3,000 rads) was chosen following consultation 
with Drs. George Jones and Klaus Erikson of the UCSD Department of Radiobiology. This dose will 
result in the survival of less than one in 10® cells (data extrapolated from a published study on the 
radiation sensitivity of normal fibroblasts-Comforth MN and Bedford JS Radiation Research 
111:385,1987). Furthermore, in our animal studies with murine fibroblasts, this dose of radiation did 
not affect the efficacy of immunization with a mixture of tumor cells and irradiated, transduced 
fibroblasts. 
5.2 Potential Toxicity 
Local toxicity at the sites of immunization are not expected to occur. If severe inflammation occurs at 
the site of injection, this will be treated by either topical steroid therapy and/or surgical excision of 
the inflamed tissues as indicated. 
Hypersensitivity reactions are unlikely to occur, since the injected material is comprised of minimally 
modified cells. Systemic toxicity related to IL-2 administration should not occur as the low levels of 
IL-2 secreted by the genetically modified cells should not significantly effect systemic IL-2 
concentrations. 
There are several theoretical toxicities related to the use of retroviral mediated gene transfer. These 
theoretical toxicities are not expected to occur as the retrovirus utilized for gene transfer has been 
modified to prevent these toxicities. The retroviral vector has been altered to prevent viral replication 
by the deletion of viral gag, pol and env genes. Hence, the IL-2 retroviral vector is replication 
defective and patients' cells are never exposed to a replication competent virus. Replication 
competent retrovirus may theoretically develop by recombination between the IL-2 vector and viral 
gene sequences in the packaging cell line utilized to produce the retroviral vector. This type of 
recombination has rarely been observed after extended culture. Hence, all retroviral vector 
supernatants used to infect patient cells will be screened for replication competent virus by standard 
assays (15). It is theoretically possible for the retroviral vector to insert the transgene into a proto- 
oncogene or tumor suppressor gene resulting in cellular transformation by insertional mutagenesis. 
The likelihood of this occurring is extremely small. 
The neo 11 gene transferred into the genetically modified tumor cells inactivates neomycin and related 
antibiotics such as amikacin. As the genetically modified cells will be injected subcutaneously, local 
expression of the neo R gene is unlikely to effect treatment with these antibiotics at other sites. In 
addition, other more commonly used antibiotics such as gentamycin and tobramycin are not 
inactivated by the neo R gene. Hence, the introduction of this gene into a local area of the patient is 
not expected to affect clinical management of infections. 
5.3 Treatment of Toxicity 
Local toxicity at the sites of cell administration will be treated with either topical steroids and/or 
surgical excision of the injection site as deemed appropriate. Hypersensitivity reactions may occur. 
Chills, fever and/or rash may be treated symptomatically with antipyretics and antihistamines. 
Patients should not be treated prophylactically. 
Should arthralgias, lymphadenopathy or renal dysfunction occur, the investigators should be notified 
and treatment with corticosteroids and/or antihistamines may be instituted. Anaphylactoid type 
hypersensitivity reactions are not anticipated. However, should anaphylaxis occur, administration of 
epinephrine, fluids, steroids and cardiopulmonary support should be instituted as needed. 
Recombinant DNA Research, Volume 18 
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