with infusions of autologous polyclonal T cells activated for short term (<2 
weeks) growth in culture. Since enhanced immune function has been 
observed in children with inherently defective T cells, there is good reason to 
expect that infusion of normal T cells obtained from HIV seronegative twins 
should be at least as effective in reconstituting immune function in the HIV 
infected twin. 
3.2 In Vivo Human Experiments with TIL Transduced with the LNL6 Vector 
The human gene transfer N2/TIL clinical protocol (86-C-183c) was approved 
in 1989. In this study, 10 patients with advanced malignant melanoma 
received tumor infiltrating lymphocytes (TIL) that have been marked with the 
safety-modified N2 vector called LNL6. Extensive safety studies on the 
retroviral supernatant prior to transduction of human TIL, the transduced TIL 
before infusion into the patient, and the patients who received the gene 
marked TIL were performed. 
In summary of the safety data, there have been no side effects or toxic 
reactions due to the gene transfer. In addition, there has been no evidence of 
replication-competent virus in any retroviral supernatant used for clinical 
studies, no consistent differences in the pattern of cell growth, phenotype, or 
cytotoxic function in any preparation of gene-transduced TIL, and no 
lymphocyte population has developed IL2 independence. There has also 
been no evidence of viral exposure for any of the 1 0 patients based on 
Western analysis as well as 3T3 amplification with the S+L- of patient serum. 
In short, the data acquired to date demonstrate no abnormalities, side effects, 
toxicities, or pathology due to the retroviral-mediated gene transfer 
procedure. 
3.3 Assessment of the Safety of Retroviral-mediated Gene Transfer in 
Rhesus Monkeys and Humans 
In the ADA-deficient SCID protocol, a total of approximately 20 infusions of up 
to 2 x 10io cultured cells has been performed, and no significant side effects 
related to the cell infusions have been observed. In addition, there have 
been no side effects related to gene transfer. Similarly, in the N2/TIL protocol, 
there have been no side effects due to gene transfer and no evidence of 
infection by replication competent virus. Since foreign DNA is inserted 
randomly into the genome of cells that are reinfused into the patient, however, 
there is some potential for the insertional event to result in an unfavorable 
outcome. If the insertion disrupts a gene essential for maintaining cell 
function, that particular cell might die. More threatening is the possibility that 
insertion may initiate oncogenic transformation of the cell. The magnitude of 
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