July 30, 1990, Human Gene Therapy Subcomnittee 
Dr. Parkman noted that the revised protocol still included reference to the use of an i.p. 
route of administration. However, he felt this was a minor administrative oversight in 
revising the protocol. 
Dr. Parkman noted the investigators had supplied a summary sheet of preclinical trials 
showing that the insertion of the human ADA gene into the peripheral blood leukocytes 
of cells from ADA-deficient patients appeared to normalize their function in vivo. He 
said this was important because one of the issues in the "Points to Consider" is the 
matter of an appropriate animal model. He said he had several questions about these 
trials: 
1. The data appear to consist primarily of information that was presented at 
the UCLA meeting last winter. What new data does Dr. Bordignon have 
on experiments that have been done since February, 1990? Has the NIH 
group done similar experiments since June 1? 
2. Are the experiments described a single experiment with one patient, or are 
they multiple experiments with multiple patients? If it is a single 
experiment with one patient, have the investigators been able to reproduce 
the findings in a second set of experiments? If it is with multiple patients, 
what was the person-to-person variation of the experiments? What was the 
patient's immune status? What was the patient's ADA level? Were the 
patient's cells capable of in vitro blastogenesis in response to stimulation 
with phytohemagglutinin or tetanus toxoid, either with or without 
exogenous interleukin-2 (IL-2)? Was the patient immunized to tetanus 
toxoid? 
3. Figure 2 is not interpretable. 
4. How many cells were given to each animal? How long after the animals 
were transplanted were the results in Figure 1 obtained? Were the 
untransfected cells treated in parallel with the transfected cells? If they 
were not treated in a parallel manner, were they transplanted immediately? 
What assays were done to show that equivalent viability and biological 
reactivity were present in the transfected and non-transfected cells? 
5. Were the allo-specific and tetanus toxoid-specific T cell clones obtained by 
primary limiting dilution analysis, or were they first expanded in bulk 
culture and then cloned by limiting dilution analysis? If there was an 
original bulk culture, what is the evidence that the alloreactive and tetanus- 
specific clones are derived from multiple precursors rather than a single 
antigen reactive cell? Has T cell receptor (TCR) rearrangement analysis 
been done on the clones to show that they are heterogenous, rather than 
Recombinant DNA Research, Volume 14 
