Figure 2. Vaccinations with irradiated GM-CSF transduced melanoma cells. 
Mice were vaccinated with varying numbers of irradiated (5000 rad) GM-CSF 
transduced tumor cells. Animals were challenged with 5 x 10 5 live, wild type 
B16 tumor cells 7 days later. o animals dying of tumor challenge • animals 
protected against tumor challenge. 
Dilution experiments in which irradiated non-transduced cells were mixed 
with irradiated GM-CSF transduced cells indicated that not all of the cells 
needed to produce GM-CSF to induce a full systemic immune response. Indeed, 
full anti-tumor immunization potential was apparent over a reasonably wide 
range of GM-CSF concentrations. These dilution experiments indicated that an 
average production rate of approximately 36 nanograms/ 10 6 cells/24 hours was 
sufficient to induce the maximum protective immune response possible 
(Table 2 ) . 
Table 2 
Elect of a vc rate CM-CSF production rate. 
Avf. GM-CSF production 1 > mice tumor free SO day* a/ter 
360 ni/10 6 cells/74 hr 
I20n|/I0 6 cells/24 hr 
36 nj/10^ eellt/24 hr 
12 nf/10* eells/24 hr 
3.6 n|/10 6 cells/24 hr 
0 n»/10 6 cells/24 hr 
a Mice were vaccinated with varylnt number! of Irradiated GM-CSF transduced cells mixed 
with Irradiated nontransduced cells such that the totaj number of Immunlilnf cells was 
held constant at IxlO 7 and aveme GM-CSF production per cell were varied between 0 and 
360 n|/t0 6 cells/24 hr. 
b Mice were challenicd subcutaneously with 1x1 0^ live noniransduccd 8 1 6 cells 2 weeks 
sifter vaccination. 
chaJlence 0 
7/10 
7/10 
7/10 
3/10 
1/10 
0/10 
Recombinant DNA Research, Volume 17 
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