Galpin/DA/N2 IIIBenv 
geneticin (G4IX) for neo r , and monitored for HIV-1 env expression. In this manner, a 
unique autologous HIV-1 IIIBenv-expressing CTL target cell population was established 
for each monkey. 
3.2.1 CTL Induction 
One Rhesus monkey was injected IM with a total of 3 x 10 7 cfu of purified, 
formulated HIV-IT (V). Injections were distributed at six sites comprising the upper 
left and right biceps (0.5 ml/site), and the two sites each for left and right quadriceps 
(0.5 ml/site). Three complete injections (6 sites/injection) were given at two-week 
intervals. Blood samples were obtained immediately prior to each injection, and 
isolated PBMC were restimulated with irradiated autologous HIV-1 env-expressing 
target cells and after 7 days analyzed for HIV-1 env-specific CTL activity (standard 4 
hour -^Cr-release assay). Cytotoxic T-cell activity was demonstrated in the monkey 
following the first HIV-IT (V) injection (Figure 16) and activity was maintained 
following a second injection. Therefore, these results indicated that marked CTL 
activity was induced in a normal Rhesus monkey injected with HIV-IT (V). CTL 
induction has been demonstrated in six additional Rhesus monkeys, using 6 different 
vector preparations. Additional studies were carried out in two baboons injected with 
different vector preparations. Restimulated PBMC from one baboon injected twice IM 
with a total dose of 3 x 10 7 cfu of purified, formulated HIV-IT (V) show 
HIV-1 env-specific CTL activity. Restimulated PBMC from a baboon injected with 3 
x 10 6 cfu did not show CTL activity suggesting that the threshold for CTL induction 
may be between 3 x 10 6 to 3 x 10 7 cfu. 
3.2.2 Antibody Induction 
Antibody responses specific for the HIV-1 env protein were evaluated in a 
baboon following one and two IM injections with 1 x 10 7 cfu purified, formulated 
HIV-IT (V). Serum samples were obtained following each injection and evaluated for 
binding to purified HIV-1 gpl20 protein-coated microtiter wells by ELISA. Serum 
Recombinant DNA Research, Volume 17 
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