Galpin/DA/N2 IIIBenv 
and expressed the modified HIV-1 env protein. Subsequent studies have shown that 
BCenvAV3 target cells did not express V3 loop region, but were still subject to lysis 
by HIV-1 env/rev-specific CTL. 59 
BALB/c mice were injected with crude HIV-IT (V) as above, and 
splenocytes stimulated multiple times in vitro with irradiated BCenv and 
subsequently with BCenvAV3. The effector cells were tested on BCenv, 
BCenvAV3, and BC control target cells. The HIV-IT (V)-induced CTL exhibited 
substantial lysis of BCenv and BCenvAV3 target cells compared to BC control cells 
(Figure 12). Furthermore, these CTL were previously shown to recognize the 
P18IIIB and P18MN peptides. Therefore, this CTL population contains effector 
cells that recognize not only determinants contained within the V3 hypervariable 
region, but also HIV-1 env epitopes outside the V3 hypervariable region that are 
potentially more conserved epitopes. The CTL epitopes recognized outside the V3 
hypervariable region could be determinants located in the gpl20 or gp41 portions of 
the env protein or determinants residing in the rev protein. Envelope-specific lysis 
by HIV-IT (V) induced CTL was confirmed by testing BC cells infected with a 
vaccinia-gpl60 recombinant virus, which expressed the HIV-1 env, but not the rev 
or neo r genes. 
3.1. 1.6 Ability of Induced CTL to Lyse Cells Infected with Divergent HIV-1 
Strains 
An effective anti-HIV- 1 treatment must be designed to generate responses 
that are capable of recognizing the multiple virus isolates or strains of HIV-1 
present in patients. Extensive serological analysis of neutralizing antibodies and 
DNA sequence analysis of the V3 hypervariable region (principal neutralizing 
determinant) of the HIV-1 envelope proteins of different HIV-1 isolates has 
indicated that most HIV-1 specific neutralizing antibodies are virus strain-specific, 
-’ 9 Chada, et al., J. Virol, In Press. 
Recombinant DNA Research, Volume 17 
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