The relative importance of CTL and antibodies in rejecting Her-2/neu-expressing tumors was evaluated in preventive and therapeutic models by DNA vaccination. Four human Her-2/neu-expressing plasmids (pNeuTM, pNeuECD, pNeuTM-gDs, and pNeuECD-gDs) were generated encoding either the transmembrane and extracellular domains or the extracellular domain. Interestingly, these plasmids demonstrated substantial difference in inducing Her-2/neu-specific serum IgG according to their signal sequence when injected in BALB/c mice. pNeuTM and pNeuECD induced high serum IgG titers. pNeuTM-gDs and pNeuECD-gDs induced low or very low serum IgG titers, respectively. As a result, mice vaccinated with not only pNeuECD but also pNeuECD-gDs exhibited complete eradication of a small number of tumor cells. Nevertheless, when the number of tumor cells was increased in a therapeutic model, only pNeuECD exhibited statistically significant antitumor immunity. These studies demonstrate that strong CTL may be sufficient in tumor prevention, but the collaboration of CTL and antibody may be required in tumor therapy.
- DNA vaccine
- Tumor immunotherapy
ASJC Scopus subject areas
- Infectious Diseases
- Public Health, Environmental and Occupational Health