Two weeks after the first vaccination mean tumor volume was 624 mm3 and 2167 mm3 in the group of mice vaccinated with rV neuT and V wt, respectively. Two out of si mice vaccinated with V wt were sacrificed at this stage. At the third week after vaccination 3 6 V wt vaccinated mice were sacrificed while 1 6 rV neuT vaccinated mice was tumor free. Only 1 6 mice of the group vaccinated with V wt was alive four weeks after the first vaccination. Conversely 6 6 rV neuT vaccinated mice were alive at this stage. At the 7th week, only 1 6 rV neuT vaccinated mice was alive and remained tumor free until the 30th week. The mean survival time of mice vaccinated with 106 pfu rV neuT versus those receiving the 106 pfu V wt dose was 9. 33 versus 2. 83 weeks.

Overall, when comparing the survival of BALB neuT mice upon vaccination it was observed that the risk of growth of SALTO tumor cells in the rV neuT vaccinated group was 0. 04 in comparison to V wt vaccinated group. In addition, the dose of the vaccine significantly affected mice survival. The risk of developing tumors in the 106 pfu and 107 pfu rV neuT vaccinated groups was 10. 26 and 14. 05 in comparison to the 108 pfu rV neuT vaccinated group. No difference was found between the 107 and 106 pfu rV neuT vaccination. These results suggest that rV neuT intratumoral vaccin ation is able to induce inhibition of the growth of trans planted salivary gland Neu positive tumor cells and that the effect of vaccination is dose dependent. The lower doses were able to induce in rV neuT vacci nated mice only a delay in SALTO tumor cells growth as compared to V wt vaccinated mice.

In this regard, the mean survival time of mice vaccinated with 108 pfu rV neuT versus those receiving the 107 pfu rV neuT and 106 pfu rV neuT doses was 27 versus 5. 25 weeks and 9. 33 weeks, respectively. Anti Neu humoral response following rV neuT vaccination Previous studies reported that anti Neu humoral response is required to inhibit mammary tumor growth in BALB neuT vaccinated mice. Antibody response to p185 Neu was quantitatively and qualitatively evaluated by im munoprecipitation following western blotting, Dacomitinib ELISA and immunofluorescence in order to determine whether differ ences in humoral response e isted between rV neuT or V wt administration before and after vaccination.

Specific anti Neu reactivity in sera from rV neuT vacci nated mice was visualized by immunoprecipitation followed by western blotting by using an anti Neu specific antibody, and LTR Neu and SALTO cells as antigen source. The e pression of p185 Neu in LTR Neu and in SALTO cells was analyzed by western blotting. As shown in Figure 3, Panel A, NIH3T3 fibroblasts did not e press p185 Neu, while LTR Neu and SALTO cells showed high levels of e pression of p185 Neu. Specific antibody response to Neu was qualitatively evaluated by indirect immuno fluorescence and immunoprecipitation analysis.