Figure 8

Anti-huHER2 antibodies elicited by HuRT-DNA. (a) Tumor-free survival in mice vaccinated with chimeric human/rat HER2 plasmid electroporated vaccine (HuRT)-DNA stratified according to anti-huHER2 levels above (high antibody (Ab) level) or equal to or below (low antibody level) the median after the first vaccination cycle (n = 5 mice per group). P < 0.05 between the two groups by Mantel-Haenszel test. (b) Isotypes of anti-HER2 antibodies. Sera were incubated with syngeneic or xenogeneic target cells (syn-HER2 and xeno-HER2, respectively), then indirect immunofluorescence was performed with fluorescein-labeled secondary antibodies to detect murine immunoglobulin (total Ig) or specific murine isotypes. (c) Anti-huHER2 antibodies elicited by HuRT-DNA caused a decreased huHER2 signaling in syn-HER2 cells. U = untreated cells; M = cells treated for the indicated times with sera from Mock-vaccinated mice; H = cells treated for the indicated times with sera from mice vaccinated with HuRT-DNA. Time of exposure to antisera is reported at the top of the figure. Densitometric analysis was performed. Band intensity was normalized over the corresponding actin, then the percentage decrease between M and H after the same incubation time was calculated and is shown under the corresponding H lane.