Fig. 1.

Tumor protection induced by HER-2 plasmid vaccination in the HHD syngeneic tumor transplantation model. a Surface HER-2 expression by the transplantable tumor cell lines MC-2 and MC-2/HER-2 was measured by flow cytometry using the HER-2 specific antibody or relevant isotype control. b HHD mice (n = 5/group) were given a s.c. tumor challenge with 70.000 MC-2 or MC-2/HER-2 cells, and animals were monitored for the development of palpable tumors. c HHD mice were immunized two times at 2-week intervals by i.d. injection and electroporation with HER-2 plasmid (n = 12 mice/group) or pVAX control vector (n = 12 mice/group). Fourteen days after the final immunization, mice were challenged with 70.000 MC-2/HER-2 cells s.c. in the right flank. d HHD mice (n = 12/group) vaccinated with HER-2 plasmid or pVAX control were challenged with MC-2 or MC-2/HER-2 tumor cells. The data shown are combined from two separate experiments