ERBB2 and breast cancer: They also showed functional capacity that included the ability to sensitize in vivo against both MHC class I (rHER-2 p66) and MHC class II (OVA) antigens, as well as therapeutic activity in a murine model of HER-2pos breast cancer, when pulsed with novel Th epitopes from the rErbB2/HER2 ECD.