ERBB2 and neoplasm: In mice having a HER2-positive, tumor rat HER2/neu protein derivativeP5, which is a CTL-specific peptide, can efficiently stimulate CTLresponses,47−50 Monophosphoryl lipid A (MPL), an agonist of toll-like receptor 4(TLR4), is one of the hydrophobic immune-stimulating compounds.51,52 Pan HLA-DR epitope peptide (PADRE) is one of the most effectivecompounds to trigger CD4+ responses in both humans and mice.