Together with the high levels of HER2-reactive serum IgG levels (Figure 7N), our data suggest that VSVΔ51+T-DM1 treatment elicits a humoral response centered on CD4+ T-cell tumour infiltration and activation, systemic dendritic cell activation by VSVΔ51 or T-DM1, followed by anti-tumour IgG production. The gene discussed is CD4; the disease is neoplasm.