Histopathologic analysis of the vaccination site. (A) WT, (B) GM-CSF^−/−, (C) IL-5^−/−, and (D) βc^−/− mice were immunized subcutaneously on the abdomen with 10⁶ irradiated B16-GM cells. As control, WT mice were immunized with 10⁶ irradiated B16 cells (E). Five days later, tissue samples were collected and fixed in formalin before paraffin embedding. Samples were then stained with hematoxylin and eosin. Magnification: 10 × 2.5 and 10 × 20.