To evaluate whether the upregulated CSF1R expression in Lal–/– CD11c+ cells is responsible for Lal–/– CD11c+ cell immunosuppressive and tumor stimulatory functions, isolated Lal+/+ or Lal–/– CD11c+ cells were pretreated with control IgG or anti-CSF1R antibody, and then cocultured with splenic CD4+ T cells in vitro or subcutaneously coinjected with B16 melanoma cells in vivo. This evidence concerns the gene CD4 and melanoma.