To test the potency of isotype-switched tumor-specific antibody in the metastasis model without the confounding influence of tumor-specific CD4+ T cells, SWHELRag2−/− mice were challenged i.v. with tumor cells, followed by 2 i.p. injections of an agonistic anti-CD40 monoclonal antibody to provide helper signals to the B cells. The gene discussed is CD4; the disease is neoplasm.