RAG2 and neoplasm: Since tumor-specific antibody has been shown to protect from lung metastases after i.v. injection of B16 tumor [22], we tested whether SWHEL mice on a Rag2−/− background would be more resistant to i.v. challenge with 1×106 B16.mHELMCC tumor than their SWHEL-negative Rag2−/− littermates that lack all T and B cells.