OVEREXPRESSION OF V-ABL UNIQUELY COOPERATES WITH C-MYC DYSREGULATION IN INDUCTION OF PLASMA-CELL TUMORS, BYPASSING THE NEED FOR T-LYMPHOCYTIC HELP AND OVERCOMING T-LYMPHOCYTIC INTERFERENCE

We have investigated the effects of T lymphocytes on induction of mous e plasma cell tumors. We show that ABL-MYC, a plasmacytomagenic retrov irus that constitutively expresses v-abl and c-myc, is able to induce plasmacytomas in 100% of athymic BALB/c mice, with or without intraper itoneal pristane pretreatment. Other induction regimens are ineffectiv e under these conditions, indicating that the combination of v-abl and c-myc oncogenes is uniquely able to transform plasma cells in mice th at are deficient in T lymphocytes. Furthermore, in the absence of pris tane, ABL-MYC-infected athymic congenics developed plasmacytomas in ha lf the time required for euthymic BALB/c mice, suggesting that T lymph ocytes can have a negative effect and can retard, but not totally inhi bit, the outgrowth of plasmacytomas. This phenomenon could not be appr eciated in other regimens of plasmacytoma induction, because only ABL- MYC is sufficient to induce plasmacytomas in athymic mice or in euthym ic mice in the absence of pristane pretreatment. (C) 1996 Wiley-Liss, Inc.