SPONTANEOUS DEVELOPMENT OF PLASMACYTOMAS IN A SELECTED SUBLINE OF BALB CJ MICE/

Sixty per cent of BALB/cAnPt mice injected intraperitoneally (i.p.) wi th tetramethylpentadecane (pristane) develop plasmacytomas (PCs), wher eas less than 10% of BALB/cJ develop such tumours. Most other mouse st rains are completely resistant. Resistance is dominant over susceptibi lity in F1 hybrids between BALB/cAnPt and the resistant non-BALB/c str ains, suggesting that susceptibility may be due to some genetic defect . (BALB/cAnPtxBALB/cJ)F1 hybrids have a PC incidence of 36-42%. Previo usly, BALB/cJ has been shown to harbour at least one resistance gene ( Potter et al., Genomics 1988, Vol. 2, pp. 257-262). On the assumption that BALB/cJ may contain a segregating resistance gene, we crossed BAL B/cJ females with pristane-pretreated BALB/cJ males that were found to be carrying PC cells intraperitoneally 5-7 months after pristane trea tment. After two selective crosses, 62% of the BALB/cJ subline BALB/cM 2/22 developed PC after pristane and 52% after pristane followed by Ab elson virus, while unselected controls had an incidence of 11% and 0%, respectively. Moreover, six spontaneous plasmacytomas developed in un treated females of the selected colony. Five of these carried T(12; 15 )(F2; D2/3) translocations. The sixth had a T(1; 10)(G; C1) translocat ion and an interstitial duplication of segment (C1/E3) on one chromoso me 5. It may be concluded that pristane treatment is not a prerequisit e for the induction of the PC associated Ig/myc translocations. (C) 19 97 Elsevier Science Ltd.