LACK OF CORRELATION OF ONSET OF LYMPHOMAS AND LEVELS OF MURINE LEUKEMIA-VIRUS IN (AKRXCBA-H-T6CRC) F1

There is some evidence that the incidence of lymphomas in AKR hybrids parallels levels of murine leukaemia virus (MuLV). We originally noted that tumours were much delayed in the (AKR × CBA/H-T6Crc) F1 in spite of high levels of MuLV. The study of this cross has been extended to investigate any association between the level of MuLV with the incidence of lymphomas, any possible influence of maternal factors, and also to learn whether the delay of onset of lymphoma in the F1 is associated with the lack of anti-MuLV antibody activity. Results showed that although lymphomas were seen in reciprocal (AKR × CBA/H-T6Crc) F1 their occurrence was delayed. In contrast to the AKR, where tumours generally develop in the first year, tumours in the F1 occur in the second year of life. There was no difference in tumour incidence between the reciprocal normally derived crosses and crosses obtained following early embryo exchange transplantation. Levels of MuLV in spleen extracts of the F1 tested from 27 weeks onwards were, in general, higher than the parental AKR. However, this was only statistically significant in the (CBA/H-T6Crc × AKR) cross. There was also a higher level of MuLV in this cross when compared with the reciprocal (AKR × CBA/H-T6Crc) F1, although this was not statistically significant. The trend towards a higher level of MuLV associated p30 antigen in the (CBA/H-T6Crc × AKR) F1 was also seen in the reciprocally embryo transplanted progeny, indicating no apparent maternal effect. Finally, and in contrast to CBA/H-T6Crc immunized with Gross AKR virus, no anti-AKR MuLV activity was detected in the sera of the (AKR × CBA/H-T6Crc)F1. © 1979.