Transmission of Ak Leukemic Agent into Newborn Mice of the C57 Brown/cd Inbred Line.

Abstract

Cell suspensions prepared from Ak leukemic donors were inoculated into newborn C57BR/cd mice. Of 33 mice inoculated when less than 2 days old, 29 developed leukemia within 2-4 weeks. Of 61 inoculated when less than 14 days old, 14 developed leukemia, but none of 17 injected at 20-24 days of age. Fifty-three adult C57BR/cd mice over 2 months old were inoculated with large doses of Ak leukemic cell suspensions, and all were resistant. Leukemia developing in suck- ling C57BR/cd mice as a result of implantation of Ak leukemic cells, could be readily-grafted back to adult mice of the donor Ak strain, but not into those of the recipient C57BR/cd line. Centrifuged (7000 x g) Ak leukemic extracts were inoculated into 71 newborn C57BR/cd mice (average age 6 hours), and 44% of them developed leukemia at an average age of 9.6 months. Filtered (Selas) Ak leukemic extracts were inoculated into 42 C57BR/cd mice at an average age of 7 hours, and 33% of them developed leukemia at an average age of 12.3 months. Forty-three litter-mates serving as controls, were inoculated simultaneously with heated (67[degree]-80t for 0.5 to 1 hour) Ak leukemic extracts, and 3 were left untreated, but none developed leukemia. Cell suspensions prepared from those C57BR/cd mice that developed leukemia as a result of inoculation of either centrifuged or filtered Ak leukemic extracts, reproduced, in most instances, within a few weeks, acute leukemia, when transplanted into adult mice of the C57BR/cd (recipient) line, but could not be grafted, with rare exceptions, to adult mice of the Ak (donor) strain. Twenty-two C57BR/cd males and females, that were inoculated with Ak leukemic extracts within a few hours after birth, were mated after they reached sexual maturity and in good health. Among their 147 untreated offspring, 10 have thus far developed leukemia at 7-17 months, suggesting transmission of leukemic agent from inoculated parents to untreated offspring. When, in previous experiments, filtered Ak leukemic extracts were inoculated into newborn C3H mice, some of the inoculated animals developed luekemia, and others developed parotid gland carcinomas. When, however, filtered Ak leukemic extracts were inoculated into C57BR/cd mice, typical leukemia developed in some of them, but none developed salivary gland carcinoma.