Transmission of Mouse Leukemia Virus Through Milk of Virus-Injected C3H Female Mice.

Abstract

C3H female mice inoculated within a few days after birth with passage A leukemic filtrates, were subsequently mated to virus-injected, or to non-injected, C3H males. Litters born to such parents were exchanged with those born at about the same time to normal, non-injected C3H mice. Out of 25 C3H mice born to normal C3H parents, but foster-nursed by virus-injected C3H females, 20 (80%) developed leukemia at 31/2 to 5 1/2 months of age. Out of 27 mice born to virus-injected mothers, but foster-nursed by normal C3H females, only 4 (15%) thus far developed leukemia at 4 1/2 to 6 months of age. These results indicate that the leukemic virus was transmitted through the milk of nursing females; the latter, however, had leukemia at least part of the time they were nursing. It remains to be determined whether healthy, but virus-carrying, females could also transmit the virus in their milk. Under our experimental conditions, foster-nursing by healthy C3H females of offspring born to virus-injected C3H mothers, reduced the incidence, and possibly delayed, but did not entirely prevent, the development of leukemia.