title: Suppression of endogenous murine leukemia virus by maternal resistance factor.
abstract: Females of the RF and SJL inbred mouse strains transmit to their progeny of both sexes a nonmendelian maternal resistance factor (MRF) able to suppress the expression of endogenous ecotropic murine leukemia virus (E-MuLV). This MRF is demonstrable in crosses with AKR mice by comparing E-MuLV expression in the spleens and thymuses of reciprocal F1 generations. DBA/2 and ST/b mice are MRF negative by these criteria. Neonatal inoculation of E-MuLV-containing spleen extracts gives rise to persistent expression of infectious virus in mice of the MRF- but not the MRF+ strains. However, inoculation of the virus in 30-d-old females of the MRF- strains no longer leads to a state of persistent infection; instead, these females become MRF+ and transmit protection against E-MuLV expression to their progeny by AKR and RF males. The MRF appears to be transmitted to the progeny mainly through the milk, since foster-nursing AKR neonates on RF (but not DBA/2) mothers greatly reduces E-MuLV expression in the progeny. These RF-fostered AKR mice also show a reduced and delayed lymphoma incidence, a finding consistent with the idea that maternally transmitted resistance to E-MuLV expression is the basis for the classic maternal resistance to lymphomagenesis seen in the progeny of RF mothers.
mesh_terms: D000375:Aging; D000818:Animals; D000833:Animals, Suckling; D003433:Crosses, Genetic; D005260:Female; D007113:Immunity, Innate; D009052:Leukemia Virus, Murine / Q000254:growth & development; D007942:Leukemia, Experimental / Q000235:genetics* / Q000382:microbiology; D008223:Lymphoma / Q000235:genetics* / Q000382:microbiology; D008431:Maternal-Fetal Exchange; D051379:Mice; D008806:Mice, Inbred AKR; D008811:Mice, Inbred DBA; D008815:Mice, Inbred Strains / Q000235:genetics*; D010641:Phenotype; D011247:Pregnancy; D013154:Spleen / Q000382:microbiology; D010948:Viral Plaque Assay