of Mice: X
Inbr: F89. Albino. Genet: a, B/b, c.
Origin: Unknown, but maintained
by Goldfeder since 1953.
No spontaneous tumours of any kind. They are resistant to the induction
of tumours by urethane, producing only 3% tumours at dose levels that
would induce 80-90% in other strains. Also resistant to tumour induction
by X-rays. Combined X-ray and urethane produces only 6% tumours. The mice
do not produce murine leukaemia virus antigens in their milk, and are
resistant to polyoma virus, Friend leukaemia virus and FBJ osteosarcoma
virus. They also have high immune response against sheep erythrocytes,
pronounced splenic phagocytic activity, high levels of antibody to mammary
tumour virus and a tendency to spontaneous amyloidosis. The low tumour
incidence is attributed to high immune competence and absence of an apparent
oncogenic virus as revealed by electron microscopy (Goldfeder et al., 1966; Goldfeder,
r, 1972). Resistance to carcinogens does not appear to be due
to differences in biochemiceal response to such chemicals (Grantham et al., 1976
A., Kauffman S. L., and Ghosh A. K. (1966) Carcinogenesis in naturally
tumour-resistant mice. X-irradiation versus urethan as a carcinogenic
agent. Brit. J. Cancer 20, 361-374.
(1972) Urethan and X-ray effects on mice of a tumor-resistant strain,
X/Gf. Cancer Res. 32, 2771-2777.
P. H., Mohan L. C., and Weisburger E. K. (1976) Metabolism of N-2-fluorenylacetamide
in X/Gf mice: lack of correlation between biochemical interaction and
carcinogenicity. J. Natl. Cancer Inst. 56, 649-651.
INBRED STRAINS OF MICE
Updated 9 Apr. 1998
MRC Toxicology Unit, Hodgkin Building,
University of Leicester,