Pathologic and Virologie Studies of Tumors Induced in Mice by Two Strains of Murine Sarcoma Virus<xref ref-type="fn" rid="FN2">2</xref>

Abstract

Neonatal Prince Henry mice were inoculated by various routes with 2 concentrations of murine sarcoma virus (Moloney)—MSV(M)—and murine sarcoma virus (Harvey)—MSV(H). Stock MSV(M), inoculated intramuscularly, induced large tumors that uniformly killed the mice. A tenfold dilution of MSV(M) was inoculated intramuscularly, subcutaneously, or intraperitoneally. All animals inoculated subcutaneously had prolonged survival, and a proportion (30%) of those inoculated intramuscularly had prolonged survival. One-third of the long-surviving mice died of lymphocytic leukemia without detectable solid tumor. Historically, the MSV(M)-induced lesions were reactive, consisting of inflammation and repair involving mesenchymal cells. In some lesions, endothelial cells were stimulated to produce slight vasoformation. In the mice surviving for longer periods, there was transition from the typical lesion to fibrous scar tissue, and, at the same time, there were active lesions in the abdominal and chest walls. Infectious MSV(M) was detected in the tumor, spleen, and plasma of these mice. Cells from MSV(M)-induced tumors could not be established in culture. Inoculation by all routes of stock and tenfold diluted MSV(H) resulted in rapid death, with only 3 of 16 mice inoculated subcutaneously surviving for more than 50 days. Histologically, the tumors were intensely vasoformative and very suggestive of angiosarcoma. Many mice had hemorrhagic lesions in the brain. The spleens showed proliferation of reticulum cells with associated erythroblastosis, often leading to splenic rupture and hemoperitoneum. Cells from MSV(H)-induced tumors could be established in culture, with continuous release of MSV(H). It is concluded that Prince Henry mice respond differently to the 2 strains of MSV. These results are discussed in relation to other studies using different strains of mice.