A comparative endpoint study of lesions induced by MoMuSV-m1, MoMuSV-HT1, MoMuSV-124 and MoMuSV-349.

Different MoMuSVs produced predictable clinical, gross, and histologic similarities and differences when inoculated into susceptible hosts intraperitoneally. The neoplasms induced by MoMuSV-124 and MoMuSV-349 were histologically indistinguishable. The distribution of the neoplasms was the most widespread in these two groups. Histologically, the neoplasms induced by MoMuSV-124 and MoMuSV-349 were best described as angioproliferative. The neoplasms induced by MoMuSV-HT1 were most accurately described as fibrosarcomas. Histologically, the neoplasms induced by MoMuSV-m1 had characteristics common to neoplasms induced by MoMuSV-124 and MoMuSV-349, but with a less prominent vascular component. All mice inoculated with these MoMuSVs had moderate to severe thymic atrophy. The degree of thymic atrophy associated with both MoMuSV-124 and MoMuSV-349 was histologically more severe than that associated with MoMuSV-m1 and MoMuSV-HT1. Both MoMuSV-HT1 and MoMuSV-m1 had infiltrates of primitive myeloid cells within the spleen. In the case of MoMuSV-m1, there was an apparent leukaemia with infiltrates of similar cells within the bone marrow. With MoMuSV-HT1, these primitive cells were confined to the spleen. In summary, this study demonstrated that some of the different strains of MoMuSV (with the exception of MoMuSV-124 and MoMuSV-349), induced histologically distinct lesions in BALB/c mice.