Exposure to sodium tungstate and Respiratory Syncytial Virus results in hematological/immunological disease in C57BL/6J mice

Abstract

The etiology of childhood leukemia is not known. Strong evidence indicates that precursor B-cell Acute Lymphoblastic Leukemia (Pre-B ALL) is a genetic disease originating in utero. Environmental exposures in two concurrent, childhood leukemia clusters have been profiled and compared with geographically similar control communities. The unique exposures, shared in common by the leukemia clusters, have been modeled in C57BL/6 mice utilizing prenatal exposures. This previous investigation has suggested in utero exposure to sodium tungstate (Na2WO4) may result in hematological/immunological disease through genes associated with viral defense. The working hypothesis is (1) in addition to spontaneously and/or chemically generated genetic lesions forming pre-leukemic clones, in utero exposure to Na2WO4 increases genetic susceptibility to viral influence(s); (2) postnatal exposure to a virus possessing the 1FXXKXFXXA/V9 peptide motif will cause an unnatural immune response encouraging proliferation in the B-cell precursor compartment. This study reports the results of exposing C57BL/6J mice to Na2WO4 in utero via water (15 ppm, ad libetum) and inhalation (mean concentration PM5 3.33 mg/m3) and to Respiratory Syncytial Virus (RSV) within 2 weeks of weaning. Inoculation of C57BL/6J mice with RSV was associated with a neutrophil shift in 56% of 5-month old mice. When the RSV inoculation was combined with Na2WO4-exposure, significant splenomegaly resulted (p=0.0406, 0.0184, 0.0108 for control, Na2WO4-only and RSV-only, respectively) in addition to other hematological pathologies which were not significant. Exposure to Na2WO4 and RSV resulted in hematological/immunological disease, the nature of which is currently inconclusive. Further research is needed to characterize this potential leukemia mouse model.