Induction of Lymphocytic Leukemia,

SUMMARY-Simian virus 40 (SY40), an oncogenic DNA virus, was inoculated intravenously into 3-week-old weanling male Syrian golden hamsters. By 3 ~ months, 85-95 % of the virus-inoculated animals developed neoplasms, whereas all uninoculated controls and animals that received a mixture of SV 40 and anti-SV 40 serum were Free of neoplastic disease. The induced neoplasms were lymphocytic leukemia, lymphosarcoma, reticulum cell sarcoma, osteogenic sarcoma, and anaplastic sarcoma. Evidence For an etiologic role of SY.40 was obtained both indirectly, by neutralizing the in vivo oncogenic effect of the virus by anti-SY 40 serum, and directly, by demonstrating: a) SY 40 T ("tumorlt) antigen in parenchyma I cells of all tumors tested, b) antibody production against SY40 T antigen in adult hamsters with primary tumors or tumor transplants, c) SY 40 virogeny by neoplastic cells in vitro when grown in the presence of susceptible indicator grivet monkey kidney cells, and d) absence of serologic markers for oncogenic RNA viruses in 4 SY.40-T-positive lymphoid neoplasms tested. This is the first time an oncogenic DNA virus, other than a member of the herpes group, has been shown to induce lymphocytic leukemia, lymphosarcoma, and reticulum cell sarcoma.-J Natl Cancer Inst 50: 1347-1365, 1973. ONCOGENIC or tumor-producing viruses are grouped by the chemical nature of their geneti