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In vivo selection of two agents differing in hepatoma-inducing activity from strain MC29 avian leukosis virus
Abstract:
MC29 virus induces acute leukemia (myelocytomatosis) and primary tumors of liver (hepatomas) in turkey poults. By in vivo passages two viruses were selected; designated "liver" and "bone marrow" variants, differing in hepatoma-inducing activity. The "liver" variant induces hepatoma and acute leukemia, the "bone marrow" variant induces acute leukemia. The variants differ in leukemogenic activity. The "bone marrow" variant induces high grade leukocytosis, while the "liver" variant causes lymphocytosis and heteropenia. The variants also induce the appearance of primitive myeloid cells in the blood. The kinetics of accumulation of viral gs protein (p27) and the presence of viruses inducing hepatoma and leukemia were studied in organs of infected turkeys. The differences between the variants showed no relationship with their selective reproduction capacity in liver and/or bone marrow cells. The results obtained suggest that different viral particles are responsible for the induction of leukemia and hepatoma.
Insights
MC29 virus causes acute leukemia and liver tumors in turkeys. Two variants, "liver" and "bone marrow," show distinct tumor-inducing and leukemogenic activities, suggesting different viral particles may cause leukemia and hepatoma.
Area of Science:
- Oncology
- Virology
- Immunology
Background:
- MC29 virus is known to induce acute leukemia (myelocytomatosis) and primary liver tumors (hepatomas) in turkey poults.
- In vivo passages led to the selection of two distinct viral variants: a "liver" variant and a "bone marrow" variant, differing in their ability to induce hepatoma.
Purpose of the Study:
- To investigate the distinct oncogenic activities of the "liver" and "bone marrow" variants of MC29 virus.
- To analyze the differences in leukemogenic potential and cellular responses induced by each variant.
- To examine the kinetics of viral protein (p27) accumulation and the presence of oncogenic viruses in infected turkey organs.
Main Methods:
- In vivo selection of viral variants through serial passages in turkey poults.
- Assessment of tumor induction (hepatoma) and leukemogenesis (leukocytosis, lymphocytosis, heteropenia) by each variant.
- Quantification of viral gs protein (p27) and detection of oncogenic viruses in liver and bone marrow tissues.
Main Results:
- The "liver" variant induces both hepatoma and acute leukemia, while the "bone marrow" variant induces only acute leukemia.
- The variants exhibit differential leukemogenic activity, with the "bone marrow" variant causing high-grade leukocytosis and the "liver" variant causing lymphocytosis and heteropenia.
- Both variants lead to the appearance of primitive myeloid cells in circulation, but differences in oncogenic activity did not correlate with selective viral replication in liver or bone marrow cells.
Conclusions:
- The distinct oncogenic profiles of the MC29 virus variants suggest that separate viral particles may be responsible for the induction of leukemia and hepatoma.
- Further research is warranted to elucidate the specific mechanisms by which different viral components contribute to distinct oncogenic outcomes.