Studies On Pathogenicity Of Inner Mongolia Strains IMC₁₀₂₀₀ Of Avian Leukosis Virus Subgroup J

Avian Leukosis Virus Subgroup J (ALV-J) induced Avian Myeloid leucosis (Avian myelcytomatosis, ML). In this study, 11 day-aged meat-type and SPF laying chicken embryos were inoculalated allantoically with strain NMC10200 and SDC2000 of ALV-J respectively. Virus-inoculated chickens and uninfected control chickens were hatched and reared to 278 day and dissected at random in this period, the pathological changes and ultrastructural changes of tissues for typical case were observed, pathogeny and tropism of pathogeny were examined by PCR and immunohistochemistry technology. It showed by pathological results that there were tumours in Virus-inoculated chickens (groups 1-4) and incidence of a disease was 8/10(80.0%), 4/7(57.1%), 5/8(62.5%), 3/10(30.0%) respectively, but there was no tumour in uninfected control chickens (groups 5-6) and incidence of a disease is 0/4(0%), 0/4(0%) respectively. Striking features of Virus-inoculated chickens were moderate to great amboyna tumour neoplasms in inner sternum, synsacrum and kidney cote, distinct enlargement of liver, spleen, kidney, spermary and adrenal gland with offwhiter noduses on surface and plane of section of them. Light microscopically, tumour neoplasms were consisted of eosinophil granulated myelocytes, focal and diffuse tumour cell infiltrations were present in liver, kidney, spleen, lung, adrenal gland, spermary (ovary), pancreas and skelecton. Electron microscopically, severe pathological changes were present in tumour cells and liver cells and 120-150nm virus-like particles were observed in some liver cells. Positive ratio of groups 1-6 by PCR was 8/10(80.0%),3/7(42.9%),6/8(75.0%),3/10(30.0%),0/4(0%),0/4(0%) respectively and consistent with pathological diagnosis. It was demonstrated by immunohistochemistry technology that viral gene expression was remarkable in karyotheca and cytoplasm of tumour cells and cytoplasm of marrow, liver, spleen and kidney cells, but viral gene expression was indistinctive in cytoplasm of lung, adrenal gland, spermary (ovary), and pancreas skelecton cells and inexistent in cerebrum, cerebellum and small intestine. So indicated pathogenicity of Inner Mongolia strains of ALV-J.