title: Pathogenicity of two recombinant avian leukosis viruses.
abstract: We have recently described the isolation and molecular characteristics of two recombinant avian leukosis subgroup J viruses (ALV J) with an avian leukosis virus subgroup A envelope (r5701A and r6803A). In the present study, we examined the role of the subgroup A envelope in the pathogenesis of these recombinant viruses. Chickens of line 151(5) x 7(1) were inoculated at 1 day of age with r5701A, r6803A, Rous-associated virus type 1 (RAV-1), or strain ADOL-Hcl of ALV-J. At 2, 4, 10, 18, and 32 wk postinoculation (PI), chickens were tested for avian leukosis virus (ALV)-induced viremia, shedding, and neutralizing antibodies. All except one chicken inoculated with the recombinant viruses (98%) developed neutralizing antibodies by 10 wk PI compared with only 16% and 46% of the ADOL-Hcl and RAV-1-inoculated birds, respectively. ALV-induced tumors and mortality in the two groups inoculated with recombinant viruses were different. The incidence of tumors in groups inoculated with r5701A or RAV-1 was 100% compared with only 9% in the groups inoculated with r6803A or ADOL-Hcl. The data suggest that differences in pathogenicity between the two recombinant viruses might be due to differences in the sequence of the 3' untranslated region (presence or absence of the E element), and, therefore, not only the envelope but also other elements of the viral genome play an important role in the pathogenesis of ALV.
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Avian Disease and Oncology Laboratory, 3606 East Mount Hope Road, East Lansing, MI 48823, USA.
authors.forename: Blanca
authors.initials: B
authors.lastname: Lupiani
authors.forename: Susan M
authors.initials: SM
authors.lastname: Williams
authors.forename: Robert F
authors.initials: RF
authors.lastname: Silva
authors.forename: Henry D
authors.initials: HD
authors.lastname: Hunt
authors.forename: Aly M
authors.initials: AM
authors.lastname: Fadly
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D001353:Avian Leukosis / Q000276:immunology / Q000821:virology*; D001354:Avian Leukosis Virus / Q000145:classification / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity*; D002472:Cell Transformation, Viral; D002645:Chickens / Q000276:immunology / Q000821:virology; D005260:Female; D008297:Male; D012313:RNA / Q000235:genetics*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism; D014766:Viremia; D014774:Virulence; D017201:Virus Shedding
chemical_list: D000914:Antibodies, Viral; C039919:RNA, recombinant; D014759:Viral Envelope Proteins; D012313:RNA