title: Component of strain MC29 avian leukosis virus with the property of defectiveness.
abstract: Three clones of morphologically altered cells (L(-)MC29) of singular properties were isolated from MC29 (subgroup A) leukosis virus-infected chick embryo cells. Supernatant fluids from cultures of the cloned cells produced no transforming or interfering activity on chick embryo cells susceptible to known avian leukosis-sarcoma viruses. No virus associated with the cells was demonstrable by fluorescent-antibody staining or by electron microscopy. All L(-)MC29 clone cells were activated, however, by four strains of Rous-associated viruses (RAV) representative of A, B, C, and D subgroup avian leukosis viruses and by two strains of MC29 virus. Virus L(-)MC29 cells activated by superinfection with RAV-1 and RAV-2 was characterized by helper-dependent and helper-independent properties. These findings suggest that the strain MC29 leukosis virus, or a component thereof, possesses properties of defectiveness similar to those of the Bryan high-titer Rous sarcoma virus.
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D001354:Avian Leukosis Virus / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification*; D001358:Avian Sarcoma Viruses / Q000254:growth & development; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002642:Chick Embryo; D002999:Clone Cells; D003168:Complement Fixation Tests; D046508:Culture Techniques; D003673:Defective Viruses / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification*; D005455:Fluorescent Antibody Technique; D008858:Microscopy, Phase-Contrast; D009500:Neutralization Tests; D011784:Quail; D012526:Satellite Viruses / Q000254:growth & development; D013194:Staining and Labeling; D014762:Viral Interference; D014779:Virus Replication
chemical_list: D000956:Antigens, Viral