Differentiation block of prethymic lymphocytes during Moloney-virus-induced lymphoma development associated with a thymic epithelial defect.
Previous cytokinetic studies in Moloney-virus (M-MuLV)-induced lymphomas of BALB/c mice showed an intrathymic maturation block of prethymic lymphocytes derived from hematopoietic tissues. Thymus-cell cultures during the latent period of lymphoma development showed a proportion of nonlymphoid cells (NLC) from uninfected mice of 0.1% (3 days) to 0.002% (20 days), rising in infected mice to 1-2% after 5 weeks. Concomitantly, thymic epithelial cells exhibit progressive degenerative changes in vivo in infected mice with virus replication and in vitro a marked cellular polymorphism with nuclear atypia becomes overt. Immunofluorescence studies of thymopoietin II and serum thymus factor in epithelial cells indicate a marked decrease of these hormones in the epithelial cells from infected mice. These results suggest a functional defect of virus-infected thymic epithelial cells which causes a progressive accumulation of nondifferentiating T-cell precursors.
D000818:Animals; D002454:Cell Differentiation; D046508:Culture Techniques; D004848:Epithelium / Q000473:pathology; D005455:Fluorescent Antibody Technique; D008214:Lymphocytes / Q000473:pathology*; D008223:Lymphoma / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008979:Moloney murine leukemia virus; D013950:Thymus Gland / Q000473:pathology*