title: Development of fetal thymocytes in organ cultures. Effect of interleukin 2.
abstract: Most fetal thymocytes from 14-d mouse embryos are Thy-1+, L3T4-, Ly-2-, and express the receptor for interleukin 2 (IL-2). The development of thymocytes has been followed in fetal thymus organ cultures. When fetal thymus from 14-d embryos were cultured for a 6-d period, thymocytes increased in number 20-40-fold, and 95% became Thy-1+, L3T4+, Ly-2+. The addition of IL-2 to organ cultures of 14-d fetal thymus inhibited, in a dose-dependent manner, cell proliferation and the appearance of Thy-1+, L3T4+, Ly-2+ thymocytes. The addition of IL-2 also resulted in the appearance of a population of cells that were cytotoxic for syngeneic and allogeneic fetal thymocytes and syngeneic tumour targets. While the events that lead to the expression of the IL-2 receptor on 14-d fetal thymocytes are unknown, IL-2 in fetal thymus organ cultures inhibits the normal maturation of fetal thymocytes and raises the question of whether the cytotoxic cells that appear reflect selection through an alternative pathway of development.
mesh_terms: D000818:Animals; D002455:Cell Division; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D005260:Female; D005333:Fetus / Q000276:immunology*; D005865:Gestational Age; D007376:Interleukin-2; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009924:Organ Culture Techniques; D010641:Phenotype; D011971:Receptors, Immunologic / Q000032:analysis; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology; D013950:Thymus Gland / Q000166:cytology
chemical_list: D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2