title: Developmental interactions of CD4 T cells and thymocytes: age-related differential effects.
abstract: The study was designed to determine whether the developmental potential of immature thymocytes in the thymus is altered in aging, and whether concomitantly present mature T cells have any feedback effect. The strategy was to seed sorted double negative, CD4-CD8-(DN) thymocytes on their own, or in the presence of mature T cells, onto lymphoid depleted fetal thymus (FT) explants, and to examine the resulting T cell subsets. Thymocyte donors were young (2-3 months) and old (24 months) C57BL/6J, Thy1.2 mice and splenocytes were from C57BL/Ka, Thy1.1 mice. The DN cells of the old gave rise to lower values of double positive CD4+CD8+ (DP) cells than those of the young. Cocultures containing a mixture of DN thymocytes and CD4+CD8- splenocytes showed higher CD4+CD8- and DN, and lower DP and CD4-CD8+ levels in the old-donor derived cells, as compared with the young ones. Similar results were obtained with CD4+CD8- thymocytes. In contrast, the presence of CD4-CD8+ splenocytes had no effect on the pattern of DN cell development. Our data indicate that differentiation of CD4/CD8 thymocyte phenotypes is affected by CD4+ cells, in an age-associated differential manner.
authors.affiliation: Department of Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Fridkis-Hareli
authors.forename: R
authors.initials: R
authors.lastname: Mehr
authors.forename: L
authors.initials: L
authors.lastname: Abel
authors.forename: A
authors.initials: A
authors.lastname: Globerson
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D015704:CD4 Antigens / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology*; D016827:CD8 Antigens / Q000097:blood; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D015704:CD4 Antigens; D016827:CD8 Antigens