Research Paper Volume 4, Issue 9 pp 606—619

Figure 3. Comparison of competence for thymic T-lymphopoiesis from aged- and young-LPCs’ in competitive repopulation of grafted fetal thymus. (A) Results of competitive repopulation of grafted fetal thymus by “young and old” or “old and young” natural thymus-seeding cells from the first and second hosts. Left panel shows % T-lineage thymocytes (gated on DP, CD4⁺ and CD8⁺ SPs) in the grafted thymus naturally seeded by young (~2 month old, circles) and old (22 months old, triangles) BM progenitors in the different seeding orders (initial seeding: filled circles or triangles; subsequent/second seeding: open circles or triangles). Each triangle or circle represents one animal. An unpaired Student's t-test shows p > 0.05 (no significant). The table in the A panel shows absolute cell numbers per grafted lobe (each host mouse was grafted with 2-3 fetal thymic lobes, n = animal number). (B) A representative result of differentiated CD4⁺ and CD8⁺ T cells from the grafted fetal thymic lobes (bottom panels). The thymocytes are derived from first and second seeded young- and old-BM progenitors, identified by CD45.1 and CD45.2 congenic markers (top panels).