IL-7 and common gamma chain–associated signals are dispensable for MHCII expression by cTECs.

(A-B) Bone marrow chimeras were generated with wild-type bone marrow and either wild-type or IL-7R–deficient recipients. (A) Reconstituted thymuses from wild-type or IL-7R–deficient recipients contain the same absolute numbers of thymocytes (4.5 × 10⁷ cells in both thymuses). Thymic subpopulations are strictly identical (compare left and right panels). (B) Total cell counts were identical in the spleens of the wild-type and IL-7R–deficient recipients (5.4 × 10⁷ and 5.5 × 10⁷ cells, respectively). Left and right panels show identical proportions of CD4⁺ and CD8⁺ T cells in the 2 spleens. (C) A c-kit, γc-deficient thymus transplanted under the kidney capsule of a nude mouse generates CD4⁺, CD8⁺, and CD4⁺CD8⁺ thymocytes in normal proportions. Photographs show the similar size of wild-type and c-kit, γc-deficient thymuses transplanted into the nude hosts.