Abnormal thymic T-cell development in PRR cKO mice. (A) Absolute numbers of T (all CD3⁺), B, macrophage, and dendritic cells from spleens of 7- to 8-week-old mice were determined by flow cytometry. (B) Absolute numbers of naïve (CD44^loCD62L⁺) CD4⁺ and CD8⁺ T cells and γδT cells. (C) Morphology, tissue weight, cellularity, and number of CD3⁺ cells of thymi from 6-week-old mice. (D) Thymocytes from 6-week-old control and cKO mice were analyzed by flow cytometry. The gating strategy for CD4 and CD8 expression is shown. (E) From panel D: the percentage (top) and number (bottom) of DN, ISP, double-positive (DP), CD4 single-positive (SP), CD8 SP, TCRγδ, and regulatory T (Treg) cells.