T cell‐expressed Ift88 is required for proper thymocyte differentiation in mice

Abstract

Abstract Intraflagellar transport protein 88 (Ift88) is required for the formation of cilia in the thymus and non‐ciliary dependent functions including T cell immune synapse formation. To test the role of Ift88 in T cell development, we performed flow cytometry analysis on thymus and spleen tissue isolated from mice lacking Ift88 in thymic epithelial cells (TECs) or T cells. Analyses indicated that TEC Ift88 deletion had no impact on thymic T cell development and minimal impact on splenic T cells. Analysis of T cells in CaggCreERT2+Ift88 tm1BkymTmG mice indicate that approximately half of DN1 thymocytes are Ift88 deficient 3 weeks post‐tamoxifen induction; Ift88 loss did not impact T cell development at the DN2‐DN4 stage or the CD4+/CD8+ double‐positive (DP) thymocyte stage. However, survival of Ift88 deficient T cells was significantly reduced at the single‐positive (SP) thymocyte stage, as was the number of CD4+ and CD8+ T cells in spleen and kidney. Despite preferential survival of Ift88‐proficient cells, the total number of T cells the in spleen and kidney was minimally impacted by Ift88 loss. These data suggest Ift88 is required for differentiation of DP thymocytes into SP thymocytes and that Ift88 proficient T cells can compensate for deficient cells to fill the open niche.

Keywords

• thymocyte development
• thymus