TNF-α enhances export of CD4⁺CD8⁺ thymocytes.

<p>Control and 14 days-infected animals were intrathymically injected with FITC dissolved in PBS with or without TNF-α. Twenty-four hours later, recent thymic emigrants (RTEs) were recognized as FITC⁺/CD4⁺/CD8⁺ cells in secondary lymphoid organs (spleen and subcutaneous lymph nodes) by flow cytometry. Empty bars represent the absolute number of FITC⁺ cells (×10³) from PBS injected mice and black bars represent the absolute number of FITC⁺ cells from TNF-α injected animals. Results show that after infection, the numbers of RTEs are clearly enhanced, independently of whether intrathymic injection of TNF-α was applied or not. When considering CD4/CD8-defined subpopulations, we found that intrathymic inoculation of TNF-α further promoted a significant enhancement in the numbers of FITC⁺CD4⁺ and FITC⁺CD4⁺CD8⁺ cell in the spleen, but not in lymph nodes. Data depict a representative experiment of two similar ones; each experiment being done with 5–6 animals/group. Statistically significant differences are indicated as *p<0.05.