Figure 4. Increased T cell immunity of TIPE2 knockout mice.

A-C. Increased T cell immune responses to LCMV infection. TIPE2^−/− mice and their littermate controls (n=6), 5–6 weeks of age, were injected i.p. with 10⁶ LCMV Armstrong, and sacrificed 8 days later. Splenocytes were collected, stained with anti-CD8 and LCMV-specific D^b/gp33-tetramer, and examined by flow cytometry (A) (Ochsenbein et al., 1999). The total numbers of CD8⁺, D^b/gp33-tetramer⁺ (tet⁺) cells per spleen were presented in 4B. Splenocytes were also cultured with LCMV-gp33–41 peptide (1μM) for 48 hours, and the concentrations of IFN-γ in the supernatants were determined by ELISA (C). Results are representative of two independent experiments. D. Increased reactivity of TIPE2 knockout T cells to TCR stimulation. CD4⁺ T cells were purified from spleens of 4–5-week-old wild type (n=5) or TIPE2-deficient littermates (n=5), and stimulated with indicated amounts of plate-bound anti-CD3 and 1 μg/ml of soluble anti-CD28 mAbs. Cytokine concentrations in the culture supernatants were determined by ELISA at 24 hr, and proliferation was measured by ³H-thymidine incorporation [presented as count per minute (CPM)] at 48 hr. Data shown are means and SD, and are representative of three experiments. No significant differences were detected between knockout and control groups in terms of the number and percentage of dead cells as determined by annexin V staining.