Fig. 3: TAM receptor-mediated efferocytosis of proapoptotic T cells from infected mice.

a BMDMs from WT, Axl^−/− and Mer^−/− mice were cocultured in triplicate with splenic T cells from normal (open circles) or T. cruzi-infected (closed circles) WT mice. After 48 h, nonadherent cells were counted, and cell recovery was calculated by using naïve T cells as controls. b T cells from infected mice were cultured in the absence (open circles) or presence (closed circles) of BMDMs from WT, Axl^−/− and Mer^−/− mice. Cell recovery was calculated based on T cells cultured in the absence of macrophages as 100% controls. c T cells from infected mice were cultured in the presence of BMDMs from WT (closed triangles), Axl^−/− (open triangles) and Mer^−/− (closed squares) mice. c, d T lymphocytes were labelled with anti-CD4, anti-CD8, Annexin V, and 7-AAD for evaluation of AnV⁺ and 7-AAD⁺ dead cells. Analyses were performed in gated CD4 and CD8 T cells. e, f BMDMs were cocultured in triplicate with T cells from T. cruzi-infected WT mice in the absence (closed circles) or presence (open squares) of the TAM receptor inhibitor Mer-Ig. e After 24 h, T cells were collected, counted, and labelled with anti-CD8 and 7-AAD for evaluation of 7-AAD⁺ dead cells. f BMDMs were treated with CFSE-labelled T cells for 1 h and then analysed for CD11b⁺ singlets as macrophages that internalized CFSE⁺ cells. Dotted control lines refer to e T cells cultured alone, and f macrophages cultured with medium only. The means and SEM of n = 3 technical replicates are represented. Significant differences between different macrophages are indicated for ^*P < 0.05, ^**P < 0.01, ^***P < 0.001, and ^****P < 0.0001, as analysed by ANOVA with Tukey’s posttest or by ANOVA followed by Bonferroni posttest of selected pairs of data (macrophages cocultured with T cells in the absence of treatment versus those treated with Mer-Ig). The results are representative of 3 independent experiments in a, b, and c. Panels e and f refer to 2 separate experiments.