Fig. 4

Plasmodium berghei ANKA infection induced apoptosis in mice lymphocytes and anti-Tim-3 treatment protected lymphocytes from apoptosis in vitro. (a, b) Necrotic and apoptotic circulatory immune cells at 15 days p.i. The gate strategy of propidium iodide (PI)-positive and annexin V-negative (Q1), PI- and annexin V-positive (Q2), PI- and annexin V-negative (Q3), and PI-negative and annexin V-positive (Q4) cells in lymphocytes (the dot plots marked in red and named lym), non-lymphocytes (the dot plots marked in blue and named non-lym), CD8⁺ T cells (the dot plots marked in purple and named Tc) and CD19⁺ cells (the dot plots marked in red and named B) populations. Histograms comparing the proportion of different kinds of apoptotic cells in lymphocytes, non-lymphocytes, CD8⁺ cells, and CD19⁺ cells. (c, d, and e) Circulatory lymphocytes from healthy mice were incubated with 1 × 10⁵ PbA-infected erythrocytes in the presence of 5 µg/ml of an anti-Tim-3 antibody (lym + PbA + anti-Tim-3), or rat IgG2α κ isotype (lym + PbA + iso), and circulatory lymphocytes from healthy mice were incubated with 1 × 10⁵ PbA-infected erythrocytes as a negative control (lym + PbA), with circulatory lymphocytes from healthy mice as the blank control (lym). The cells were collected after cultivation for 24 h and analyzed by flow cytometry. The gating strategy of PI-positive and annexin V-negative (Q1), PI- and annexin V-positive (Q2), PI and annexin V-negative (Q3), and PI-negative and annexin V-positive (Q4) cells in lymphocytes. Histograms comparing the proportion of early apoptotic cells (Q4). Histograms comparing the proportion of late apoptotic cells (Q2). The results are representative of three independent experiments with five to seven mice in each group per experiment, with data denoting means ± SDs. *P < 0.05, **P < 0.01, ***P < 0.001. Abbreviations: PbA, P. berghei ANKA; Lym, lymphocytes