Journal: Blood

Article Title: CD8 + T cells are predominantly protective and required for effective steroid therapy in murine models of immune thrombocytopenia

doi: 10.1182/blood-2015-03-635417

Figure Lengend Snippet: Depletion of CD8+ T cells results in more severe thrombocytopenia and impairs responsiveness to steroid therapy in vivo. For the active model, WT mice were transplanted with immunized β3−/− splenocytes with or without depletion of CD8+ T cells. DEX treatment began at day 6. (A) Thrombocytopenia was more severe in mice given CD8+ T cell–depleted splenocytes compared with those transplanted with nondepleted splenocytes as indicated by &&&P < .001. Mice transplanted with CD8+ T cell–depleted immunized β3−/− splenocytes were less responsive to oral DEX compared with mice transplanted with nondepleted splenocytes as indicated by ###P < .001. ***P < .001, nondepleted splenocytes vs nondepleted splenocytes + DEX. N = 8. In our passive mouse model, CD8+ T cells were depleted from WT mice by injection of anti-CD8 mAb (400 μg intravenously) before inducing passive ITP with anti-β3 mAb (9D2, 1 μg intraperitoneally). Platelet counts were not significantly affected by anti-CD8 mAb depletion of CD8+ T cells. DEX was administered (10 mg/kg/day, intraperitoneally, daily) beginning at 4 hours after anti-β3 mAb injection. (B) Thrombocytopenia was more severe in CD8+ T cell–depleted mice compared with those given the anti-β3 integrin mAb alone. N = 6. (C) CD8+ T cell–depleted thrombocytopenic mice were less responsive to DEX compared with mice with normal levels of CD8+ T cells. N = 6. ***P < .001. Mean ± SD.

Article Snippet: CD8 + T-cell purification and transfusion For in vitro suppression assays and adoptive transfer experiments, CD8 + T cells were enriched (>90%) using a CD8 + T-cell enrichment column (StemCell Technologies).

Techniques: In Vivo, Injection

Journal: Blood

Article Title: CD8 + T cells are predominantly protective and required for effective steroid therapy in murine models of immune thrombocytopenia

doi: 10.1182/blood-2015-03-635417

Figure Lengend Snippet: CD8+ T-cell transfusion therapeutically attenuated platelet clearance and enhanced response to DEX in passive murine model of ITP. In the passive model of ITP, mice were injected with anti-β3 integrin mAb (9D2, 1 μg, intraperitoneally) at day 0 and transfused with 106 CD8+ T cells from either WT, naïve β3−/−, or immunized β3−/− mice. Control cells are remaining splenocytes following CD8+ purification. (A) CD8+ T cells significantly increased platelet count in the absence of any DEX treatment. N = 6. *P < .05, **P < .01, ***P < .001 vs PBS. (B) DEX (10 mg/kg) was administered at 4 hours after mAb injection and CD8+ T-cell transfusion. N = 6. *P < .05, **P < .01, ***P < .001 vs PBS or indicated groups. Mean ± SD.

Article Snippet: CD8 + T-cell purification and transfusion For in vitro suppression assays and adoptive transfer experiments, CD8 + T cells were enriched (>90%) using a CD8 + T-cell enrichment column (StemCell Technologies).

Techniques: Injection, Control, Purification

Journal: Blood

Article Title: CD8 + T cells are predominantly protective and required for effective steroid therapy in murine models of immune thrombocytopenia

doi: 10.1182/blood-2015-03-635417

Figure Lengend Snippet: Steroid treatment selectively increased CD8+ Tregs in both the passive and active models of ITP. (A) In the passive model of ITP, mice were injected with anti-β3 mAb (9D2, 1 μg, intraperitoneally) at day 0. In some mice, 10 mg/kg DEX was administered via intraperitoneal injection 4 hours after antibody injection. On indicated days, mice were bled, and different CD8+ subsets were detected via flow cytometry. N = 8 to 10. (B) In the active model, mice were transfused with immunized β3−/− splenocytes on day 0. DEX treatment (oral, 10 mg/kg) or control water was initiated on day 6. Mice were bled on the indicated days, and CD8+ subsets were detected as above. N = 6, *P < .05, **P < .01, ***P < .001. Mean ± SD.

Article Snippet: CD8 + T-cell purification and transfusion For in vitro suppression assays and adoptive transfer experiments, CD8 + T cells were enriched (>90%) using a CD8 + T-cell enrichment column (StemCell Technologies).

Techniques: Injection, Flow Cytometry, Control

Journal: Blood

Article Title: CD8 + T cells are predominantly protective and required for effective steroid therapy in murine models of immune thrombocytopenia

doi: 10.1182/blood-2015-03-635417

Figure Lengend Snippet: CD8+ T cells suppressed platelet apoptosis and clearance in vitro. (A-B) CD8+ T cells from immunized β3−/− mice were added to CD8+-depleted splenocytes and then cocultured with WT platelets. Control has no CD8+ T cells added. (A) After 72 hours, platelets remaining in culture were identified by forward and side scatter characteristics and gated on 7-AAD− and assessed for apoptosis with caspase 3/7 and Annexin V. N = 4. (B) CD8+ T cells from immunized β3−/− mice were cocultured with platelets for 72 hours, and then the remaining platelets in solution were counted, with flow cytometry as events per second. More platelets remained in the coculture system after incubation with CD8+ T cells from immunized β3−/− mice compared with control or naïve β3−/− CD8+ T cells. N = 4. (C) Platelets were labeled with 9D2 primary antibody and FITC anti-mouse IgG. Platelets were then cocultured with macrophages with or without CD8+ T cells. After 24 hours, FITC-positive macrophages were detected by flow cytometry. CD8+, CD8+CD25+, CD8+CD122+, and CD8+CD103+ T cells from immunized β3−/− and WT mice significantly suppressed phagocytosis of platelets by macrophages. Furthermore, the CD8+ T cells from immunized β3−/− mice suppressed phagocytosis more effectively (P < .05). This inhibitory function was also dose dependent (supplemental Figure 4) *P < .05, **P < .01. Mean ± SEM.

Article Snippet: CD8 + T-cell purification and transfusion For in vitro suppression assays and adoptive transfer experiments, CD8 + T cells were enriched (>90%) using a CD8 + T-cell enrichment column (StemCell Technologies).

Techniques: In Vitro, Control, Flow Cytometry, Incubation, Labeling

Journal: Blood

Article Title: CD8 + T cells are predominantly protective and required for effective steroid therapy in murine models of immune thrombocytopenia

doi: 10.1182/blood-2015-03-635417

Figure Lengend Snippet: CD8+ Tregs from immunized β3−/− mice inhibit the adaptive antiplatelet immune response in vitro. For proliferation assays, purified splenic CD8+ T cells or CD8+ Tregs from WT, naïve β3−/−, or WT platelet immunized β3−/− mice were added to CD8+ T cell–depleted splenocytes in the presence of 1 × 107 WT platelets per well to induce T- or B-cell proliferation. Control cells were CD8+-depleted splenocytes with PBS or platelets (PLT) as indicated. Both immunized β3−/− CD8+ T cells and CD8+ Tregs inhibited (A,E) CD4+ T-cell proliferation, (B,F) CD19+ B-cell proliferation, and (C,G) platelet-associated IgG production. (D) Immunized β3−/− CD8+ T cells also inhibited IL-10 cytokine production dose dependently. N = 8. Imm, immunized. *P < .05, **P < .01. Mean ± SEM.

Article Snippet: CD8 + T-cell purification and transfusion For in vitro suppression assays and adoptive transfer experiments, CD8 + T cells were enriched (>90%) using a CD8 + T-cell enrichment column (StemCell Technologies).

Techniques: In Vitro, Purification, Control

Journal: Blood

Article Title: CD8 + T cells are predominantly protective and required for effective steroid therapy in murine models of immune thrombocytopenia

doi: 10.1182/blood-2015-03-635417

Figure Lengend Snippet: CD8+ Tregs from immunized β3−/− mice inhibit CD8+ cytotoxic activity against platelets. Platelets (5 × 106) were cultured with purified 1 × 105 cytotoxic CD8+ T cells (CD8+CD178+) with or without 5 × 105 CD8+ Treg cells (according to the original ratio) for 24 hours. Platelet cytotoxicity was measured with (A) remaining platelet number in supernatant, determined as number of platelets per second counted by flow cytometry69 and (B) caspase 3/7 expression. N = 4. PLT, platelet; CTL, cytotoxic CD8+ T cells. *P < .05, **P < .01. Mean ± SEM.

Article Snippet: CD8 + T-cell purification and transfusion For in vitro suppression assays and adoptive transfer experiments, CD8 + T cells were enriched (>90%) using a CD8 + T-cell enrichment column (StemCell Technologies).

Techniques: Activity Assay, Cell Culture, Purification, Expressing