Figure 5. Selective CD28 blockade modulates recruitment of innate immune cells into allografts.

Thy1.1⁺ OT-I T cells (1 × 10⁴) were adoptively transferred into naive B6 Thy1.2 hosts and infected with Listeria-OVA to generate recipients containing memory OT-I T cells. (A–D) On day 30 after infection, mice received an OVA-expressing skin graft and were treated with 200 μg CTLA-4 Ig or 100 μg anti-CD28 dAb on days 0, 2, and 4 after transplant. Animals were sacrificed on days 5 or 10 after transplant, and skin grafts were harvested and processed for graft-infiltrating leukocytes. (A) Representative flow cytometry plots depicting frequencies of Thy1.1⁺ T cells infiltrating skin grafts (data are gated on CD8⁺ T cells) on day 5. (B and C) Summary data of absolute numbers of graft-infiltrating Thy1.1⁺ T cells on day 5 (B) and day 10 (C) after transplant. (D) Representative flow cytometry plots of frequencies of CD11b⁺ myeloid cells infiltrating skin grafts on day 5, summarized as absolute numbers of cells on day 5 (E) and day 10 (F). *P < 0.05, **P < 0.01 by 1-way ANOVA. dAb, domain antibody.