Immune suppression or enhancement by CD137 T cell costimulation during acute viral infection is time dependent
J. Clin. Invest. Benyue Zhang, et al. 117:3029 doi:10.1172/JCI32426 [Go to this article.]

Figure 3
Anti-CD137 induced CD8⁺ T cell activation. Spleens from groups of 5 LCMV-infected anti-CD137– or rat IgG–injected mice were collected on day 4 (A and B) or on day 8 P.I. (C and D), and the numbers of CD44^hiCD62L^lo/– CD4⁺ T cells (A and C) and CD44^hiCD62L^lo/– CD8⁺ T cells (B and D) were counted following FACS analysis. (E) Groups of 4 C57BL/6 CD45.1 PepBoy mice were injected i.v. with 1 × 10⁶ CFSE-labeled C57BL/6 CD45.2⁺ P14 LCMV TCR-transgenic CD8⁺ T cells and an equal number of CFSE-labeled C57BL/6 CD45.2⁺ SMARTA LCMV TCR-transgenic CD4⁺ T cells. The mice were then infected i.p. with 2 × 10⁵ PFU LCMV Armstrong and injected i.p. 24 hours later with 200 μg anti-CD137 or rat IgG. On days 2 and 3 P.I. the mice were euthanized and splenic CD45.2CD8⁺ T cells and CD45.2CD4⁺ T cells were gated during FACS analysis and their CFSE content measured. (F) Spleens from groups of 4 C57BL/6 mice reconstituted with CFSE-labeled CD4⁺ and CD8⁺ TCR-transgenic T cells infected with LCMV Armstrong and injected with 200 μg of either rat IgG (dotted lines) or anti-CD137 (solid lines) were collected on the indicated days, stained with fluorochrome-conjugated mAbs specific for CD45.2, CD4, and CD8, and analyzed by FACS and trypan blue exclusion to determine the number of viable cells of each lineage.