Figure 4.

CD (cluster of differentiation) 84 expression on CD4⁺ T cells and platelets is required to promote infarct growth after transient middle cerebral artery occlusion (tMCAO).

Representative triphenyltetrazolium chloride–stained 2-mm brain slices of (A, top to bottom) and infarct volumes 24 h after tMCAO (B) of Rag1^−/− mice (n=9), Rag1^−/− mice with adoptive transfer of WT (n=10), or Cd84^−/− CD4⁺ T cells (n=11; P=0.0050) at day 1 before surgery, Cd84^−/− mice with adoptive transfer of WT (n=8) or Cd84^−/− CD4⁺ T cells (n=8) at day 1 before surgery, and mice specifically lacking the expression of CD84 on platelets (n=11) compared with control mice (n=8; P=0.0409), at day 1 after tMCAO. Bar=1 cm. C, Quantification of brain-infiltrating CD4⁺ T lymphocytes in the ipsilateral hemisphere on day 1 after tMCAO of Cd84^{fl/fl, Cre-neg} and Cd84^{fl/fl, Pf4-Cre} mice (n=6 mice per group; P=0.0368). Statistical significances analyzed by Mann-Whitney U test. *P<0.05. AT indicates adoptive transfer.