Abstract T P221: Effect of CD4 And CD8 T Lymphocytes on Infarct Volume Following Experimental Stroke in Male Splenectomized Mice
We have previously shown profound splenic activation by 6 hours following experimental stroke, resulting in rapid and widespread increased production of inflammatory factors by basal and activated splenocytes in male mice. Our lab and others have also shown a subsequent extensive loss of lymphocytes and increased lymphocyte apoptosis in spleen 12 hours after experimental stroke. Lastly, we and others have shown that splenic immunocytes can contribute to increased brain inflammation and infarct volume. However, it is unclear which splenic immunocyte populations may contribute to the evolving ischemic brain injury. Using a mouse splenectomy model and adoptive cell transfer protocols, we evaluated the effect of different splenic immunocyte populations, specifically CD4 and CD8 T lymphocytes, on infarct volume. Male C57BL/6J mice were splenectomized 14 days before experimental stroke and treated 24 hours before experimental stroke with either vehicle (saline), CD4 T lymphocytes, or CD8 T lymphocytes obtained from GFP reporter mice. Each mouse (n=8-10 per group) then underwent 60 minutes of middle cerebral artery occlusion via intraluminal filament. All mice were euthanized and brains collected at 96 hours of reperfusion. Infarct volume (% corrected contralateral structure) was determined by image analysis of coronal brain slices stained with 2,3,5-triphenyltetrazolium chloride. Adoptive transfer of GFPpositive CD4 (cortex, 44±3%; striatum, 50±2%) or CD8 (cortex, 48±2%; striatum, 53±3%) T lymphocytes in splenectomized male mice did not alter infarct volume compared to vehicle-treated (cortex, 38±4%; striatum, 42±5%) splenectomized males (cortex, p=0.140; striatum, p=0.143). Although adding back CD4 or CD8 T lymphocytes did not appear to alter infarct volume, these immunocyte populations are comprised of both inflammatory and regulatory subtypes. Thus, future studies will evaluate the effect of different CD4 and CD8 subpopulations on ischemic brain outcomes. This study was supported by National Institutes of Health grant NS076013.
Author Disclosures: J. Wang: None. S. Bodhankar: None. X. Yu: None. H. Offner: Research Grant; Significant; R01 NS076013, R01 NS075887, R42 NS065515. S.J. Murphy: Research Grant; Significant; R01 NS076013, R01 NS075887, R21 NS078581, U01 NS062676.
- © 2014 by American Heart Association, Inc.