IHC of healthy and day 6 post TBI spleen and axillary LN tissues. (A-B) The comparison of spleen tissue stained for CD3⁺ cells in (A) a healthy control (DCAK) to (B) a 5Gyx2 monkey euthanized on day 6 post-TBI (ZI64). Residual lymphocytes (stained with a rabbit polyclonal anti-human CD3 antibody) were observed within the spleen but with a complete disruption of LN architecture in ZI64. (C-D) A similar comparison of axillary LN. These ex vivo data correlates with the SPECT imaging.