Immunohistochemical staining of the thymus, spleen, and mesenteric lymph nodes. Six months after transplantation, various organs were taken, and frozen sections were prepared. Expressions of human CD3 (Vector Blue)/human CD20 (DAB), human CD1a (Vector Blue), human Ki-67 (Vector Blue), and human CD4 (Alexa 488)/human CD8 (Cy3) were evaluated. Original magnification is × 400 for CD4/CD8 images, × 100 for all others.