Durable mixed porcine and human chimerism in NOD/SCID-Tg mice receiving porcine BM transplants and subsequent human Thy/Liv implants. (A) Porcine hematopoietic chimerism in the white blood cells (WBCs) and BM of NOD/SCID-Tg mice that received porcine BM transplants alone (○) or porcine BM transplants plus human Thy/Liv grafts (•) at week 20 after human Thy/Liv transplantation. Each symbol represents an individual animal. Horizontal lines indicate the mean chimerism level for each group of mice. (B) Kinetics of human chimerism in the PBMCs of NOD/SCID-Tg mice given transplants with porcine BMCs and human Thy/Liv tissues (mean ± SD; n = 17). (C) Peripheral blood cells were collected from NOD/SCID-Tg mice that received porcine BM transplants alone (pBMT, n = 6), human Thy/Liv alone (HuThy/Liv, n = 8), or porcine BM transplants plus human Thy/Liv (n = 17) at the indicated times after human Thy/Liv implantation, and stained with various combinations of antihuman (CD45, CD3, CD4, and CD8), antipan pig tissue (Pan pig), and antimouse CD45 (mCD45) mAbs. Shown are representative FCM profiles. (D) FCM profiles showing porcine and human chimerism in the spleen and BM of NOD/SCID-Tg mice given transplants of porcine BMCs plus human Thy/Liv tissues at week 20 after human Thy/Liv implantation. (E) Percentages (means ± SD) of human class I⁺ and CD3⁺ cells in the spleen and BMCs of NOD/SCID-Tg mice that received porcine BM transplants plus human Thy/Liv grafts (□; n = 17) or human Thy/Liv tissues alone (▪; n = 8) at week 20 after human Thy/Liv implantation. (F) Expression of human CD45RA on gated human CD4⁺ cells. Black and gray histograms are staining profiles of anti-CD45RA and isotype control mAbs, respectively. The percentages (means ± SD) of CD45RA⁺ cells in the gated human CD4⁺ cell population were comparable between HuThy/Liv alone and pBMT plus HuThy/Liv groups (P = .25 and P = .17 for PBMCs and spleen, respectively).