Figure 1.
Pediatric thymus from cardiac surgery can be implanted into NSG mice as an alternative to fetal thymus
(A) Thymus retrieved from 3-day-old to 5-year-old donors undergoing cardiac surgery was cut into 1-mm2 pieces and put on a gelfoam sponge culture system for 7–21 days.
(B) Two to three pieces were engrafted into the quadriceps muscle of NSG mice along with an i.v. injection of 1–2 × 105 umbilical cord blood CD34+ (see Video S1).
(C) Left panels: representative thymic tissue sections from both BLT and CCST mice recovered at 30 weeks post humanization (left panels). Hematoxylin-phloxin-safran staining shows that engrafted tissues were well inserted in the surrounding tissues (arrow, in the kidney for BLT and in the quadriceps muscle for CCST). Both models showed typical thymus structure with cortex (C), medulla (M), and Hassall’s corpuscles (H). Immunochemistry staining shows the presence of hCD3+ (T cells) and hCD19+ (B cells). The thymus displayed medullar and cortical arrangement with thymic epithelium expressing cytokeratin 19. Middle panels: spleen tissues from both BLT and CCST displaying white (W) and red (R) pulp, T cells (hCD3+), B cells (hCD19+), and monocytes (hCD68+), as well as megakaryocyte (open arrowhead). Right panels: mesenteric lymph nodes (MLN) recovered from BLT and CCST mice displayed germinal centers with B and T lymphocyte zones.