Dermal Microvascular Injury in the Human Peripheral Blood Lymphocyte Reconstituted-Severe Combined Immunodeficient (HuPBL-SCID) Mouse/Skin Allograft Model Is T Cell Mediated and Inhibited by a Combination of Cyclosporine and Rapamycin

Abstract

We have analyzed the mechanism of human endothelial injury in a human peripheral blood lymphocytesevere combined immunodeficient (huPBL-SCID) mouse/human skin graft model of allograft injury and examined the effect of immunosuppressive drugs on this process. In this model , split-thickness human skin containing the superficial dermal microvessels was grafted onto immunodeficient C.B-17 SCID or SCID/beige mice and allowed to heal. Human peripheral blood mononuclear cells (PBMCs) allogeneic to the skin , when subsequently introduced by intraperitoneal injection , caused destruction of the human dermal microvasculature by day 16 , evident as endothelial cell sloughing and thrombosis. In the same specimens , mouse microvessels that invaded the human skin graft were uninjured. Human microvascular cell injury was accompanied by a mononuclear cell infiltrate consisting of approximately equal numbers of human CD4؉ and CD8؉ T cells , some of which contained perforin-positive granules. We found no evidence of human natural killer cells and noted occasional human , but not mouse , macrophages at a frequency indistinguishable from that resident in skin on animals not receiving human PBMCs. These human T cell infiltrates did not extend into adjacent mouse skin. Human immunoglobulin G antibody was detected in the blood and was diffusely present throughout mouse and human tissues in SCID mice receiving PBMCs. Mouse C3 was detected on human dermal vessels in both unreconstituted control animals and those that received PBMCs. Blood and tissues from mice injected with PBMCs depleted of B cells showed no human immunoglobulin, but circulating CD3؉ cells were detected by flow cytometry at levels comparable with those of animals receiving whole PBMCs. Significantly, skin graft infiltration by human T cells and human dermal microvascular injury were equivalent in the B cell-depleted and whole-PBMC-reconstituted mice. Mice inoculated with PBMCs depleted of CD8؉ T cells developed microvascular injury and infiltrates containing perforin-expressing CD4؉ T cells. These data suggested a cytolytic T celldependent mechanism of microvessel injury. We then tested the ability of T cell immunosuppressants, cyclosporine and rapamycin, to attenuate vessel damage.

Anti-CD11a Ameliorates Disease in the Human Psoriatic Skin–SCID Mouse Transplant Model: Comparison of Antibody to CD11a with Cyclosporin A and Clobetasol Propionate

“…In parallel with growth inhibition, Cyclosporin A reduces the production of pro-inflammatory effector molecules by keratinocytes (Iversen et al, 1996;Kaplan et al, 1995;Won et al, 1994). Fibroblasts, endothelial cells, and antigen-presenting cells may also be important targets of Cyclosporin A in psoriasis (Fukuoka et al, 1998;Murray et al, 1998;Wong et al, 1993). Effects on any of these populations could contribute to the antiproliferative and anti-inflammatory effects of Cyclosporin A.…”

Interleukin-11 Up-Regulates Survivin Expression in Endothelial Cells through a Signal Transducer and Activator of Transcription-3 Pathway

“…To further establish whether IL-11 could increase survivin protein in vivo, we used a human skin xenograft model developed in severe combined immunodeficient (SCID)/beige mice (Murray et al, 1998). Immunostaining of human skin grafts with survivin Ab demonstrated that intradermal injection of IL-11 into human skin grafts increased survivin protein expression in these grafts (Fig.…”

“…Human skin was transplanted to SCID/beige mice as previously described under a protocol approved by Yale Animal Care and Use Committee (Murray et al, 1998). In brief, superficial portions of the skin were harvested in 0.5-mmthick sheets using a Goulian dermatome knife, gauge size, 0.016 (Weck, Research Triangle Park, North Carolina), and cut into approximately 1 cm 2 pieces, which were kept in RPMI 1640 (Life Technologies) at 4°C until transplantation (not longer than 6 hours).…”

Human allograft rejection in humanized mice: a historical perspective

“…In an effort to improve human cell engraftment and function in immunodeficient mice, Pober and colleagues initiated a series of studies using CB17-scid mice co-expressing the beige (Lyst bg ) mutation (SCID/beige). [59][60][61] The beige mutation disrupts a gene required for lysosomal trafficiking and results in impaired NK cell function. 62,63 The use of SCID/beige mice allowed engraftment of human PBMC without depletion of NK cells, but still required the injection of high numbers of cells (1310 8 -3310 8 cells).…”

“…64 Injection of human PBMC or T-cell lines into SCID/beige mice bearing human skin allografts produced allograft injury that was characterized by vascular damage, and this injury was mediated by human CD4 and CD8 T cells. [59][60][61] The SCID/beige model has since proven useful in characterizing allograft injury mediated by human T cells. Inhibition of human T-cell function by treatment of skin allograft bearing SCID/ beige mice with a combination of cyclosporine and rapamycin significantly reduced the level of human cell infiltrate and microvascular damage.…”