Objective: The immunogenicity of tissue engineered skins is still vague, though it has been applied clinically for several years. To observe the evidence of immunologic rejection of tissue engineered skins transplanted to severe combined immunodeficiency (SCID) mice, which are implanted human splenic lymphocytes to construct human immune system.
Methods: Tissue engineered skins and acellular dermic matrix were constructed in vitro. Twenty SCID mice, aging 4-6 weeks and weighing 16-17 g, were randomly divided into four groups equally (n=5). The tissue engineered skins, human foreskins from circumcision and acellular dermic matrix were transplanted to groups A, B, and C, respectively; group D was used as a control. After 2 weeks of transplanting, 3 x 10(7) human splenic lymphocytes were injected into every SCID mouse intraperitoneally. After 4 weeks, the morphology, histology, immunohistochemistry and human IgG immunofluorescence were used to observe immunologic rejection.
Results: Group A showed that transplanted tissue engineered skins had the bilayer structure of dermis and epidermis, which was similar to the normal human skin structure. Group B showed that the transplanted human foreskins still retained normal structure of human skin. Group C showed that acellular dermic matrix were located in situ and had no sign of degradation. After injecting human splenic lymphocytes into the SCID mice, no inflammatory cells infiltration were observed basically in groups A, C, and D; the inflammatory cells infiltration of group B were significantly higher than that of other 3 groups (P < 0.05). The results of anti human keratin 14 monoclonal antibody (mAb) staining and anti human type IV collagen mAb staining were positive in group A; no positive cells for CD3, CD4, and CD8 were observed in groups A, C, and D; and many positive cells for CD3, CD4, and CD8 were observed in group B. The results of IgG immunofluorescence staining was negative in group A, C, and D, and positive in the great vessel wells of group B.
Conclusion: The immunogenicity of tissue engineered skins is very weak, and tissue engineered skins would not be rejected by host immune system after transplantation.