title: Allogenicity of cryopreserved human fibroblasts: cryopreservation does not downregulate the allogenicity of fibroblasts making up the matrices of allografts.
abstract: BACKGROUND
  Although cryopreserved tissue allografts are being widely used, long-term degeneration of implanted cryopreserved allografts has become a problem. Although immunologic rejection has been suggested to play a part in this degeneration, cryopreserved allografts are considered to be less immunogenic than fresh allografts.
  
  
  OBJECTIVE
  We investigated the effect of cryopreservation on the allogenicity of the fibroblasts that make up the matrices of allografts.
  
  
  METHODS
  Fibroblast cell strains obtained from surgically resected lung specimens were used. Allogenicity-related antigens expressed on the cell surface (human leukocyte antigen 1, human leukocyte antigen 2, and intercellular adhesion molecule 1), stimulation indices during 1-way mixed lymphocyte-fibroblast cell culture, and proliferation indices of freshly passaged fibroblasts and cryopreserved fibroblasts stored for 1, 4, and 24 weeks were examined. Flow cytometric analysis with monoclonal antibodies was used to test for cell surface antigens, and a colorimetric methyl-thiazol-diphenyl-tetrazolium assay was used to assess stimulation indices and fibroblast proliferation indices. The effect of exogenous interferon-gamma on the degree of expression of human leukocyte antigen 1, human leukocyte antigen 2, and intercellular adhesion molecule 1 was examined simultaneously.
  
  
  RESULTS
  The proliferation indices of fibroblasts were well maintained by cryopreservation. Expression of human leukocyte antigen 1, human leukocyte antigen 2, and intercellular adhesion molecule 1 by fibroblasts was significantly upregulated by interferon-gamma, and cryopreservation did not downregulate this expression.
  
  
  CONCLUSIONS
  Our study suggests that although the fibroblast cell component may be beneficial in restoring allograft function properties initially, it may render the implanted allograft more immunogenic, ultimately resulting in greater rejection and inflammatory responses by the host and, in turn, degeneration of the graft.
authors.affiliation: Department of Cardiothoracic Surgery, Faculty of Medicine, University of Tokyo, Tokyo, Japan. MURAKAWA_THO@h.u-tokyo.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Murakawa
authors.forename: J
authors.initials: J
authors.lastname: Nakajima
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.forename: A
authors.initials: A
authors.lastname: Murakami
authors.forename: Y
authors.initials: Y
authors.lastname: Suematsu
authors.forename: S
authors.initials: S
authors.lastname: Takamoto
mesh_terms: D000704:Analysis of Variance; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000378:metabolism*; D018929:Cell Culture Techniques; D003124:Colorimetry; D015925:Cryopreservation; D005347:Fibroblasts / Q000276:immunology* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D008168:Lung / Q000166:cytology; D014184:Transplantation, Homologous; D015854:Up-Regulation
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D007371:Interferon-gamma