Immunologic properties of human dermal fibroblasts

Human dermal fibroblasts are known not to express human leukocyte antigen (HLA)-DR message or protein in the absence of interferon (IFN)-γ. To use allogeneic dermal fibroblasts for cell therapy, as a revalidation, the cells at passage 12 were analyzed for HLA-DR mRNA and surface protein. Although no significant HLA-DR surface protein was found, HLA-DR mRNA expression was observed, without interferon-γ. At an early passage, although HLA-DR surface protein was not found, prominent expression of HLA-DR mRNA was observed without IFN-γ stimulation, which was not typical of dermal fibroblasts studied so far. Intracytoplasmic HLA-DR protein was also not detected, which suggests that the mRNA was not translated. There was no marked stimulation of T-cell proliferation by the fibroblasts in the absence or presence of IFN-γ. Interestingly, indoleamine dioxygenase, a molecule involved in immunosuppression, was also expressed in dermal fibroblasts in the absence of IFN-γ.