IMMUNOLOCALIZATION OF TGF-BETA(1) IN HUMAN HYPERTROPHIC SCAR AND NORMAL DERMAL TISSUES

Following severe thermal injury and other injuries to the deep dermis of the skin, patients frequently develop hypertrophic scarring (HSc) which is characterized by an over-abundance of extracellular matrix (ECM) proteins including collagen, Our previous work revealed a synchronous elevation in expression of mRNA for transforming growth factor (TGF)-beta(1), type I and type III procollagen in human HSc tissue, suggesting a possible role of locally synthesized TGF-beta(1) in matrix production, In this study the immunoreactive sites of TGF-beta(1) protein in hypertrophic and normal dermal (ND) tissue obtained from the same patients have been determined by an immunoperoxidase staining system, We used two TGF-beta(1)-specific rabbit polyclonal antibodies known as anti-LC and anti-CC which were prepared to different synthetic preparations of a peptide corresponding to the first 1-30 amino acids of the amino-terminus of mature TGF-beta(1). These antibodies have affinity for two distinct epitopes of TGF-beta(1). The anti-LC antibody localized TGF-beta(1) to non-proliferating/differentiated epidermal cells, suprabasal keratinocytes in both normal and HSc tissues, The intensity of this staining was significantly higher (150 +/- 26 sq, micron vs 77 +/- 7 sq, micron, n = 5, P < 0.05) in normal tissues compared to HSc tissues, When the anti-CC antibody was used as the primary antibody, intense staining of focal regions was observed in the dermis of HSc tissue, but not in ND tissue obtained from the same patient, These foci contained collagen which was nodular, distributed in whorl-like arrangements and highly enriched with microvessels. Expression of anti-CC reactive TGF-beta(1) in the nodular structures of HSc suggests that this cytokine is involved in the development of the collagenous nodules characteristic of this fibrotic condition, Further, the low intensity of anti-LC reactive TGF-beta(1) in the epidermis of HSc tissue suggests that suprabasal keratinocytes in this tissue are proliferating/undifferentiated.