Construction of three-dimensional gel of extracellular matrices including type VI collagen and its role for immune reaction

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Epidermal Langerhans cells are now recognized as designed to present antigenic signals to Tlymphocytes and trigger an immunologic response. The cells also exist in the stratified squamous mucosal epithelium of mouse forestomach and tongue. Langerhans cells reside in the epidermis, and migrate into dermis, finally to the draining lymph nodes, where they present antigenic signals to T lymphocytes. For the search of interaction between extracellular matrices and immune cells, it is useful to study migration pathway of Langerhans cells in the dermis.Among many extracellular matrices, type VI collagen is a macromolecular component of extracellular matrices. They were widely distributed in connective tissues. Electron microscopic examinations and analysis of the amino acid sequences revealed that type VI collagen may work as an anchor in cell-matrix or matrix-matrix interaction.We investigated the effect of fibril-forming collagens or other extracellular matrices on the adhesion of macrophages. Adhesion of macrophages to plastic or fibronectin was associated with the induction of tyrosine phosphorylation. In contrast, the induction of protein tryosine phosphorylation was markedly inhibited on type I collagen. Type I collagen is a non-adhesive extracellular matrix causing cell migration on immuno reactions.The surface structure of D-periodic striated collagen fibrils of mouse tail tendon was examined by atomic force microscopy (AFM). Native collagen fibrils were spread on the cover glass and observed with AFM without any treatment. The band depth was estimated. A quantitative evaluation of collagen structural features in the nanometer scale is made possible by AFM.This microscopy is also useful to study three-dimensional structure of the gel composed of extracellular matrices.