Immunofluorescent visualization of myosin in human epidermal cells

Immunohistochemistry in cutaneous pathology

Since the first demonstration of skin antibodies in sera of pemphigus patients by IF (Beutner & Jordon 1964), the scope of skin diseases in which immunologic findings may be of interest has enormously enlarged and dermatology remains one of the leading clinical specialities applying IHC in both diagnosis and research. Immunohistological techniques and, to a lesser degree, immunocytological techniques, have been developed to include not only IF, but also immunoenzymatic methods. Even if not all immunological findings may be disease specific and diagnostic, immunohistological techniques have become a very useful tool for studying skin biopsies in connection with serological methods. Their importance could be increased with rapid development of a new field: the study of normal skin constituents; e.g. Ag, collagen, keratin, with the help of specific polyclonal and monoclonal antibodies.

Mallory bodies: lesions of hepatocytes containing proteins of the keratin-myosin-epidermin group

Mallory's alcoholic hyalin in hepatocytes was found also in other diseases and is now referred to as Mallory bodies. Data concerning their histochemical, immuno and electron microscopic properties are partly contradictory. In this study, early stages of Mallory bodies reacted strongly with configurational technics for myosins; affinity tended to decrease when material with the properties of keratohyalin and the matrix of stratum corneum was formed. Thus, many Mallory bodies contained histochemically distinct myoid and keratin-like proteins. Electron microscopists demonstrated thick and thin filaments resembling contractile systems in Mallory bodies; the failure of immunologists to visualize actomyosin may be due to the heterogeneity of these proteins. The currently popular term prekeratin has been applied to a variety of substances extracted from epidermis, hoof and hair under different conditions. The prekeratin of recent immunofluorescence studies seems to contain mainly epidermin and low molecular matrix proteins; both were studied extensively by chemists. Epithelial filaments, including tonofibrils and contractile fibrils regarded as a subgroup of myofibrils, were well known half a century ago, but were banished by electron microscopy. Observations in this study and data on epidermal actomyosin indicate that different proteins of the k-m-e-f group can indeed coexist in epithelial cells. The formation and resolution of Mallory bodies can be regarded as an example of the well known shifts of epithelial cells between secretory and keratinizing states.