Scanning Microscopy


Human alpha interferons (IFN-a) cause a reorganization of internal cell membranes into tubuloreticular inclusions (TRI). Morphogenesis and cytochemistry indicate a pre-Golgi intracisternal origin from the endoplasmic reticulum. Clinically, TRI formation in human blood mononuclear cells correlates with systemic IFN-a treatment or with endogenous overproduction of IFN-a in viral or autoimmune diseases (e.g., rubella syndrome, AIDS, systemic lupus erythematosus). In vitro, TRI formation can be produced by treatment of Daudi lymphoblasts or vascular endothelial cells with IFN-a, and is blocked by actinomycin-D. In Daudi lymphoblasts or vascular endothelial cell cultures, TRI formation parallels induction of 2'-5' A synthetase, inhibition of thymidine kinase and growth inhibition; however, heavy water treatment of Daudi cells prevented TRI formation while induction of 2'-5' A synthetase and growth inhibition persisted. TRI formation was dissociated from IFN-a antiproliferative activity in a mutant clone of Daudi lymphoblasts. Decreased glycoprotein biosynthesis and increased phospholipid biosynthesis may accompany progressive TRI accumulation.

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