SUMMARYHuman leukocyte interferon (HuLeIF) preparations were separated into populations of molecules with different sizes, by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), and with different charges, by isoelectric focusing. These populations with different sizes and charges were analysed for their antiviral activity on homologous cells and on heterologous (bovine) cells.The distribution of interferon activity into two broad peaks by SDS-PAGE was similar whether assayed on human or bovine cells. However, within these peaks, the relative ratio of the activity in human cells and bovine cells varied significantly: while most of the size components had similar human/bovine cell activities, the fastest migrating component (apparent tool. wt. ~ ~35oo) was more than IOO times more active on bovine cells than on human cells.The peaks of activity in isoelectric focusing were distributed from pH 5"5 to 7"o. There was generally correspondence between human and bovine cell activities, but while the more neutral pH range peaks were consistently slightly more active on human cells than on bovine cells, the more acid range peaks were always slightly more active on bovine cells than on human cells. However, with the most acidic peak, there was more than Ioo times greater activity on bovine cells than on human cells.These data show that the heterogeneity of HuLeIFs is greater than merely two size populations, and data confirm that different forms of human leukocyte interferon can vary markedly in biological activity.
Mouse interferons appear as two distinct molecular forms, one migrating at 38,000 daltons in sodium dodecyl sulfate/polyacrylamide gels and one migrating at 22,000 daltons; these interferons comprise about 80% and 20% of total activities, respectively. When such interferon preparations are briefly exposed to acidic periodate buffer, the larger interferon species is apparently converted to the smaller form since the activity at 38,000 daltons is completely eliminated while the activity at 22,000 daltons increases significantly; upon further oxidative cleavage, antiviral activity becomes detectable migrating at 15,000 daltons. Because no native mouse interferon has been reported as such small molecules, this antiviral activity is designated mouse "interferoid" to distinguish it from the native, naturally occurring interferon forms. Prolonged acidperiodate treatment fails to quantitatively convert the 22,000-dalton interferon to the 15,000-dalton interferoid since both are inactivated. When L cells are induced to make interferon in the presence of glycosylation inhibitors, either D-glucosamine or 2-deoxy-Dglucose, they produce approximately normal levels of antiviral activity. However, when such preparations are analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, little activity (<10%) migrates as either the 38,000-dalton or 22,000-dalton native interferons. The interferons and interferoid are antigenically and hydrophobically indistinguishable. These data suggest that induced mouse cells normally synthesize the interferoid as a precursor pol ieptide that is either partially or extensively modified by carbohydrate additions to produce, respectively, the 22,000-and 38,000 dalton mouse interferons. Because interferoid is apparently fully biologically active without these moieties, chemical synthesis of such unmodified polypeptides or active fragments from them appears feasible.Mouse interferon preparations migrate as two distinct molecular-size species in sodium dodecyl sulfate (NaDodSO4)/ polyacrylamide gel electrophoresis, at 38,000 daltons and 22,000 daltons, comprising about 80% and 20% of the total activity, respectively (1). These data clearly demonstrate that the larger mouse interferon is not a dimer of the smaller form, as has been claimed (2); support for these data has been provided by others (3-6). The two mouse interferon species also differ in crossspecies antiviral activity (7) and in effects of reducing agents (1,7,8). However, their ratios of antiviral and cell-multiplication-inhibitory activities were found to be identical (5,8), and both bands of activity appeared to be glycoproteins since they stained with both Coomassie brilliant blue and periodic-acidSchiff stain (5, 6). It has been suggested that either these interferons differ on the basis of extent of carbohydrate additions to a common active core polypeptide or they are different gene products (1, 5, 7). In the present studies, we undertook to resolve which of these possibilities is correct.Efforts are presently un...
The early diagnosis of human rotavirus infection is essential for effective patient management and infection control. We report here a rapid, easy-to-perform, and inexpensive test for rotavirus detection. The viral RNA is extracted directly from the stools and electrophoresed on 1% agarose gels. Currently available immunoassays for routine diagnostic purposes are directed at the common group A-specific antigen. As reports become available on human gastroenteritis caused by the atypical or novel rotaviruses, this technique presents an added advantage in that it can detect both group A and non-group A rotaviruses.
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