[Isolation and properties of monomeric and oligomeric forms of gene-engineered human leukocyte interferon alphaA from Pseudomonas sp].

Using stepwise ion-exchange and gel-permeation high performance liquid chromatography and SDS-PAAG gel electrophoresis, it was demonstrated that the non-reduced gene-engineered interferon alpha A is represented by multiple forms, namely, four monomers, four dimers, two trimers and one tetramer. All the protein forms were obtained in an individual state and characterized in terms of antiviral activity and immunochemical properties. The heterogeneity of the protein is due both to the formation of anomalous intermolecular disulfide bonds and to the existence of reduced S-S bonds. The antiviral activity of the dimers, trimers and tetramers expressed as units per mole of protein is equal to that for the monomeric form, i.e., the interaction of one monomeric subunit of the covalently-linked oligomer is sufficient for the manifestation of the protein antiviral activity. This suggests that the antiviral status of the cell does not depend on the amount internalized interferon molecules of their processing products but is controlled by the cell receptor whose internalization and, possibly, processing stimulate the transcription of genes involved in the triggering of the immune response.