Peter Swetly

A novel class of human type I interferons

The screening of a cDNA library prepared from mRNA of Sendai virus induced Namalwa (human Burkitts lymphoma) cells, using a human IFN-alpha 2 DNA probe under conditions of low stringency, identified two weakly hybridizing clones containing sequences related to, but discernably different from those of the IFN-alpha class. Sequence and hybridization analysis of these cDNAs as well as expression in E. coli provided evidence that they encode proteins which have the characteristics of IFN type I but which are sufficiently diverged in sequence from both IFN-alpha s and IFN-beta to suggest that they are representatives of a new and distinct class of interferons named interferon-omega. Hybridization of these sequences to genomic DNA reveals that this class contains at least four members.

Construction of expression plasmids producing high levels of human leukocyte-type interferon in Escherichia coli

An expression plasmid was constructed, consisting of the promoter/operator region of the tryptophan operon from Serratia marcescens and a synthetic ribosome-binding site ligated into pBR322. Leukocyte-type interferon gene fragments (IFN-alpha A and IFN-alpha C) isolated from a cDNA library from human lymphoblastoid (Namalwa) cells were inserted into the unique HindIII site of the expression plasmid, and the resulting recombinant plasmids directed the synthesis of up to 5 X 10(5) units of A-type preinterferon, 2 X 10(7) units of A-type mature interferon and 8 X 10(5) units of C-type mature interferon per liter culture.

Monoclonal antibodies to yeast catalase T

Abstract Hybridoma cell lines secreting antibodies directed against Saccharomyces cerevisiae catalase T were constructed by fusing spleen cells of mice immunized with catalase T with P3×63Ag8 mouse myeloma cells. Culture supernatants were assayed for specific antibodies by incubation with 35S-labelled yeast extracts, adsorption of the immune complexes to Protein A — carrying Staphylococus aureus cells and analysis of the adsorbed yeast proteins by sodium dodecylsulfate gel electrophoresis. Two hybrid clones were isolated mediating adsorption of a protein with electrophoretic mobility of catalase T; one of them, showing considerably higher activity, was characterized further. Anti-bodies produced by this clone belong to the IgG class of immuniglobulins; they can be used for immunoadsorption, but not for direct immunoprecipitation and recognize authentic catalase T as well as catalase T apoprotein.

Effects of butyrate on induction and action of interferon

Abstract We have identified two different and independent effects of sodium butyrate on induction and action of interferon. In the monkey cell line, GL-V3, simultaneous treatment with interferon and butyrate strongly reduced the antiviral activity of the interferon preparation, Whereas addition of butyrate before interferon or after establishment of the antiviral state had no effect. Interferon production induced by Sendai virus was also reduced by simultaneous treatment with butyrate, but pretreatment resulted in marked enhancement of interferon yields. Whereas the inhibitory effects of simultaneous butyrate treatment were also observed in human (WISH) and bovine (MDBK) cells, pretreatment with butyrate in these cells had no effect on interferon yields.

The human lymphoma cell line NC-37: An alternative source of human lymphoblastoid interferon

Abstract NC-37 lymphoma cells treated with n-butyrate or 5-bromodeoxyuridine (BrdUrd) and induced with Sendai virus produced crude interferon with titers of up to 2 × 105 units/ml (100 units/103 cells) and with specific activities of up to 106 units/mg protein. More than 90% of the interferon activity was neutralized by antiserum against human interferon type α (HuIFN-α). Treatment of the cells with BrdUrd, but not with butyrate, resulted in the production of moderate amounts of interferon without virus induction.