Theophil Staehelin

High frequencies of antigen-specific hybridomas: dependence on immunization parameters and prediction by spleen cell analysis.

Hybridomas producing antibodies against soluble antigens have in most cases been difficult to establish. After fusion of myeloma cells with spleen cells obtained from mice immunized with a soluble protein, hybridomas secreting specific antibodies have been observed to occur very rarely among non-specific hybridomas. We found that the frequency of specific hybridomas correlates directly with the increase over background of the frequency of blast and/or plasma cells in the spleen (measured by cell size analysis) after antigenic stimulation. High yields of specific hybridomas were obtained simply by following a novel immunization technique consisting of several conventional preimmunization courses followed by 4 very high doses of antigen in saline on each of the last 4 days before fusion.

Monoclonal antibodies can discriminate between some active and inactive forms of leukocyte interferon

Antiviral activity of recombinant human leukocyte A interferon was inactivated by heating at 65 degrees C or by reduction of disulfide bonds. The specific immunoreactivity, as measured by radioimmunoassays measuring binding to monoclonal antibodies, decreased concomitantly with the antiviral activity. Although the monoclonal antibodies did bind to inactivated interferon, their binding affinity to inactivated interferon was in general very much lower than their binding affinity to active interferon. Therefore, this immunoassay could replace the antiviral assay for detection of biologically active interferon. In addition, most of these antibodies should be especially useful for purification of the interferons since they discriminate between the native active and inactive denatured species. Screening for such antibodies is convenient and simple. The general use of antibodies that preferentially interact with native molecules provides a powerful new principle for choosing monoclonal antibodies with extraordinary potential in assay and purification.

Base-pair formation between 18 S ribosomal RNA and globin mRNA during initiation of protein synthesis in vitro

A stable complex between 18 S rRNA and globin mRNA has been isolated from 40 S initiation complexes in the reconstituted reticulocyte cell free system. This complex is only formed under the conditions which also lead to an initiation complex active in protein synthesis. The mRNA—18 S rRNA interactions has properties compatible with base‐pairing. This observation is discussed in the context with other, in part controversial, observations relating to base pairing as a step in initiation of eukaryotic protein synthesis.

In vitro synthesis of biologically active human leukocyte interferon directed by recombinant plasmid DNA.

Abstract Recombinant plasmid DNA containing a human leukocyte interferon coding sequence was used as template in an Escherichia coli DNA-dependent cell-free system. Biologically active leukocyte interferon was synthesized.

Chapter 21. The Human Interferons

Publisher Summary The interferons are proteins with characteristic antiviral activities and species specificities produced by various cells. Even within species, several interferons are produced with biologically, chemically, and physically distinct antiviral activities. In general, the species specificity of an interferon provides a characteristic profile of each interferon. For example, human leukocyte interferon exhibits a high degree of antiviral activity in bovine or porcine cell cultures, whereas fibroblast interferon is hardly active and immune interferon shows no activity on these cells. The human interferons have been classified into three distinct classes by their antigenic, biological, and chemical properties. These are human leukocyte (L), fibroblast (F), and immune (I) interferons (IF). These are species that are predominantly synthesized by buffy coat leukocytes (IFL), fibroblasts (IFF), and T-lymphocytes (IFI). Preliminary clinical trials have indicated that human interferon is effective in a number of viral diseases. Studies have suggested that interferon may have anti-tumor effects on several human malignancies. Additional clinical evaluations are in progress, but because of the difficulty of obtaining large amounts of human interferon, clinical trials have been limited. Monoclonal antibodies have proven to be invaluable for characterization, quantitative analysis, and purification of macromolecular antigens. Of particular interest and value are antibodies against biologic allyactive compounds, such as interferon. Until recently, quantitation of interferon could only be determined by relatively complex and time-consuming assays.

Monoclonal Antibodies Against two Antigens of Clinical Interest

Abstract With six monoclonal antibodies (mAb) against β-thromboglobulin (βTG) and with over 20 mAb against prostatic acid phosphatase (PAP) sandwich assays for these clinically important proteins were developed. The analysis of the epitope specificities, development of the assays as well as some preliminary clinical results (with the PAP-assay) are described.

Monoclonal Antibodies to the Human Leukocyte Interferons and their Use for Interferon Purification and a Quantitative Interferon Assay

Abstract Thirteen monoclonal antibodies to human leukocyte interferon have been obtained. They exhibit different patterns of binding to purified leukocyte interferon species that are consistent with the structural multiplicity of the human leukocyte interferons. These antibodies are useful as probes into the structure of the human leukocyte interferons and for their purification by affinity chromatography. A simple and highly sensitive assay for leukocyte interferon was developed with the use of two monoclonal antibodies.