Mouse monoclonal antibody with specificity for human interferon gamma

Monoclonal antibody to human beta interferon: characterization and application

Seven stable mouse hybridomas secreting monoclonal antibodies to human fibroblast beta interferon (IFN-beta) were isolated, all seven of which belonged to IgGl subclass and kappa type. While neutralizing the antiviral activity of human fibroblast IFN-beta, they failed to neutralized both that of human IFN-alpha and human IFN-gamma. These monoclonal antibodies neutralized the antiviral activity of human fibroblast IFN-beta but not that of human IFN-alpha and IFN-gamma. Two of the seven monoclonal antibodies, YSB-1 and YSB-2, showed particularly high neutralization titers in the ascitic fluid. Monoclonal antibodies were purified from cultures of hybridoma grown in a serum-free medium. The purified monoclonal antibodies, YSB-1(5 micrograms/ml) and YSB-2(1 microgram/ml), neutralized IFN-beta from 10EU/ml to 1EU/ml. Human fibroblast IFN-beta was purified to 3.5 X 10(7) IU/mg protein (1.0 X 10(8) IU/mg protein in the peak fraction) by the monoclonal antibody (YSB-2) affinity column chromatography, whereas human recombinant IFN-beta obtained from E.coli was also purified to 6.5 X 10(7) IU/mg protein (1.1 X 10(8) IU/mg protein in the peak fraction) by the monoclonal antibody (YSB-1) affinity column chromatography.

Monoclonal antibodies to human interferon-gamma. II: Antibodies with neutralizing activity

Two types of hybridomas secreting monoclonal antibodies (MAB) with neutralizing activity against human interferon-r (HuIFN-r) were obtained by somatic cell hybridization between mouse myeloma P3UI cells and spleen cells from BALB/c mice immunized with purified recombinant HuIFN-r and a conjugate of a synthetic amino-terminal peptide (residues 4-21) of HuIFN-r and bovine thyroglobulin. One of these MAB recognized the amino-terminal region (residues 4-21) of HuIFN-r, and the other recognized some region in the internal part (residues 22-130) of the molecule. These results suggest that another region, in addition to the amino-terminal region, contributed to the biological activity of rHuIFN-r. A combination of one of these MAB and a previously described MAB directed to the carboxyl-terminal region (residues 131-146) of HuIFN-r enables a quantitative and sensitive assay method of biologically active rHuIFN-r.

Immunomodulation of human leukocytes by staphylococcal enterotoxin A: augmentation of natural killer cells and induction of suppressor cells

Staphylococcal enterotoxin A (SEA), a protein isolated from culture supernatants of Staphylococcus aureus, is a potent T-cell mitogen and an inducer of interferon-gamma (IFN-gamma). We report here that SEA exhibits a number of significant in vitro immunomodulatory functions. In vitro treatment of human peripheral blood monocyte-depleted lymphocytes with SEA resulted in significant augmentation of their natural killer cytotoxicity against target cells from hemopoietic (K562, Daudi) or solid (melanoma, lung, colon) human tumor cell lines. SEA was found to be more effective than interferons-alpha (natural or Escherichia coli-derived) in augmenting natural killer (NK) cytotoxicity of peripheral blood lymphocytes. Studies on the kinetics of the augmentation revealed a significant increase of NK within 3 hr of in vitro treatment with SEA at 37 degrees C. A neutralizing monoclonal antibody specific for human IFN-gamma did not affect the augmentation of natural killer cytotoxicity by SEA, suggesting that SEA augmented natural killer cytotoxicity primarily by a mechanism not involving induction of interferon-gamma. Furthermore, in vitro treatment with SEA resulted in significant augmentation of antibody-dependent cell-mediated cytotoxicity and of natural killer-like cytotoxicity, generated in mixed lymphocyte culture, against the K562 targets. Induction of suppressor cells to proliferative responses of autologous or allogeneic mononuclear cells to phytohemagglutinin (PHA) or to allogeneic cells in mixed lymphocyte culture was observed after in vitro treatment of peripheral blood mononuclear leukocytes with SEA for 24 or 48 hr at 37 degrees C. In addition, the presence of SEA in mixed lymphocyte cultures (MLC) resulted in significant inhibition of the generation of specific T-cell-mediated cytotoxicity in MLC. These results suggest that SEA, which may be involved in S. aureus infections and in treatment with extracorporeal perfusion systems over S. aureus columns, can regulate a number of significant lymphoid functions.

Monoclonal antibodies to bovine somatotropin: immunoadsorbent reagents for mammalian somatotropins

Twenty-nine stable hybridoma cell lines secreting monoclonal antibodies to bovine somatotropin (bST) have been produced and characterized. Five of the monoclonal antibodies bind porcine and human somatotropins as well as bST. One of these antibodies was used as a reagent in immunoadsorbent chromatography of recombinant bST or pituitary bST from cell extracts. Following chromatography, the bST preparations retained activity in a rabbit liver radioreceptor assay and in a radioimmunoassay. The immunoadsorbent reagent bound human and porcine somatotropins as well as bovine.