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Biomedical subjects

S Pestka

Publications and source records attributed to S Pestka.

At least 217 records · Page 12Linked to original sources
PubMed1980

Human leukocyte interferon produced by E. coli is biologically active.

A human leukocyte interferon cDNA was enzymatically synthesized, inserted into the vector pBR322, and cloned in Escherichia coli. The DNA sequence codes for a 23-amino acid signal peptide followed by an interferon polypeptide of 165 amino acids. An expression plasmid was constructed which permits the synthesis in E. coli of 2.5 x 10(8) units of interferon per litre of culture. This LeIF protected squirrel monkeys from lethal encephalomyocarditis virus infection.

Amino Acid Sequence↗
PubMed1980

Synthesis of human fibroblast interferon by E. coli.

A cDNA library was constructed using mRNA from human fibroblasts induced with poly(I):poly(C). A bacterial clone containing fibroblast interferon cDNA sequences was identified by hybridization to a cDNA probe synthesized using deoxyoligonucleotide primers which hybridize to fibroblast interferon mRNA specifically. Expression plasmids were constructed which permitted the synthesis in E. coli of 8 x 10(7) units of human fibroblast interferon per liter of culture. The bacterially produced fibroblast interferon is indistinguishable from authentic human fibroblast interferon by several criteria.

Amino Acid Sequence↗
PubMed1980

NH2-terminal amino acid sequence of human fibroblast interferon.

The purification of human fibroblast interferon by chromatography on Blue Sepharose and high-performance liquid chromatography is described. The amino acid composition and a partial sequence of the homogeneous protein are reported. The NH2 terminus was determined to be NH2-Met1-Ser-Tyr-Asn-Leu-Leu-Gly-Phe-Leu-Gln-Arg-Ser-Ser-Asn-Phe-Gln-X-Gln-Lys.

Amino Acid Sequence↗
PubMed1980

Construction and identification of bacterial plasmids containing nucleotide sequence for human leukocyte interferon.

Bacterial plasmids containing human leukocyte interferon sequences were constructed and identified. Identification was confirmed by correspondence of the nucleotide sequence with out amino acid sequence of human leukocyte interferon. The finding of bacterial recombinants containing distinct leukocyte interferon sequences is consistent with our purification of different leukocyte interferon species. We conclude that what has been designated human leukocyte interferon is, indeed, a class of homologous proteins. Preliminary indications suggest that their diversity appears to be represented by individual genomic equivalents. Each of the individual species exhibits characteristic activities. The structural modulation of these biological activities has immense significance for understanding the natural role of the interferons and for refining and developing their ultimate therapeutic potential.

Base Sequence↗
PubMed1980

Amino-terminal amino acid sequence of human leukocyte interferon.

We report the amino-terminal sequence of the first 22 amino acids of human leukocyte interferon. These and other results indicate that human leukocyte interferon consists of many individual species. We, therefore, postulate that diversity in this protein is routinely present and that the human leukocyte interferons represent a multigene family.

Amino Acid Sequence↗
PubMed1980

Augmentation of human K-cell activity with interferon.

Our laboratory recently reported that interferon (IF) could augment human antibody-dependent cellular cytotoxicity (ADCC) and cytotoxicity by natural killer (NK) cells. Although there is general agreement that IF can boost the activity of human NK cells, two laboratories have reported a failure to boost ADCC. We have therefore examined in more detail the effects of IF on human ADCC. We have found, by several lines of evidence, that IF can indeed appreciably augment the activity of K cells, the subpopulation of lymphocytes that mediate ADCC: (1) human leucocyte IF, purified to homogeneity, boosted ADCC: (2) IF augmented ADCC against target cells that were completely resistant to NK activity; and (3) the ADCC activity of leukaemic cells from a patient with chronic lymphocytic leukaemia (CLL) which lacked any detectable NK activity was boosted by IF. These results are consistent with the hypothesis that human NK and K cells are the same subpopulation of lymphocytes and that the mechanisms regulating their activity are similar. However, the absence of NK activity in the CLL patient strongly supports the idea that not all FcR-positive cells are NK and that ADCC effectors devoid of NK may exist. However, further evidence is required to analyse this point.

Animals↗
PubMed1980

Leukocyte interferon-induced tumor regression in human metastatic breast cancer, multiple myeloma, and malignant lymphoma.

Thirty-eight patients with advanced breast cancer, multiple myeloma, and malignant lymphoma were treated with partially purified (about 0.1%) leukocyte interferon. Patients were treated with a remission-induction schedule of 3 million to 9 million antiviral units daily intramuscularly for 4 to 26 weeks. Responding patients were maintained on a schedule of 3 million U three times weekly. Tumor regression was observed in seven of 17 patients with breast cancer. Six of 10 patients with multiple myeloma responded with a decrease of at least 50% in serum myeloma protein levels or Bence Jones protein excretion. Six of the 11 lymphoma patients achieved tumor regression. Complete remissions occurred in two patients. Of the 19 responding patients, five remain on study for 52 to 63 weeks. Toxicity included low-grade fever, fatigue, anorexia, and partial alopecia. Myelosuppression (lowest median leukocyte count, 2500/mm3; granulocytes, 1300/mm3) occurred in most patients. On the basis of this pilot study, we conclude that leukocyte interferon can induce tumor regression in patients with advanced cancer.

Adult↗
PubMed1979

Precursor sequence of MOPC-315 mouse immunoglobulin heavy and light chains.

Partially purified mRNA coding for the MOPC-315 heavy (alpha) or light (lambda 2) immunoglobulin chain was translated in a nuclease-treated reticulocyte lysate containing 20 labeled amino acids. Radiolabeled precursor heavy and light chains, purified by immunoprecipitation and preparative gel electrophoresis, were subjected to Edman degradation. The labeled phenylthiohydantoin derivatives obtained in each degradative cycle were identified and quantitated by high pressure liquid chromatography. Both heavy and light chain precursor segments were hydrophobic in nature; however, they were not homolgous in sequence. To establish whether COOH-terminal proteolytic processing of the heavy chain might also be occurring during secretion, the cyanogen bromide peptides of the heavy chain precursor were compared to those of the mature secreted heavy chain. The results indicated that the COOH termini of the two chains were identical.

Amino Acid Sequence↗
PubMed1979

Ribosomal protein alterations in thiostrepton- and Micrococcin-resistant mutants of Bacillus subtilis.

Ribosomal proteins of parental thiostrepton- and micrococcin-sensitive Bacillus subtilis cysA14 and thiostrepton-and micrococcin-resistant mutants were compared. Several electrophoretic and immunochemical techniques showed unambiguously that BS-L11 was not present on 50 S ribosomal subunits from the six thiostrepton-resistant mutants. Protein BS-L11 reappeared in all six revertants from thiostrepton resistance to thiostrepton sensitivity. No definitive protein alteration could be ascribed to the mutation from micrococcin sensitivity to resistance. It was also demonstrated that B. subtilis protein BS-L11 is homologous to Escherichia coli ribosomal protein L11. The finding that ribosomes from thiostrepton-resistant mutants do not contain protein L11 suggests that L11 not only is involved in binding of thiostrepton, but also, when mutationally altered, confers resistance to this antibiotic. Although the ribosomes of these strains do not contain protein L11, all thiostrepton-resistant mutants showed the same viability as the parental strain. Thus protein L11 cannot be obligatory for the structure and function of the ribosome.

Anti-Bacterial Agents↗
PubMed1979

Human leukocyte interferon: production, purification to homogeneity, and initial characterization.

A method of fractionating proteins by high-performance liquid partition chromatography has been developed and used for isolation and purification to homogeneity of one of the species of human leukocyte interferon. The homogeneous interferon exhibited a sharp peak on high-performance liquid chromatography and a single narrow band on sodium dodecyl sulfate/polyacrylamide gel electrophoresis in the presence of 2-mercaptoethanol. Extraction of the gel gave a single sharp peak of antiviral activity coinciding with the protein band. The specific activity of pure interferon was found to be 2--4 X 10(8) units/mg, based on amino acid analysis. The molecular weight is 17,500--18,000.

Amino Acids↗
PubMed1978

Human leukocyte interferon purified to homogeneity.

One of the species of human interferon produced by incubation of leukocytes with Newcastle disease virus was purified to homogeneity. It exhibited one peak of activity coinciding with a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Humans↗
PubMed1978

Thiostrepton-resistant mutants exhibit relaxed synthesis of RNA.

Spontaneous mutants of Bacillus subtilis resistant to thiostrepton (TSP) exhibit relaxed synthesis of RNA when starved for required amino acids. Intact cells of tsp mutants cannot synthesize the regulatory nucleotides, ppGpp and pppGpp, after amino acid deprivation. Because ribosomes isolated from spontaneous revertants to thiostrepton sensitivity and from wild-type stringent strains can synthesize (p)ppGpp whereas ribosomes isolated from tsp strains cannot synthesize these regulatory nucleotides in the presence of stringent factor, it appears that the lesion is expressed at the level of the ribosome. Genetic mapping, via three-factor transformational crosses, has shown that tsp is closely linked to rif, in the order cysA14, tsp, rif-I, strA. The phenotype of the tsp mutants indicates that they are of the relC type. Their map position indicates that they are different from a previously described B subtilis rel mutation. Ribosomes from the latter strain can synthesize (p)ppGpp in cell-free extracts.

Amino Acids↗