Several inflammatory diseases, including asthma, arthritis and psoriasis are associated with the production of leukotrienes by neutrophils, mast cells and macrophages. The initial enzymatic step in the formation of leukotrienes is the oxidation of arachidonic acid by 5-lipoxygenase (5-LO) to leukotriene A4. Osteosarcoma cells transfected with 5-LO express active enzyme in broken cell preparations, but no leukotriene metabolites are produced by these cells when stimulated with the calcium ionophore A23187, indicating that an additional component is necessary for cellular 5-LO activity. A new class of indole leukotriene inhibitor has been described that inhibits the formation of cellular leukotrienes but has no direct inhibitory effect on soluble 5-LO activity. We have now used these potent agents to identify and isolate a novel membrane protein of relative molecular mass 18,000 which is necessary for cellular leukotriene synthesis.

A 90-kDa surface glycoprotein was previously isolated and shown to be required for infection by the "major" group of human rhinovirus (IRV) serotypes. In the present work, the amino acid sequence of the receptor protein was obtained from CNBr and tryptic peptides. Using degenerate oligonucleotides predicted from the peptide sequences, we identified four cDNA clones that encode a 3-kilobase mRNA. The clones were ligated, subcloned in a simian virus 40 expression vector, and used to transfect receptor-negative Vero (monkey) cells. Results showed that transfected cells expressed receptor molecules capable of binding HRV and a monoclonal antibody which recognizes the mjor group HRV receptor. The cloned receptor cDNA encoded a protein with a sequence nearly identical to that of the intercellular adhesion molecule 1 (ICAM-1), indicating that the two surface proteins are one and the same. Both proteins have identical mass, carbohydrate composition, and tissue distribution. In addition, major group receptors on HeLa cells could be induced with various cytokines in a manner similar to the ICAM-1 ligand. A similar induction of the HRV "minor" group receptor was not observed.Human rhinoviruses (HRVs) are members of the Picornaviridae and are the major causative agent of the common cold in humans (1). Earlier studies have indicated that HRV serotypes can be divided into "major" (78 serotypes) and "minor" (10 serotypes) groups based on receptor specificity (2,3). An anti-receptor monoclonal antibody (designated antibody 1A6) has been previously isolated which specifically blocks attachment of the major group of HRVs (4). By using this antibody, a 90-kDa glycoprotein was isolated from HeLa cell membranes and shown to be required for attachment of the major group of HRVs to susceptible cells in culture (5). Chimpanzee and human clinical trials testing the efficacy of antibody 1A6 have also demonstrated that this receptor is involved in HRV infection of the nasal cavity in vivo (6, 7). Further biochemical characterization of the purified 90-kDa protein demonstrated that it was an acidic glycoprotein having a pI of4.2 (8). Carbohydrates accounted for 30% ofthe molecular mass of the protein and seven N-glycosylation sites were predicted on the basis of partial digestion with N-Glycanase (8).The intercellular adhesion molecule 1 (ICAM-1) is a cell surface ligand for the lymphocyte function-associated antigen 1 (LFA-1) adhesion receptor (9). ICAM-1 is a singlechain 76-to 114-kDa glycoprotein with a polypeptide core of 55 kDa that can be induced by several cytokines (10). The interaction of ICAM-1 and LFA-1 plays an important role in leukocyte adhesion and in the execution of immunological and inflammatory functions (10).The present study describes the cloning and sequencing of the cDNA that encodes the cell surface receptor required for infection by the major group ofHRVs.t Sequence and protein comparisons show that ICAM-1 is the surface glycoprotein utilized by HRVs during infection. MATERIALS AND METHODSPeptide Sequence....

Pure bovine brain-derived acidic fibroblast growth factor is a very potent mitogen for vascular endothelial cells in culture and, in the presence of heparin, induces blood vessel growth in vivo. Partial Fibroblast growth factor (FGF) was originally identified in both pituitary (2) and whole brain (3). The growth factor activity was partially purified based on its ability to stimulate DNA synthesis in the immortal BALB/c 3T3 fibroblast cell line (4). Two mitogens, one acidic (5) and one basic (6), were subsequently identified in the partially purified brain FGF preparations. We previously reported the purification to apparent homogeneity and initial characterization of the approximately 17-kDa acidic FGF (aFGF) from bovine brain (7). A protein that may be similar, or identical, to the basic FGF found in brain has been purified from bovine pituitary (8, 9).With partially purified material, the presence of the acidic mitogenic activity for BALB/c 3T3 cells was observed to correlate with mitogenicity for vascular endothelial cells (6). We report here that aFGF is a potent mitogen for vascular endothelial cells in culture and induces the growth of blood vessels in vivo. Protein sequence data are also presented that uniquely identify this molecule and reveal homology with one type of interleukin 1 (IL-1). MATERIALS AND METHODSMitogenic Assays. Fetal bovine thoracic aortic endothelial cells (AG4762, National Institute of Aging Cell Repository, Institute for Medical Research, Camden, NJ) were assayed after 38 cumulative population doublings in vitro. The cells were plated in 6-well tissue culture dishes (Costar, Cam-bridge, MA) at 2 x 103 cells per cm2 in 1 ml of 20% heat-inactivated calf serum (GIBCO) in Dulbecco's modified Eagle's medium (DMEM; GIBCO) per well and changed to 1% serum 18 hr later. All media were supplemented with glutamine and penicillin/streptomycin as described (5). Either pure mitogen (7) diluted in 100 pl of 1 mg ofbovine serum albumin (Sigma) per ml of DMEM or serum samples were added to each well along with 1.6 puCi of [methyl-3H]thymidine (20.0 Ci/mmol, New England Nuclear; 1 Ci = 37 GBq) and 45 ,ug of unlabeled thymidine (Sigma) in 40 ,ul of DMEM. After a 48-hr incorporation period, the cells were washed and lysed, and 75% of the trichloroacetic acid-insoluble radiolabeled DNA was counted as described (5). The pure mitogen was found to be stable in the 7 mM trifluoroacetic acid/33% acetonitrile HPLC elution solvent (7) at -20°C under argon but lost substantial activity when lyophilized. Therefore, in all mitogenic and angiogenic assays, the pure mitogen was diluted from this solvent. Control assays showed that equivalent amounts of HPLC solvent components were innocuous.Mouse lung capillary endothelial cells (from T. Maciag, Revlon) were plated at 2.6 x 104 cells per cm2 in 24-well dishes (Costar) and grown to confluence in 0.5 ml of 10% charcoal-treated calf serum (HyClone, Logan, UT) in DMEM per well, lowered to 0.5% serum after 72 hr, and allowed to become quiescent over 48 hr. Eit...

Bovine brain-derived acidic fibroblast growth factor (aFGF) is a protein mitogen originally identified in partially purified preparations of whole brain. The protein was purified to homogeneity and shown to be a potent vascular endothelial cell mitogen in culture and angiogenic substance in vivo. The homology of aFGF to human interleukin-1 beta was inferred from partial sequence data. The complete amino acid sequence of aFGF has now been determined and observed to be similar to both basic FGF and interleukin-1's. A neuropeptide-like sequence, flanked by basic dipeptides, was observed within the aFGF sequence.

Rat liver poly(A-containing RNA greatly stimulated incorporation of radioactive amino acids into protein when added to a wheat germ in vitro translation system. Approximately 7% of the labeled synthetic product was precipitated following indirect immunoprecipitation with antisera to rat serum albumin. Analysis of this material, and of the cyanogen bromide fragments derived from it, by sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed that it contained an NH2-terminal extension of about 2500 daltons when compared to rat serum albumin. Automated sequence determination of purified cell-free product labeled with various radioactive amino acids revealed the presence of 18 additional amino acids NH2-terminal to the sequence of rat proalbumin. The partial sequence of this extension was found to be: Met-

The pI-6.8 species of normal human interleukin 1 (IL-1) has been isolated by ion-exchange and reverse-phase high-performance liquid chromatography. The isolated material had a molecular weight of 18,000, and had a specific bioactivity of 1.7 X 10(7) half-maximal U/mg in the murine thymocyte proliferation assay, values similar to those obtained for murine P388D1-derived IL-1 (12), and human IL-1 isolated by a previously published purification protocol (15). Amino-terminal sequence analysis revealed a single N-terminal, and resulted in the identification of 30 of the first 35 amino acid residues. Sequence of three CNBr cleavage fragments of purified IL-1 resulted in the identification of an additional 38 residues. All of the sequences agree exactly with those deduced from complementary DNA (cDNA) by Auron, et al. (18), demonstrating that this cloned cDNA, though considerably different from the cDNA reported for murine IL-1 (12), nevertheless codes for the pI-6.8 species of human IL-1. The evidence also shows that the precursor protein for human IL-1 is largely processed at the N-terminal end. Little or no processing occurs at the carboxy-terminal end. Sequence homology with interferon-inducing factor (26) suggests that the pI-6.8 species of human IL-1 is a member of a gene family. Although equally potent in the murine thymocyte proliferation assay, murine IL-1 and the pI-6.8 species of human IL-1 are structurally distinct. Further study will answer the interesting question as to the relationship of the other charged species of human IL-1 to these distinct IL-1 classes.

Most of the somatostatin-like activity from pigeon pancreas was found to correspond to a small species with an apparent molecular weight of 1500-2500. This species was isolated under conditions minimizing intermolecular interactions and protease activities. The isolated product was characterized by two somatostatin radioimmunoassays, a bioassay, endgroup determination, and amino acid analysis. The structure of the isolated compound was determined to be H-Ala-Glycyclo-(Cys-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys)-OH. Additionally, small amounts of des-Ala'-somatostatin, a possible degradation product of pancreatic somatostatin, and a large somatostatin-like species with an apparent molecular weight of 11,000-12,500 were detected. It is concluded that the main somatostatin-like polypeptide isolated from pigeon pancreas is identical to the mammalian hypothalamic tetradecapeptide somatostatin. In 1973, the amino acid sequence of somatostatin (SS) from ovine hypothalamus was reported (1, 2). The sequence for porcine hypothalamic SS was shown to be identical (3). Biologic and immunologic SS-like activities (SSLA) have also been detected in extrahypothalamic parts of the brain (4, 5), pancreas (6, 7), and gastrointestinal tract (7). Although these activities had been observed by bioassay and by immunologic techniques with several antisera directed against different portions of the SS molecule (8), the chemical identities of extrahypothalamic SS-like substances had not been established. In two earlier reports (9, 10) we described the initial purification of SS-like substances from pigeon pancreas, which was chosen as a source of extrahypothalamic SS-like species because of its high content of SSLA (8). We report here details of the isolation and characterization of SS from pigeon pancreas.METHODS AND MATERIALS Purification. Male pigeons were obtained from Carpenter Squab Ranch (Ventura, CA). For one experiment, 5-20 pigeons were decapitated. The pancreata were removed and submitted to either one of the following procedures:(A) The pancreata were frozen in liquid nitrogen within 1 min after removal from the animal. The frozen material was then pulverized in liquid nitrogen. The powder was almost totally dissolved in 8 M guanidine hydrochloride/2 M ammonium acetate, pH 2.5, at room temperature and centrifuged for 20 min at 48,000 X g. The supernatant was defatted with an equal volume of diethyl ether/hexane (2:1, vol/vol) and submitted to column chromatography (Bio-Gel P-100, Bio-Rad), which was performed in the presence of 6 M guanidine hydrochloride/i M ammonium acetate, pH 2.5. The chromatographic elution pattern was characterized by the following molecular weight markers: bovine serum gamma globulin, bovine ribonuclease A, cytochrome c (horse heart), lima bean trypsin inhibitor, bovine pancreatic trypsin inhibitor, porcine insulin, porcine '25I-labeled glucagon (New England Nuclear), [125I-Tyrl'SS, bacitracin, and tyrosine. All elution volumes were calculated as partition coefficients KD, referring to the ...

Retroviral proteins, including those from the human immunodeficiency virus (HIV), are synthesized as polyprotein precursors that require proteolytic cleavage to yield the mature viral proteins. A 99-residue polypeptide, encoded by the 5' end of the pol gene, has been proposed as the processing protease of HIV. The chemical synthesis of the 99-residue peptide was carried out by the solid-phase method, and the isolated product was found to exhibit specific proteolytic activity upon folding under reducing conditions. Upon size-exclusion chromatography, enzymatic activity was eluted at a point consistent with a dimeric molecular size. Specificity was demonstrated by the cleavage of the natural substrate HIV gag p55 into gag p24 and gag p17, as well as cleavage of small peptide substrates representing processing sites of HIV fusion proteins. The proteolytic action of the synthetic product could be inhibited by pepstatin, an aspartic protease inhibitor.