Identification of a critical ligand binding determinant of the human erythropoietin receptor. Evidence for common ligand binding motifs in the cytokine receptor family

The erythropoietin receptor (EPOR) is a member of a family of cytokine and growth factor receptors that share conserved features in their extracellular and cytoplasmic domains. We have used site-specific mutagenesis within the extracellular domain of the EPOR to search for amino acid residues involved in erythropoietin (EPO) binding. Mutant proteins were expressed in bacteria as soluble EPO binding proteins (EBP) and characterized for EPO binding activity in a number of different assays. Substitution of phenylalanine at position 93 (Phe93) with alanine (F93A mutation) resulted in a drastic reduction in EPO binding in the EBP. More conservative tyrosine or tryptophan substitutions at Phe93 resulted in much less dramatic effects on EPO binding. Biophysical studies indicated that the F93A mutation does not result in gross structural alterations in the EBP. Furthermore, the F93A mutation in full-length EPOR expressed in COS cells abolished detectable EPO binding. This was not a result of processing or transport defects, since mutant receptor was present on the surface of the cells. Mutations in the region immediately around Phe93 and in residues homologous to other reported ligand binding determinants of the cytokine receptor family had small to moderate effects on EPO binding. These data indicate that Phe93 is a critical EPO binding determinant of the EPOR. Furthermore, since Phe93 aligns with critical ligand binding determinants in other receptors of the cytokine receptor family, these data suggest that receptors of this family may use common structural motifs to bind their cognate ligands.

In vivo and in vitro reactions of toluene diisocyanate isomers with guinea pig hemoglobin

Guinea pig hemoglobin (Hb) adducts of 2,4- and 2,6-toluene diisocyanate (2,4- and 2,6-TDI) were individually prepared, each at a Hb tetramer to diisocyanate ratio of 1:1, and compared with adducts of Hb from animals exposed to 1 ppm 2,4-TDI vapor. Each Hb sample was subjected to C4 HPLC chain/heme separation with UV detection. Survey of the LC fractions using an antiserum prepared to a heterologous TDI-protein indicated a difference in chain specificity and product types formed in vitro by the two isomers. Ionspray mass spectrometry (MS) revealed the chemistry of the adduction products. Carbamoylated products, formed from adduction by one TDI molecule (with one isocyanato group hydrolyzed to an amino group), were detected by MS with 2,4-TDI on each chain and with 2,6-TDI on the beta chain. Additionally, a quasi-molecular ion of a bis carbamoylation adduct was noted by MS in the in vitro 2,4-TDI-Hb adduct in the form of TDI-cross-linked alpha and beta chains. Ionspray MS analysis of the Hb isolated from guinea pigs exposed in vivo to 2,4-TDI indicated carbamoylation products with both the alpha and beta chains in which one of the two original isocyanato groups had been hydrolyzed to the amine. We also found evidence of an amine-nitroso adduct on the alpha chain in the in vivo sample. These results indicate that at least one of the isocyanato moieties (or a masked derivative) of 2,4-TDI survived passage through the lung, into the serum, and through the erythrocyte membrane to form adducts with Hb that were stable to dialysis, gel filtration, and reversed phase HPLC separation under acidic conditions. The presence of an apparent amine-nitroso adduct indicated in vivo formation of 2,4-diaminotoluene, a recognized animal carcinogen.

A search for persistent rubella virus infection in persons with chronic symptoms after rubella and rubella immunization and in patients with juvenile rheumatoid arthritis

Peripheral blood polymorphonuclear leukocytes, mononuclear cells, and plasma and nasopharyngeal specimens were obtained from 6 subjects with persistent symptoms following rubella immunization, 1 subject with persistent symptoms following rubella, 11 children with juvenile rheumatoid arthritis, 17 recently immunized control subjects, and 1 control subject with acute clinical rubella. Rubella virus was isolated from the blood or nasopharynx of four of the 18 control subjects. In contrast, rubella virus was not recovered from any specimens from the seven subjects with persistent symptoms following immunization or natural infection or from the 11 children with juvenile rheumatoid arthritis. A polymerase chain reaction assay detected rubella virus in the blood from three of 14 control subjects but not in the blood from two subjects with persistent symptoms following rubella immunization or in that from three children with juvenile rheumatoid arthritis. We have not been able to confirm the findings of others who have reportedly recovered rubella virus from lymphocytes of persons with persistent symptoms following rubella or rubella immunization.

Effects of Chinese herbs on macrophage functions in N-butyl-N-butanolnitrosoamine treated mice

We investigated the effect of Chinese herbs Lithospermi radix, Astragali radix and Cnidii rhizoma on the functions of macrophages obtained from mice treated with the carcinogen N-butyl-N-butanolnitrosoamine (BBN). The chemotactic activity of murine macrophages was significantly decreased by 17 weeks of treatment with BBN compared with controls. Production of IL-1 and TNF was also markedly reduced. Treatment with Lithospermi radix, Astragali radix, and Cnidii rhizoma significantly inhibited BBN-induced suppression chemotactic activity and production of IL-1 and TNF-alpha by macrophages. Moreover, we found that Astragali radix treated macrophage chemotaxis, it or Cnidii rhizoma induced productions of TNF-alpha were in excess of control.

Effect of shi-ka-ron on cytokine production of lymphocytes in mice treated with cyclophosphamide

The effect of Shi-ka-ron (CX) on cytokine production of lymphocytes in mice treated with cyclophosphamide was investigated. Shi-ka-ron, a traditional Chinese prescription, consists of 8 crude Chinese herbal extracts. Its main efficacy is to strengthen the body resistance. We observed that each CX component stimulated interleukine-2 and interferon-gamma production of murine splenic lymphocytes both in vitro and in vivo. IL-2 and IFN-gamma production of splenic lymphocytes were also examined in mice treated with CX combined with cyclophosphamide (CY) in vivo. We found that CX not only could increase IL-2 and IFN-gamma production in vitro, but also in vivo at suboptimal concentration.

Modulation of the rat tumor-associated shedding antigen (CE7) and augmentation of immunogenicity by irradiation

We have previously reported that rat fibrosarcoma KMT-17 cells and their in vitro counterparts, cloned A3 cells, shed a tumor-associated antigen (TAA), termed CE7, from the cell surface on vesicular membranes, under growth-enhancing conditions. This study shows that irradiation (1 approximately Gy) from a 60Co source, inhibited A3 cell growth dose-dependently and correspondingly increased CE7 expression by A3 cells as determined by anti-CE7 monoclonal antibody using flow cytometry. CE7 expression gradually increased with increasing doses of irradiation and reached a peak level at 30Gy. After 30Gy irradiation, CE7 expressing A3 cells were fixed with 1% paraformaldehyde and were used to intradermally immunize syngenic rats. Immunized rats developed transplantation resistance to the parent KMT-17 cells as compared to rats immunized with unirradiated A3 cells. Rat MHC class 1 antigen expression was slightly decreased by irradiation and therefore, resistance to tumor transplantation appeared to arise solely due to the enhancing effects of irradiation on TAA expression which increases the antigenicity of the tumor cells coverting them to an effective stimulator of antitumor effector cells. This phenomenon may offer a possibility of the resistance to the re-emergence and metastasis of the tumor like a KMT-17 through the induction of antitumor memory cells.

Virucidal short wavelength ultraviolet light treatment of plasma and factor VIII concentrate: protection of proteins by antioxidants

The use of solvent/detergent mixtures and various forms of heat treatment to inactivate viruses has become widespread in the preparation of blood derivatives. Because viruses that lack lipid envelopes and/or are heat resistant, eg, hepatitis A virus (HAV) or parvovirus B19 may be present, the use of two methods of virus elimination that operate by different mechanisms has been advocated. We now report on short wavelength ultraviolet light (UVC) irradiation for virus inactivation and enhancement of its compatibility with proteins by quenchers of reactive oxygen species (ROS). Treatment of an antihemophilic factor (AHF) concentrate or whole plasma with 0.1 J/cm2 inactivated 10(5) to > or = 10(6) infectious doses (ID) of encephalomyocarditis virus (EMCV), HAV, bacteriophage M13, vesicular stomatitis virus (VSV), and porcine parvovirus. However, the recovery of factor VIII was 30% or lower on treatment of an AHF concentrate and 60% on treatment of plasma. Factor VIII recovery could be increased with little or no effect on virus kill by addition of rutin, a flavonoid known to quench both type I and type II ROS. On treatment of plasma in the presence of rutin, the recovery of several other coagulation factors was also enhanced by rutin addition and typically exceeded 75%. Electrophoretic analysis of treated AHF concentrate confirmed the advantage of rutin presence; UVC irradiation of plasma did not cause discernible changes in electrophoretic banding patterns, even in the absence of rutin. We conclude that addition of UVC treatment to existing processes used in the manufacture of blood derivatives will provide an added margin of safety, especially for nonenveloped or heat-stable viruses.

[Expression of proliferating cell nuclear antigen in the liver tissue of hepatitis B patients]

Liver biopsy and autopsy specimens of 153 cases, including 39 cases of acute severe hepatitis (ASH), 21 cases of subacute severe hepatitis (SSH), 11 cases of chronic severe hepatitis (CSH), 22 cases of active cirrhosis (AC), 20 cases of acute mild (AMH), chronic persistent (CPH) and active hepatitis (CAH), respectively, were immunohistochemically stained for proliferating cell nuclear antigen (PCNA) to compare the proliferative activity of hepatocytes by using labelling index (LI). LI is higher in CAH, SSH, and AMH than in AC and CSH (P < 0.01). In the latter, LI was completely negative in most of the specimens (25/33, 75.8%) and few scattered hepatocytes positive for PCNA were found in the remaining 8 cases (8/33, 24.2%) in the area next to the fibrotic septum and varied greatly in different pseudolobules. The results showed that the proliferative activity was very low in the AC and CSH. In some cases of ASH, the residual hepatocytes still kept prominent proliferating ability; it meant that the survived percentage would have been increased with regeneration of hepatocytes if those patients had not died early. In ASH and SSH, LI was significantly higher in patients who survived than in those who died (P < 0.01). The detection of PCNA in liver tissue with severe viral hepatitis is useful for prognostic evaluation.

Evidence for contact between the cyclic AMP receptor protein and the delta 70 subunit of Escherichia coli RNA polymerase

The loop at the 52-position of the cAMP receptor protein (CRP) has been suggested as a potential site for contacting RNA polymerase on Class II promoters where the CRP binding site is located at position -41.5 (Bell, A., Gaston, K., Williams, R., Chapman, K., Kolb, A., Buc, H., Minchin, S., Williams, J., and Busby, S. (1990) Nucleic Acids Res. 18, 7243-7250). Using protein-protein photo-cross-linking, evidence is presented showing that the 52-loop of CRP is in physical proximity to the delta subunit of RNA polymerase holoenzyme. This interaction required the presence of a functional preinitiation complex. The CRP suppressor mutation, K52N, increased the efficiency of cross-linking, indicating an improved physical interaction between the CRP 52-loop and the delta subunit. Evidence for direct interaction between the CRP 156-162 loop and delta subunit of RNA polymerase on both gal and lac promoters are also provided. The data indicate that CRP bound to the gal promoter contacts both the alpha and delta 70 subunits of RNA polymerase.

[Chemical constituents of Euphorbia nematocypha Hand.-Mazz]

Four compounds were isolated from the roots of Euphorbia nematocypha. Three of them were identified as A'-neogammacer-22(29)-en-3 beta-ol (18 beta.21 alpha) (II), jolkinolide E (III) and beta-sitoesterol (IV). Among them, II was obtained from the genus Euphorbia and III from this plant for the first time.

[Effects of shi-ka-ron and Chinese herbs in mice treated with anti-tumor agent mitomycin C]

The Shi-ka-Ron, and its constituent Chinese herbs Lithospermum erythrorhizon, Astragalus membranaceus and Ligusticum Wallichii were administered with antitumor agent, mitomycin C (MMC) to ICR mice, and their effects on murine macrophages and lymphocytes were studied. Peritoneal macrophages were significantly inhibited both in their number and chemotactic activity by MMC treatment. Splenic weight and blastogenic responsiveness to Concanavalin A of spleen lymphocytes also decreased significantly in MMC-treated mice. NK cell activity was also suppressed by MMC treatment. When these mice were orally treated with extracts of Shi-ka-ron or each Chinese herbs mentioned above, it showed protective effects to immunosuppressive mice on all 5 items studied. The number of macrophages, and the functions of macrophages and lymphocytes maintained the same or more than normal levels in MMC plus each group of these extracts treated mice. These results suggest that the Shi-Ka-Ron and Chinese herbs could resist immunosuppression induced by antitumor agent MMC, and its mechanisms might be correlated with stimulation of the RES (reticuloendothelial system), activation of T cell blastogenesis and NK cell cytotoxicity.

[Taxonomic studies on original plants of radix Euphorbiae ebracteolatae]

It has been discovered through investigation across the country that, thus far, the Radix Euphorbiae Ebracteolatae is derived from 12 species (varieties, forms) of 3 families. Their classification characters are discussed and a key is given in this paper.

Epitope mapping and functional characterization of monoclonal antibodies specific for the alpha subunit of Escherichia coli RNA polymerase

The epitopes have been localized for a set of monoclonal antibodies specific for the alpha subunit of the Escherichia coli RNA polymerase. The antibodies are classified into three groups based on their epitopic assignments. Group 1, mAb 123C2, maps in the N terminus of alpha between amino acids 1 and 23; Group 2 antibodies (mAb 129C4, mAb 124D1 and mAb 121C5) map in the central region between amino acids 190 and 210; Group 3 antibodies (mAb 130B1 and mAb 125C6) map in the C terminus between amino acids 310 and 320. mAb 130C2 is anomalous since it maps to the N terminus between amino acids 1 and 23 as well as to the C terminus between amino acids 320 and 329. The antibodies were used to investigate the role of alpha in transcription activation with cAMP receptor protein-dependent promoters. Three antibodies (130C2, 121C5, and 125C6) inhibited cAMP receptor protein-dependent initiation with lac P+ but not with lac UV5 or gal P+. Inhibition was observed with free RNA polymerase and the closed promoter complex; the preformed open promoter complex was insensitive. Only lac P+ was sensitive to these anti-alpha antibodies supporting the concept that the mode of interaction of RNA polymerase with cAMP receptor protein differs between lac P+ and gal P+.

[Immunomodulative effects of Chinese herbs in mice treated with anti-tumor agent cyclophosphamide]

Extracts of Chinese herbs were administered with antitumor agent, cyclophosphamide (CY), and their effects on macrophages and lymphocytes were studied. Number of peritoneal macrophages significantly decreased and their chemotactic activity was suppressed by treatment with CY. Blastogenic responsiveness to Concanavalin A and NK cell activity of spleen lymphocytes were suppressed significantly in CY-treated mice. Extracts of Lithospermi radix, Astragali radix and Glycyrrhizae radix showed protective effects on immunosuppressive mice. The number of macrophages, chemotactic activity of macrophages and blastogenic response of lymphocytes were recovered to the same or more than that of normal levels. An extract of Ginseng radix showed protective effects on the number and functions of macrophages by treatment with CY but did not show any effects on the lymphocytic blastogenesis. On the contrary it showed a strong inhibitory effect on the NK cell activity. These results suggest that Chinese herbs could modulate cellular immune response, especially in the activation of macrophages and splenic lymphocytes.

Effect of shi-ka-ron and Chinese herbs on cytokine production of macrophage in immunocompromised mice

Shi-Ka-Ron is a prescription composed of 8 crude extracts of Chinese herbs. It reduces suppression of cytokine production by peritoneal macrophages in mice Immunocompromised by the anti-tumor agent, cyclophosphamide (CY), in vivo. Although it dose not increase IL-1 production in vitro, it enhances TNF production. We found that Ginseng radix, Lithospermi radix, Astragli radix and Glycyrrhizae radix somewhat reduced suppression of cytokine production in CY treated macrophages. Especially, Glycyrrhizae radix shows an active immune response both in vivo and in vitro. Our results suggested that the mechanism underlying immunomodulation of Shi-Ka-Ron is closely related to cytokine production: each herb stimulating macrophages.

Comparative spectroscopic, calorimetric, and computational studies of nucleic acid complexes with 2',5"-versus 3',5"-phosphodiester linkages

We have used a combination of spectroscopic, calorimetric, and computational techniques to characterize the properties of nucleic acid complexes with 2',5''- and 3',5''-phosphodiester linkages. Specifically, we have compared the properties of complexes formed by the association of 3',5'' single-stranded 16-mers of adenylic acid (A16) and thymidylic acid (T16) with the complexes formed by the corresponding single-stranded 16-mers with 2',5''-phosphodiester linkages (A*16 and T*16). Our results reveal the following differential features: (i) the 3',5'' strands form either a duplex or a triplex, depending on the sodium ion concentration, whereas the 2',5'' strands form either a triplex or no complex at all; (ii) the 2',5'' and 3',5'' triplexes exhibit significantly different CD spectra, suggesting that the two triplex states are conformationally nonequivalent; (iii) the 2',5'' triplex has a lower charge density than the 3',5'' triplex; (iv) the thermal stability of the 3',5'' triplex, as expected, is concentration dependent, whereas the thermal stability of the 2',5'' triplex is concentration independent; (v) relative to their component single strands, the 2',5'' triplex is thermodynamically much less stable than the 3',5'' triplex, despite being thermally more stable; (vi) the reduced thermodynamic stability of the 2',5'' triplex relative to the 3',5'' triplex is overwhelmingly enthalpic in origin. In the aggregate, our results reveal and characterize significant differences in the properties of complexes formed by the association of strands with identical base sequences but different phosphodiester linkages. We describe a structural model that is consistent with many of the differential properties observed. We also speculate on how these differential properties may have provided an evolutionary advantage for 3',5'' linkages and how the properties of 2',5'' complexes might be exploited in antisense strategies.

Toluene diisocyanate protein adducts in the bronchoalveolar lavage of guinea pigs exposed to vapors of the chemical

To investigate the process of toluene diisocyanate (TDI) sensitization, studies were conducted to identify TDI-protein adducts in the bronchoalveolar lavage (BAL) fluid of guinea pigs exposed to a sensitizing atmosphere of the commercially used 4:1 mixture of 2,4- and 2,6-TDI. Animals were exposed to 2 ppm TDI for 3 h. Immediately thereafter lungs were lavaged. TDI-modified proteins in the lavage fluid were identified by immunologic staining with a highly sensitive and specific rabbit antiserum raised to a TDI-keyhole limpet hemocyanin (TDI-KLH) conjugate. The sensitivity of the antiserum was demonstrated by its ability to identify TDI-guinea pig serum albumin (GSA) adducts with as few as 0.7 mol of TDI/mol of protein. The antiserum did not react with GSA nor with a GSA adducted with another aromatic diisocyanate, diphenylmethane 4,4'-diisocyanate. TDI-protein adducts in the BAL fluid were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by immunoblotting with use of the rabbit anti TDI-KLH antiserum. At least 5 protein bands were recognized by the antiserum. Electrophoretic mobilities indicated molecular sizes equivalent to 10.5, 38, 45, 66, and 148 kDa. Employing a murine anti-GSA antibody in immunoaffinity chromatography, one of the proteins in the 66-kDa band was identified as serum albumin. Attempts to purify the TDI-albumin adduct using a Cibacron-Sepharose column were unsuccessful. Studies with a model TDI0.7-GSA conjugate (which contained an average of 0.7 mol of TDI/mol of GSA) indicated that the TDI-albumin was not retained by the triazine dye column unless the adducted protein was first reduced by incubation with mercaptoethanol.(ABSTRACT TRUNCATED AT 250 WORDS)