Elimination of goat haemoglobin and its complexes with goat haptoglobin from goat and rat circulation

The rate of elimination from rat and goat circulation of 125I-labelled goat haemoglobin and its complexes with human and goat haptoglobin in goat circulation, was studied. The half-life time t1/2 of haemoglobin in rat circulation was 1.5h, whereas in goat circulation -- 4 h, and was 10 times shorter than t1/2 for its complexes.     

Degradation and inactivation of ceruloplasmin and haptoglobin by rat liver lysosomes and some other proteinases

Lysosomal fraction was isolated from rat liver by density gradient centrifugation after pervious loading of lysosomes in vivo with Triton WR-1339. Tritosome preparations were incubated at 37 degrees C and pH 5 for 24 hr with purified human ceruloplasmin or haptoglobin. After this period approximately 20% of total alpha amino nitrogen was released from ceruloplasmin and over 40% from haptoglobin. This was accompanied by loss of peroxidase activity of haptoglobin (in complex with haemoglobin), while enzymatic activity of ceruloplasmin remained unaltered. Removal of sialic acid by neuraminidase had no effect on digestion of ceruloplasmin by rat liver tritosomes. Both glycoproteins were resistant to horse leucocyte proteinases and pancreatic eleastase but were easily inactivated by trypsin and chymotrypsin.     

Immunochemical characteristics of the ovine polymeric haptoglobin HpC

It was found that haptoglobins of camel, cattle, horse, pig, rat, guinea pig and man form upon immunoelectrophoresis precipitation arcs with antibodies against polymeric sheep haptoglobin C, corresponding to alpha 2-globulins. The immunocrossreactivity of haptoglobins of man and various animal species towards antibody to sheep haptoglobin (100, 88.0, 75.2, 72.1, 56.3, 51.0, 41.3 and 28.0% for haptoglobin of sheep, camel, pig, cattle, man, rat, guinea pig and horse, respectively) was determined. The intensity of crossreactions between sheep haptoglobin and the proteins under study towards antibody to haptoglobin C reflects the similarity of their primary structure and, consequently, the immune homology of their molecules. Using quantitative titration, the antigenic valency values for human (6), sheep (5), cattle (4) and horse (3) haptoglobins were determined.     

Hemoglobin-haptoglobin receptor in rat liver plasma membrane

The presence of a receptor specific for the hemoglobin . haptoglobin complex is demonstrated in rat liver plasma membranes. Hemoglobin . haptoglobin complex, administered intravenously to rats, was cleared from the circulation at a constant rate with exclusive incorporation of the molecule into hepatocytes. This incorporation was unaffected by the simultaneous injection of asialoglycoprotein or heme . hemopexin complex. In vitro experiments with isolated liver plasma membranes indicated the absence of competitive binding of these molecules to the membrane and suggested that this receptor might recognize an altered conformation of the haptoglobin moiety of the complex resulting from the binding with hemoglobin. These observations suggest that the mechanism of recognition and binding of hemoglobin . haptoglobin complex by the receptor is different from that of the asialoglycoprotein receptor or heme . hemopexin receptor.     

Effect of inhibited endocytosis in sinusoidal liver cells on catabolism of equine haptoglobin and haemoglobin in the hen

Catabolism of equine haptoglobin (Hp), haptoglobin-haemoglobin complex (Hp-Hb) and haemoglobin (Hb) in the hen was studied in the liver reticuloendothelial system (RES) in which endocytosis of protein was inhibited by aggregated denatured albumin (Agr-Alb). Intravenous injection of Agr-Alb together with equine [125I]Hp, [125I]Hp-Hb or [125I]Hb partially inhibited elimination of these proteins from hen circulation. The decrease of clearance was less pronounced when the labelled proteins were introduced 30 min after Agr-Alb injection due to stimulation of phagocytosis in RES by Agr-Alb. Elimination of equine proteins (Hp, Hp-Hb and Hb) from hen circulation by RES is only one of the possible metabolic fates of these proteins.     

Corticotropin releasing factor (CRF)-like immunoreactivity in the hypothalamus and posterior pituitary of the goat, bovine, rat, monkey and human

Goat hypothalamic extract prepared by HCl extraction and chromatographed on a Sephadex G-50 column showed two immunoreactive CRF peaks. Most of the immunoreactivity coeluted with synthetic ovine CRF, and a small peak eluted near the void volume. Bovine, monkey, rat and human hypothalamic extracts prepared by acid-acetone or acid-methanol extraction showed three immunoreactive peaks. Most of the immunoreactivity coeluted with ovine CRF, and other smaller peaks eluted near the void volume and slightly before arginine vasopressin. Goat hypothalamic extract showed the highest cross-reactivity with anti-ovine CRF serum, followed by bovine hypothalamic extract. Less cross-reactivity was found in human, rat and monkey hypothalamic extracts. CRF immunoreactivity in goat hypothalamic extract coeluted with ovine CRF on reversed phase high performance liquid chromatography (HPLC) and main CRF immunoreactivity in human and rat hypothalamic extracts eluted slightly later than ovine CRF. These results suggest that there is a heterogeneity among the CRF molecules in these species and that goat CRF may be more similar to that of sheep CRF and the amino acid sequence or molecular weight of other animals CRF may be different from that of sheep CRF. The monkey posterior pituitary and rat neurointermediate lobe showed similar elution patterns of CRF immunoreactivity to their hypothalamic extracts on Sephadex gel filtration and HPLC. These results indicate that the posterior pituitary contains a similar CRF to hypothalamic CRF.     

Studies on the binding of haemoglobin by haptoglobin using electrofocusing and gradient electrophoresis.

1. Gel electrofocusing followed by gel gradient electrophoresis separated the haptoglobins and their complexes with haemoglobin into characteristic two-dimensional patterns of protein bands. 2. Molecular weights of 107 000, 139 000 and 168 000 were obtained for the three bands seen after a purified preparation of haptoglobin type 1 was partially saturated with haemoglobin. This indicated that free haptoglobin, the intermediate haptoglobin-haemoglobin complex containing one half-haemoglobin and the saturated complex with two half-haemoglobins were present. 3. The three proteins showed considerable microheterogeneity and gave a number of isoelectric points in the pH ranges 4.58-4.77, 5.20-5.40 and 5.74-5.93, free haptoglobin type 1 being the lowest group. These ranges were all 0.15-0.30pH units lower if other values were taken for the isoelectric points of markers used to calibrate the pH gradient. 4. All three proteins were present over a wide range of haemoglobin concentrations, from 0.5% to 92% of that required for saturation. This would be expected if both binding sites have similar affinities for haemoglobin.     

Human haptoglobin binds to human myoglobin

Human myoglobin, obtained from human heart, was purified to homogeneity by salt precipitation, crystallization and ion-exchange chromatography. Trace contamination by haemoglobin, if any, was removed by repeated adsorption on an immunoadsorbent of anti-haemoglobin antibodies. The interaction between human haptoglobin and human myoglobin was investigated by a solid-phase radioimmunoassay. Myoglobin adsorbents bound 125I-labelled haptoglobin in a specific manner. Linear Scatchard plots of the data indicate that human myoglobin has only one binding site for haptoglobin in terms of the binding affinity (Ka = 8.5 X 10(6) M-1). These results suggest that haptoglobin not only binds haemoglobin but also binds human myoglobin, although with an affinity that is much lower than that of haemoglobin. The physiological significance of this interaction is discussed.     

Monoclonal antibody to human haptoglobin reacts with goat haptoglobin.

1. Monoclonal antibody 2.36.71.41 produced to human haptoglobin forms precipitates with goat haptoglobin in double immunodiffusion and electroimmunodiffusion. 2. Solid-phase immunoenzymatic assay (ELISA) based on the reaction of the monoclonal antibody 2.36.71.41 with goat haptoglobin can be used for quantitative estimation of haptoglobin content in goat sera. 3. The minimum detectable concentration of goat haptoglobin is 0.03 micrograms/ml.     

Oxygen-binding and immunological properties of complexes between dextran and animal haemoglobins.

Complexes of dextran 20 000 with haemoglobins of sheep, rabbit, dog, bovine and human origin were prepared through alkylation of haemoglobin by N-bromoacetylaminoethylamino-dextran. The yields were uniformly high. Complex-formation in each case was accompanied by the disappearance of reactive thiol groups on the haemoglobin, and by an increase in the affinity of the haemoglobin for oxygen. The immunological properties of dog, rabbit and sheep dextran-haemoglobin were investigated in both homologous and heterologous species. The complexes were found to be non-immunogenic in the homologous species. In heterologous species the anti-haemoglobin response induced by each complex was generally of a similar level to that induced by the haemoglobin alone.     

Haemoglobin binding with haptoglobin. Localization of the haptoglobin-binding sites on the beta-chain of human haemoglobin by synthetic overlapping peptides encompassing the entire chain.

A synthetic approach was employed to identify the haptoglobin-binding sites on the beta-chain of human haemoglobin. This approach consists of the synthesis of a series of consecutive overlapping peptides that, together, systematically represent the entire protein chain. Fourteen synthetic peptides (beta 1-15, beta 11-25 etc.) were examined for their ability to bind human haptoglobin by quantitative solid-phase radiometric titrations of 125I-labelled haptoglobin. Of these 14 peptides only peptides beta 11-25 and beta 131-146 bound haptoglobin significantly; peptide beta 21-35 exhibited a small binding activity as a consequence of the overlap with peptide beta 11-25. On this basis and by examination of the three-dimensional structure of haemoglobin, it was concluded that the beta-chain of haemoglobin has two binding sites for haptoglobin that reside in, but do not necessarily encompass all of, the regions beta 11-25 and beta 131-146.     

A simple method for measurement of the haemoglobin binding capacity of canine haptoglobin

The potential of a series of related compounds to induce haemolytic anaemia in dogs highlighted the need for a reliable and sensitive technique to identify changes in plasma haptoglobin concentration. An indirect method established for human samples was adapted for use with canine plasma. This method measures the haemoglobin binding capacity of plasma, which is directly proportional to the functional haptoglobin concentration. The efficacy of this technique was investigated on samples taken from Beagle dogs which had previously received small quantities of water intravenously. A substantial reduction in haemoglobin binding capacity was recorded before other haematological parameters were significantly affected. It was concluded that measurement of haemoglobin binding capacity by this method provides a valid reflection of haptoglobin status in the dog.     

Comparative studies on the gastric glycopeptide in eleven animal species.

1. Glycopeptides in the stomachs of eleven mammalian species, including human, rabbit, horse, cow, pig, goat, sheep, dog, cat, guinea pig and rat were assayed by determining the carbohydrate content of materials which remained after proteolysis. 2. The glycopeptide content was higher in the mucosa than in the muscular layer including serosa, especially in the porcine stomach and the fourth stomachs of the ruminants than in the stomachs of any other animals. 3. The glycopeptide, which was stained with both alcian blue and PAS, was absent or sparingly present in the mucosae of the human, rabbit, horse stomachs and in the mucosae of the first to third stomachs of the cow, goat and sheep, whereas in the mucosae of the pig, dog, cat, guinea pig and rat stomachs and in the mucosae of the fourth stomachs of the cow, goat and sheep, it was found in noticeable extents.     

Immunochemistry of prostaglandin endoperoxide-forming cyclooxygenases: the detection of the cyclooxygenases in rat, rabbit, and guinea pig kidneys by immunofluorescence.

Rabbit antiserum has been prepared against the prostaglandin endoperoxide-forming cyclooxygenase (EC 1.14.99.1) purified from sheep vesicular glands. Ouchterlony double diffusion and immunoelectrophoretic analyses indicate that the anti-cyclooxygenase serum is monospecific for the enzyme. The anti-cyclooxygenase serum reacts with both active and inactivated forms of the sheep vesicular gland (SVG) cyclooxygenase. Furthermore, the immune serum precipitates solubilized microsomal cyclooxygenases from each of six other tissues examined, including bovine seminal vesicle, rabbit kidney medulla, guinea pig lung, dog spleen, sheep uterus, and human platelets. Anti-SVG cyclooxygenase serum was used in combination with fluorescein isothiocyanate )FITC)-labeled goat anti-rabbit IgG to detect cyclooxygenases in cryostat sections from rat, rabbit and guinea pig kidneys by immunofluorescence. Highly prominent fluorescence was associated only with the epithelial cells lining the collecting ducts in rabbit and guinea pig kidneys, and except for the nucleus, was uniformly distributed within the interior of these cells. In rat kidney, fluorescence was detected not only in collecting tubules but also in the interstitial cells of the renal papilla. Our results are consistent with the emerging hypothesis that PGE2 produced intrarenally plays a physiological role in natriuresis.     

Calorimetric studies of the haemoglobin–haptoglobin reaction

Haptoglobin binds haemoglobin so firmly that there is practically no dissociation. It would be expected that the heat of the reaction would be relatively large. The development of the microcalorimeter by Benzinger offered the opportunity to measure the heat of reaction. The experiments were carried out in the Beckman 190B Microcalorimeter in two ways: (1) a constant amount of haptoglobin (Kabi; 65mg.) with different amounts of haemoglobin, and (2) a constant amount of haemoglobin (32.5mg.) with different amounts of haptoglobin. The proteins, each in 5ml. of 0.15m-phosphate buffer, pH7.4, were placed in equal-volume calorimeter cells. The heat produced/mg. of haemoglobin was calculated from the slope of the curve for a constant amount of haptoglobin and from the maximum heat for a constant amount of haemoglobin. This heat is about 70kcal./mole at 37 degrees . DeltaH varies with temperature, being -70.2 at 37 degrees , -29.7 at 20 degrees and 7.2 at 4 degrees . From the amount of haptoglobin required to attain maximum heat with 32.5mg. of haemoglobin and the amount of haemoglobin required to attain maximum heat with 65mg. of haptoglobin, it appears that at excess of haptoglobin there is competition between the reactions of 2moles of haptoglobin with 1mole of haemoglobin (or 2 alphabeta-chains) and 1mole of haptoglobin with 1mole of haemoglobin.     

Haemoglobin binding with haptoglobin. Unequivocal demonstration that the beta-chains of human haemoglobin bind to haptoglobin.

Haptoglobin binding to haemoglobin and its isolated alpha- and beta-chains was studied by use of a highly sensitive solid-phase radiometric assay. As expected, adsorbents of haemoglobin bound 125I-labelled haptoglobin more efficiently than did adsorbents of the alpha-chain. However, unexpectedly, adsorbents of the beta-chain were found to be essentially identical with those of the alpha-chain in their ability to bind haptoglobin. These results demonstrate, unequivocally, the ability of beta-chains to bind to haptoglobin, and indicate that this assay is particularly convenient and useful for studying haptoglobin interactions with haemoglobin and its alpha- and beta-chains.     

Immunochemistry of prostaglandin endoperoxide-forming cyclooxygenases: The detection of the cyclooxygenases in rat, rabbit, and guinea pig kidneys by immunofluorescence

Rabbit antiserum has been prepared against the prostaglandin endoperoxide-forming cyclooxygenase (EC 1.14.99.1) purified from sheep vesicular glands. Ouchterlony doùble diffusion and immunoelectrophoretic analyses indicate that the anti-cyclooxygenase serum is monospecific for the enzyme. The anti-cyclooxygenase serum reacts with both active and inactivated forms of the sheep vesicular gland (SVG) cyclooxygenase. Furthermore, the immune serum precipitates solubilized microsomal cyclooxygenase from each of six other tissues examined, including bovine seminal vesicles, rabbit kidney medulla, guinea pig lung, dog spleen, sheep uterus, and human platelets.Anti-SVG cyclooxygenase serum was used in combination with fluoresence isothiocyanate (FITC)-labelled goat anti-rabbit IgG to detect cyclooxygenase in cryostat sections from rat, rabbit and guinea pig kidneys by immunofluorescence. Highly prominent fluorescence was associated only with the epithelial cells lining the collecting ducts in rabbit and guinea pig kidneys, and except for the nucleus, was uniformly distributed within the interior of these cells. In rat kidney, fluorescence was detected not only in collecting tubules but also in the interstitial cells of the renal papilla. Our results are consistent with the emerging hypothesis that PGE₂ produced intrarenally plays a physiological role in natriuresis.     

Oleacein enhances anti-inflammatory activity of human macrophages by increasing CD163 receptor expression

BackgroundOleacein (dialdehydic form of decarboxymethyl elenolic acid linked to hydroxytyrosol; 3,4-DHPEA-EDA) have been proven to possess antioxidant and anti-inflammatory activity.PurposeIn this study, we examined whether oleacein could increase CD163 and IL-10 receptor expression as well as HO-1 intracellular secretion in human macrophages.MethodsEffect of oleacein (10 and 20 μmol/l) or oleacein together with complexes of haemoglobin (Hb) and haptoglobin 1-1 (Hp11) or haptoglobin 2-2 (Hp22) on expression of IL-10 and CD163 receptor was determined by Flow Cytometry. Expression of CD163mRNA was measured by real-time quantitative RT-PCR. Heme oxygenase 1 (HO-1) intracellular secretion in macrophages was investigated by enzyme-linked immunosorbent assay (ELISA).ResultsOleacein (OC) together with complexes HbHp11 or HbHp22 stimulated the expression of CD163 (30-100-fold), IL-10 (170-300-fold) and HO-1 secretion (60-130-fold) after 5 days of coincubation. The 2-fold (24 h), 4-fold (48 h) increase of CD163 mRNA level and its final (72 h) decrease was also observed.ConclusionOur results suggested that oleacein enhances anti-inflammatory activity of complexes haemoglobin with haptoglobin 1-1 and 2-2 and could play a potential role in the prevention of inflammatory disease related to atherosclerosis.     

A comparative study of Echinococcus granulosus from human and animal hosts in Kenya using isoelectric focusing and isoenzyme analysis

Macpherson C. N. L. and Mcmanus D. P. 1982). A comparative study of Echinococcus granulosus from human and animal hosts in Kenya using isoelectric focusing and isoenzyme analysis. International Journal for Parasitology12: 515–521. The soluble enzyme extracts from protoscoleces obtained from hydatid cysts of human, camel, cattle, sheep and goat origin were compared on the basis of their isoenzyme patterns for GPI and PGM using isoelectric focusing. Consistent GPI and PGM isoenzyme patterns were obtained for larvae of human, camel and sheep material. Cattle material varied occasionally in having an additional cathodic band in some of the GPI patterns. Two distinct isoenzyme patterns were evident in the goat material for both enzymes. The more common goat patterns were similar to those of human, cattle and sheep (Kenya, U.K. and Argentina) material, which were similar to each other. The rare goat patterns were similar to those obtained for camel material. Cyst location in the various intermediate hosts had no effect on the zymograms obtained. Additionally, no alteration in the major banding patterns was observed between the larvae and homologous adults produced by experimental infections. Of 26 naturally infected dogs, 19 produced adult GPI zymograms resembling human/ sheep/goat (common form) experimental infection patterns, three were similar to experimental cattle infections and four had camel/goat (rare form) patterns.     

Streptococcal protein G-gold complex: comparison with staphylococcal protein A-gold complex for spot blotting and immunolabeling

Protein G, a cell wall protein isolated from human group G streptococci strain G148, binds in a similar manner as protein A from Staphylococcus aureus to the Fc portion of IgG molecules. Indeed, protein G has been proposed as a superior Fc binding protein due to its broader species reactivity. Thus, we have prepared a complex of protein G with particles of colloidal gold and determined its applicability for spot-blot analysis and postembedding immunolabeling by comparing it with protein A-gold complex. By spot-blot analysis no difference in binding of protein G-gold or protein A-gold to IgG molecules from a whole spectrum of animal species was observed. Moreover, using rabbit, sheep, or goat anti-rat albumin antibodies to detect nitrocellulose-immobilized rat albumin or antigenic sites in paraffin and Lowicryl K4M thin sections from rat liver, no difference was found with protein G-gold or protein A-gold. Similarly, no difference in binding to protein G-gold or protein A-gold was observed with a battery of monoclonal antibodies. However, in contrast to expectations, protein A-gold reacted well with both sheep and goat IgG molecules; indeed, for the light and electron microscopic localization of albumin with sheep or goat antibodies it was as efficient as protein G-gold. These results demonstrate, therefore, that both protein G-gold and protein A-gold are useful second step reagents for immunolabeling and that protein G-gold was not a superior probe in the systems tested.