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PubMed1984

Distribution of haptoglobins in different dialect groups of Chinese, Malays and Indians in Singapore.

A total of 870 subjects comprising 524 Chinese (from different dialect groups), 231 Malays and 115 Tamil Indians were investigated for the distribution of haptoglobin types and ABO blood groups. Haptoglobins were typed by PAG electrophoresis using discontinuous buffer system. The frequencies of Hp,1 Hp2 and Hp0 were found to be 0.330, 0.670 and 0.029 in Chinese; 0.298, 0.702 and 0.004 in Malays; and 0.167, 0.833 and 0.009 in Indians. The Hainanese had the highest frequency of Hp1 (0.375) followed by Cantonese (0.348), Teochew (0.333) and Hakkas (0.288). The distribution of all the phenotypes of haptoglobin was at equilibrium in all the population groups studied. No association of ABO blood groups was detected with the haptoglobin types. However, there was an excess of AB blood group in persons carrying Hp2 compared with those with Hp1.

ABO Blood-Group System↗
PubMed1980

Antistreptococcal antibodies, rheumatoid factors and haptoglobin in apes and monkeys.

Sera of 157 baboons (Papio hamadryas and P. anubis) 21 chimpanzees (Pan troglodytes) five orang utans (Pongo pygmaeus) three mountain gorillas (Gorilla gorilla beringei) and three gibbons (Hylobates lar lar) were examined for the content of antistreptolysin O, antidesoxyribonuclease B, for the presence of rheumatoid factors as well as for the level and type of haptoglobin. The mean antistreptolysin O titer (AST) in baboons was 106 ASU +/- 18 in dextransulfate absorbed sera ("real" AST) and 182 ASU +/- 34 in non-absorbed sera. The mean decrease after absorption was 20% (i.e., 20% inhibitor + 80% antistreptolysin O), a value that is lower than previously found in rhesus monkeys (55%) or in man (40%). Raised values of anti-DNase B were found in two baboons only, and none of the sera of that species displayed presence of rheumatoid factors. In chimpanzees, the mean AST was 68 +/- 29 in absorbed and 87 ASU +/- 57 in non-absorbed sera. Anti-DNase B was raised in three animals, and in two cases the increase was correlated with raised AST. Of 19 chimpanzee sera examined, 13 were found to contain antigammaglobulins ("rheumatoid factors") the titers of which reached 1:64 or more. All primate sera tested so far showed haptoglobin type 1-1 or Hp 1-1-like patterns. The haptoglobin level in chimpanzees and baboons was comparable to that established in man; in rhesus monkey, on the other hand, much lower values (40-62 mg/100 ml) or ahaptoglobinemia were observed. The sera of all monkeys and apes tested so far showed a very low (undiluted, or up to 1:10 titer at most) agglutinating activity against T4-antigen-carrying streptococci. This is in agreement with our observations made previously which indicated that human or animal sera of haptoglobin type 1-1 agglutinated streptococci to a much lower degree than type Hp 2-2 or type Hp 2-1 sera.

Animals↗
PubMed1981

Haptoglobin. A novel mode of biosynthesis of a liver secretory glycoprotein.

The de novo biosynthesis of the heterotetrameric (alpha 2 beta 2) serum glycoprotein, haptoglobin, was studied using a rabbit reticulocyte cell-free translation system and mRNA preparations from the livers of turpentine-treated rats. Analysis of the translation mixtures with either antisera specific for the alpha-subunit (anti-alpha-IgG) or the beta-subunit (anti-beta-IgG) or the native haptoglobin tetramer (anti-alpha 2 beta 2-IgG) resulted in each instance in the recovery of a single protein exhibiting a Mr = approximately 38,000. Cleavage of the translation product with cyanogen bromide or trypsin resulted in the generation of small peptide fragments that were specifically immunoadsorbed with either anti-alpha-IgG or anti-beta-IgG. These results indicated that the primary translation product of haptoglobin mRNA is a single polypeptide that contains the elements of both the alpha-subunit and the beta-subunit of the protein. Presumably haptoglobin is synthesized in vitro as a single precursor protein that is proteolytically processed post-translationally to form the dissimilar alpha- and beta-subunits of the native protein.

Animals↗
PubMed1977

[Relationships between Streptococcus pyogenes T4-antigens and haptoglobin types (author's transl)].

Some strains of beta-haemolytic streptococci were agglutinated with high titers (1:200-1:6400) by human sera of the haptoglobin types 2-2 and 2-1. No agglutination or with low titers (up to 1:20) was observed with sera of the haptoglobin type 1-1. This reactivity depends from the contents of Streptococcus pyogenes T-antigens of the T-complex 4,24... This T4-antigen is present in group A streptococci (Strep. pyogenes) of the types 4, 24, 26, 28, 29, 46, 48 and 60 but it may be present also in some strains of streptococcal groups C and G. During a 10-year period we isolated 12 strains of Strep. equisimilis (group C) carrying the T-4 antigen (1.6%) and 50 group-G streptococci with T-4 antigen (6.4%) of all group G streptococci). These strains were agglutinated without an exception with high titers by Hp 2-2 and Hp 2-1 sera but not by sera of the haptoglobin type 1-1. The same particuliarity was shown by Streptococcus pyogenes types of the T-complex 4, 24... One strain of type 26 (BC 179) has no T antigen and therefore it was not agglutinated in the above mentioned manner. The phenomenon depends from the medium; it occurs after cultivation of the streptococci in Pope broth or in meat-infusion with glucose but not or only reduced in beef heart-proteose-medium. The agglutination reaction is caused by the haptoglobin but not by agglutinins against the T4-antigens.

Agglutination↗
PubMed1995

Biliary haptoglobin, a potent promoter of cholesterol crystallization at physiological concentrations.

BACKGROUND/AIMS: Several proteins present in human bile have been reported to promote cholesterol crystallization and thus are potentially important in the formation of cholesterol crystals as the initial stage in gallstone pathogenesis. To be physiologically relevant, such proteins must either be present in high concentration in bile or have a potent promoting activity. The current study explored several of the more abundant but unexamined biliary proteins based upon their also having sufficiently high serum concentrations that antibodies were available for both their isolation and quantitation. METHODS: Protein purification was accomplished by immunoaffinity chromatography of bile followed by delipidation. Con A affinity chromatography of bile was used to obtain the bound fraction, a portion of which was delipidated. Crystallization-promoting activity of both the purified proteins and Con A-bound glycoprotein fractions (CABG) was measured by a photometric crystal growth assay. A competitive antibody-capture ELISA assay was developed to measure concentrations of alpha 1-antitrypsin, transferrin, and haptoglobin in native bile. RESULTS: At their relevant physiological concentrations, biliary haptoglobin (15 micrograms/ml) had a crystallization-promoting activity twice that of the biliary IgM (75 micrograms/ml) used as a reference standard (P < 0.05). Biliary transferrin (20 micrograms/ml) had only modest promoting activity (P < 0.05). Biliary alpha 1-antitrypsin (50 micrograms/ml), by contrast, showed no promoting activity. Delipidation of the CABG fraction decreased its promoting activity by 75%. Biliary haptoglobin accounts for about 30% of delipidated total CABG-promoting activity. CONCLUSIONS: Biliary haptoglobin at its physiological concentration has a highly potent crystallization-promoting activity and thus becomes a candidate for major attention in understanding gallstone pathogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody Specificity↗
PubMed1994

[Renal tubular dysfunction in open pediatric heart surgery--preventive effect of haptoglobin].

Preventive effect of haptoglobin (Hb) for renal tubular dysfunction was studied in 16 pediatric patients undergoing open heart surgery under extracorporeal circulation (ECC). The patients were divided into two groups; Hp(+) group consisting of 7 patients administered haptoglobin (100 U/kg) in priming of ECC, and Hp(-) group of 9 patients not administered haptoglobin. As parameters of renal tubular function, urinary alpha 1-microglobulin-index (U-alpha 1m.I), urinary beta 2-microglobulin-index (U-beta 2m.I), urinary N-acetyl-beta-D-glucosaminidase-index (U-NAG.I), fractional clearance of alpha 1m (Fc-alpha 1m) and beta 2m (Fc-beta 2m), as well as Free-Hb, were measured just before start of ECC and then at periodical time after ECC to the 7th day. The results obtained are as follows. (1) Maximum Free-Hb in Hp(+) group was significantly less (p < 0.05) than that in Hp(-) group. (2) Every parameter of renal tubular function were shown a peak at the end of ECC. Maximum values of U-alpha 1m.I, U-NAG.I and Fc-alpha 1m in Hp(+) group were significantly less (p < 0.05) than those in Hp(-) group. Maximum U-beta 2m.I and Fc-beta 2m in Hp(+) group were less than those in Hp(-) group, although there was no significant difference. These results indicate that administration of haptoglobin suppresses the increase of Free-Hb and is useful for prevention of renal tubular dysfunction during ECC.

Acute Kidney Injury↗
PubMed1993

Immunoaffinity purification of human haptoglobin using monoclonal antibodies.

Two monoclonal antibodies, coupled to Sepharose 4B, were used for rapid isolation of the human haptoglobin in a single chromatographic step. The purity of haptoglobin was judged by SDS polyacrylamide gel electrophoresis, immunoblotting, immunoelectrophoresis and size exclusion high performance liquid chromatography. Moreover, the preparation showed ability to form active complexes with hemoglobin, Concanavalin A and specific antibody. Polyclonal goat antiserum produced with the obtained haptoglobin preparation formed one precipitin line with whole human serum. On the other hand, monoclonal antibodies can be purified by means of haptoglobin coupled to matrix.

Animals↗
PubMed1975

[An immunonephelometric determination of rabbit haptoglobin].

An immunonephelemetric determination of rabbit haptoglobin was carried out. At first, pure haptoglobin was isolated and then monospecific immunserums were obtained from rats. This method completes the regular determination of haptoglobin in all cases where the peroxydasic activity of the haptoglobin-hemoglobin complex is inhibited either by an hemolytic process, as is the case for rabbits, or by some inhibitors of the peroxydasic reaction.

Animals↗
PubMed1993

A base substitution in the promoter associated with the human haptoglobin 2-1 modified phenotype decreases transcriptional activity and responsiveness to interleukin-6 in human hepatoma cells.

An A-to-C base substitution at nucleotide position -61 in the promoter region of the human haptoglobin gene (Hp) has been shown to be strongly associated with the haptoglobin 2-1 modified (Hp2-1mod) phenotype. In order to investigate whether this base substitution is the cause of reduced expression of the Hp2 allele relative to the Hp1 allele in individuals with the Hp2-1mod phenotype, we used the chloramphenicol acetyl transferase (CAT) expression system to evaluate promoter function. In HepG2 cells, which normally express their endogenous haptoglobin genes, CAT plasmid constructs with the -61C base change in the promoter had about 10-fold-lower transcriptional activity after transfection than did the Hp control construct. The -61C substitution also rendered the construct unresponsive to treatment by interleukin-6 after transfection into Hep3B2 cells, which normally do not express haptoglobin but do so in response to stimulation by acute-phase reactants. In addition, two base substitutions, T to A and A to G, at positions -104 and -55G, respectively, in the promoter region of the Hp1 allele, are also associated with the Hp2-1mod phenotype. CAT constructs with both substitutions (-104A-55G) and with one substitution (-55G) showed activity similar to that in the Hp control when transfected into both HepG2 and Hep3B2 cells, although interleukin-6 induction was less than with the Hp control construct. These results further support the hypothesis that the Hp2-1mod phenotype results, in part, from the -61C mutation in the promoter region of the Hp2 gene.

Alleles↗
PubMed1996

Serum haptoglobin suppresses T-lymphocyte functions following burns.

It is well known that serum immunosuppressive factors play an important role in the mechanism of postburn immunosuppression. This study was intended to investigate the effect of haptoglobin, purified from the serum of burned patients by affinity chromatography, on the proliferation and interleukin-2 (IL-2) secretion of normal murine thymocytes induced by ConA and the proliferation of IL-2 dependent cell line (CTLL-2) stimulated by recombinant human IL-2, so as to elucidate the role of serum haptoglobin in postburn T-lymphocyte dysfunction. The results showed that purified haptoglobin, at the level equivalent to the concentration found in serum of burned patients, significantly inhibited the proliferation and IL-2 secretion of normal murine thymocytes as well as CTLL-2 proliferation; whereas it exhibited no immunosuppressive effects at the level equivalent to the concentration found in serum of normal volunteers. According to the results reported here, it is suggested that extraordinary increase in serum haptoglobin level may be an important factor of impaired T-lymphocyte responses following burns.

Animals↗
PubMedDate not supplied

[The effect of thyroid hormones on changes in the haptoglobin and transferrin levels in rats].

The author presents data concerning the experimental parallel study on male albino rats (171) of the effect of various thyroid hormones on the haptoglobin and transferrin level in the blood serum. On the basis of the data obtained a study was made of the correlation between the changes in the content of iodine-bound protein (IBP) and the mentioned blood glycoproteins in the experimental animals. There was revealed an influence of the thyroid gland on the content and the character of the changes in the haptoglobin and transferrin concentration in the blood serum. Within the range of physiological action thyroid hormones increased the level of blood component data, and in toxic doses--decreased it. The changes in the content of blood glycoproteins depended on the hormone, dosage and the duration of its administration. Between the changes in the concentration of IBP, haptoglobin and transferrin there proved to be a correlation in all the experimental groups with L-thyroxin and triiodthyronin toxicosis. Normalization of the haptoglobin and transferrin level occurred in the majority of the hyperthyroid animals 12 to 24 days after the end of the experiment.

Animals↗
PubMed1989

Elevated plasma levels of haptoglobin in Duchenne muscular dystrophy:electrophoretic variants in patients with a severe form of the disease.

Analysis of plasma proteins of Duchenne muscular dystrophy (DMD) patients and normal age-matched boys using two dimensional gel electrophoresis and densitometry indicated a three-fold increase in the average haptoglobin level in DMD plasma. Two electrophoretic variants of haptoglobin in which the alpha 2 chain had more basic or more acidic spots were found in DMD patients with a rapidly progressing form of the disease. The basic variant was present in relatively low amount. Possible reasons for the elevated haptoglobin levels are discussed.

Child, Preschool↗
PubMed1985

Structure and expression of the human haptoglobin locus.

Human genomic clones of the haptoglobin Hp1F and the "haptoglobin related' gene (Hpr) have been isolated. The two genes are adjacent, spanning a region of approximately 21 kb. A comparison of their coding sequences shows that Hpr differs from Hp1F at 28 codons. Northern blot and primer elongation analyses with human liver RNA show that the haptoglobin gene Hp1F appears to be transcribed some 1000-fold less in fetal than in adult liver. In adult liver the amount of Hpr mRNA is at the lower limit of detection, therefore the extent of its expression is at most less than 1000-fold that of the Hp1F gene. No Hpr mRNA can be detected in fetal liver.

Base Sequence↗
PubMed1989

The human haptoglobin gene promoter: interleukin-6-responsive elements interact with a DNA-binding protein induced by interleukin-6.

Transcription of the human haptoglobin (Hp) gene is induced by interleukin-6 (IL-6) in the human hepatoma cell line Hep3B. Cis-acting elements responsible for this response are localized within the first 186 bp of the 5'-flanking region. Site-specific mutants of the Hp promoter fused to the chloramphenicol acetyl transferase (CAT) gene were analysed by transient transfection into uninduced and IL-6-treated Hep3B cells. We identified three regions, A, B and C, defined by mutation, which are important for the IL-6 response. Band shift experiments using nuclear extracts from untreated or IL-6-treated cells revealed the presence of IL-6-inducible DNA binding activities when DNA fragments containing the A or the C sequences were used. Competition experiments showed that both sequences bind to the same nuclear factors. Polymers of oligonucleotides containing either the A or the C regions confer IL-6 responsiveness to a truncated SV40 promoter. The B region forms several complexes with specific DNA-binding proteins different from those which bind to the A and C region. The B region complexes are identical in nuclear extracts from IL-6-treated and untreated cells. While important for IL-6 induction in the context of the haptoglobin promoter, the B site does not confer IL-6 inducibility to the SV40 promoter. Our results indicate that the IL-6 response of the haptoglobin promoter is dependent on the presence of multiple, partly redundant, cis-acting elements.

Base Sequence↗
PubMed1995

A human (3.3 kb) haptoglobin-CAT transgene is modulated in lungs of transgenic mice by inflammation.

Four independent lines of transgenic mice were produced carrying integrated copies of a chimeric gene composed of 3.3 kb of the human haptoglobin 5' regulatory region fused to the CAT (chloramphenicol acetyl transferase) reporter gene. Although the endogenous mouse haptoglobin (Hp) and human haptoglobin (HP) genes express mainly in liver and lung, expression of the human 3.3-kb HP-CAT transgene was not detected until after induction of inflammation and then only in lungs. The results indicated that the transgene maintained the regulatory DNA elements required for lung specific responsiveness to inflammation in vivo but lacked the DNA sequence required for robust expression in liver. The DNA sequence(s) responsible for the normally high level of HP expression in liver either reside outside the 3.3-kb regulatory region of the HP chimeric gene or this region contains a suppressor sequence affecting tissue specific expression in the liver.

Animals↗
PubMed1996

Properties of nuclear matrix proteins that bind the 5' flanking region of the haptoglobin gene are changed during the acute-phase response.

It was previously shown that during the acute-phase response-induced elevated transcription of the rat haptoglobin gene, protein p55 and the lamins mediate the increased binding of restriction fragment II (-541/-146) via a 38 bp adenine tract lying 147 bp upstream from the haptoglobin gene cis element (-165/-56), to scaffold type II-like nuclear matrices. Here we show that the fragment II binding pattern to > or = 40 kDa proteins of nuclear matrices analogous to type I scaffolds is more complex. Fragment II bound conspicuously to a 40 and less so to p55, a 60 kDa protein and the lamins of control matrices. During increased gene transcription, it bound prominently to p55, the lamins, and less so to 45 and 52 kDa proteins. This was accompanied by the tenacious binding of the DNA to isolated nuclear matrices in vitro and post-translational modifications of certain matrix proteins. The lamins and p55 demonstrated a greater N-acetylglucosamine/sialic acid content and p55 an increased in vitro phosphorylation by a nuclear matrix-associated cyclic-nucleotide-independent kinase. The acute-phase response also caused an increased partitioning of p55 with the nuclear matrix. It was concluded that, as a result of a molecular remodelling of the nuclear matrix at the point of contact with chromatin, the nature of its association with region II DNA changed during elevated haptoglobin gene expression.

Acute-Phase Reaction↗
PubMedDate not supplied

Secretion of glycosylated human recombinant haptoglobin in baculovirus-infected insect cells.

Human haptoglobin (Hp alpha 2 beta) was synthesized in insect cells using the baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV) as an expression vector. Viruses carrying the proHp alpha 2 beta cDNA, either fused or non fused to viral polyhedrin DNA sequences, expressed intracellularly low levels of unglycosylated and non maturated haptoglobin. On the contrary, recombinant viruses containing the preproHp alpha 2 beta cDNA directed the expression of high levels of prohaptoglobin. To a large extent, the uncleaved product was found in the culture medium as a glycosylated molecule. Despite the lack of maturation into subunits, the secreted recombinant prohaptoglobin was able to bind hemoglobin in vitro, although less efficiently than plasma-derived haptoglobin.

Amino Acid Sequence↗
PubMed1980

Prevention of hemoglobinuria by administration of haptoglobin.

This report describes the role of haptoglobin in preventing hemoglobinuria. In rabbits, human haptoglobin administered i.v. worked preventively against the development of hemoglobinuria in spite of the presence of a large amount of hemolysate containing free hemoglobin. More specifically: (1) the kidney did not present a dark brown color, (2) the deposition of iron in the kidney was significantly less than that in the same organ of rabbits given hemolysate only, and (3) the microangiographic and histological findings of the kidney were close to normal patterns. From the above it may be concluded that the administration of haptoglobin is effective for the prevention of hemoglobinuria and subsequent renal damage.

Angiography↗