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Biomedical subjects

H Ohnuma

Publications and source records attributed to H Ohnuma.

At least 73 records · Page 4Linked to original sources
PubMed1987

A synthetic peptide coded for by the pre-S2 region of hepatitis B virus for adding immunogenicity to small spherical particles made of the product of the S gene.

Small spherical particles produced in the non-permissive phase of hepatitis B virus infection, when the viral genome is integrated into the chromosome of hosts, are rich in the product of the S gene, but poor in the product of the pre-S2 region. For the purpose of adding immunogenicity to spherical particles deficient in the pre-S2 region product, they were conjugated with a synthetic peptide of 19 amino acid residues. The peptide reproduced a hydrophilic area of the pre-S2 region product encoded by viral genomes of subtypes adr, ayw and ayr. The spherical particles supplemented with the pre-S2 peptide raised antibody to the pre-S2 region product in mice, in addition to antibody to the product of the S gene. Antibody to pre-S2 region product, prepared from sera of immunized mice by absorption with the S gene product, bound to spherical particles bearing pre-S2 region product, irrespective of adr, adw, ayw or ayr subtype, and agglutinated hepatitis B virions in immune electron microscopy. Based on the results obtained, the synthetic peptide may prove useful in adding protective efficacy to small spherical particles poor in pre-S2 region product.

Absorption↗
PubMed1986

A solid-phase enzyme immunoassay for the determination of IgM and IgG antibodies against translation products of pre-S1 and pre-S2 regions of hepatitis B virus.

The envelope of hepatitis B virus is coded for by pre-S1, pre-S2 regions and the S gene. A method was developed to determine antibody to the product of pre-S1 region (anti-pre-S1) and antibody to the product of pre-S2 region (anti-pre-S2), either of IgM or IgG class, by a solid-phase enzyme immunoassay. For the determination of anti-pre-S1, tubular particles containing translation products of pre-S1, pre-S2 regions and the S gene were broken into constituent envelope polypeptides and immobilized on a solid support. Serums were absorbed with spherical particles containing translation products of pre-S2 region and the S gene, obtained from plasma positive for hepatitis B e antigen (HBeAg) and deprived of particles carrying pre-S1 product by an affinity column. They were then tested for the binding with tubular polypeptides fixed on a solid support, and the bound antibody representing anti-pre-S1 was detected by monoclonal antibody to human IgM/mu or IgG/gamma labeled with horseradish peroxidase. For the determination of anti-pre-S2, test serums were absorbed with spherical particles containing the product of the S gene, obtained from plasma positive for antibody to HBeAg and deprived of particles bearing pre-S2 product by an affinity column. They were then tested for the binding with polypeptides, fixed on a solid support, composed of products of pre-S2 region and the S gene. The assay was applied to the determination of anti-pre-S1 and anti-pre-S2 of IgM or IgG class in asymptomatic carriers and in persons who had recovered from infection with hepatitis B virus.

Antibodies, Monoclonal↗
PubMed1986

Polypeptides coded for by the region pre-S and gene S of hepatitis B virus DNA with the receptor for polymerized human serum albumin: expression on hepatitis B particles produced in the HBeAg or anti-HBe phase of hepatitis B virus infection.

There are four polypeptides coded for by the region Pre-S and gene S on DNA of hepatitis B virus that carry the receptor for polymerized human serum albumin (poly-HSA), i.e., P31 and P39, as well as their glycosylated counterparts P35 and P43. With the use of monoclonal antibodies directed to Pre-S(1) sequence and Pre-S(2) sequence (bearing the receptor for poly-HSA), the content of these polypeptides, as well as their expression on the surface, was determined for hepatitis B particles of various categories. P39 and P43, carrying both Pre-S(1) and Pre-S(2) sequences, were contained abundantly in Dane and tubular particles, and to a much lesser extent in small spherical particles, all of which were purified from plasma containing hepatitis B e antigen (HBeAg). P31 and P35, carrying Pre-S(2) but not Pre-S(1) sequence, were contained comparably in these three categories of hepatitis B particles. In remarkable contrast, small spherical particles derived from plasma containing antibody to HBeAg were very low in the content of any Pre-S polypeptides. P31 and P39 showed higher activities for poly-HSA receptor than their glycosylated versions. When Dane particles were digested with trypsin, the poly-HSA receptor was deprived in parallel with the loss of antigenicity for Pre-S(2) sequence. The antigenicity for Pre-S(1) sequence was much less affected, and that for the product of gene S was virtually unchanged by the digestion.

Amino Acid Sequence↗
PubMed1986

Large hepatitis B surface antigen polypeptides of Dane particles with the receptor for polymerized human serum albumin.

Large hepatitis B surface antigen polypeptides with apparent molecular sizes of 39,000 and 43,000 daltons (P39 and P43) were liberated from a purified preparation of Dane particles of subtype adr. They were tested for reactivity with monoclonal antibodies raised against three synthetic oligopeptides representing fundamental sequences of the pre-S region in deoxyribonucleic acid of hepatitis B virus (subtype adr), as well as with monoclonal antibody against the major surface antigen polypeptide (P22) coded for by the S gene. Both P39 and its glycosylated form P43 bound to all four monoclonal antibodies, thereby indicating that they were coded for by the sequence of 1200 nucleotides, from the second ATG codon in the pre-S region to the stop codon of the S gene. Both P39 and P43 bound to polymerized human and chimpanzee albumins, but not to polymerized albumin from species without susceptibility to hepatitis B virus. Due to their presence in Dane particles and the expression of a polyalbumin receptor, the immune responses against P39 and P43 may have significance in infection with hepatitis B virus and its immunoprophylaxis.

Antibodies, Monoclonal↗
PubMed1986

A synthetic peptide vaccine involving the product of the pre-S(2) region of hepatitis B virus DNA: protective efficacy in chimpanzees.

The S gene encoding the major surface polypeptide of hepatitis B virus is preceded by the region pre-S(2) with a capacity to code for 55 amino acid residues. In the product of region pre-S(2), the sequence of 19 amino acid residues (amino acids 14-32 from the N terminus) representing an area of high local hydrophilicity is shared by viral strains of subtypes adr, ayw, and ayr; residue 22, phenylalanine, is replaced by leucine in a strain of the other subtype, adw. A synthetic peptide vaccine involving these 19 amino acid residues, when given to two chimpanzees, raised antibodies that bound to viral particles and protected the animals from challenge with 10(6) chimpanzee infectious doses of hepatitis B virus.

Animals↗
PubMed1986

Translation products of pre-S(1), pre-S(2) regions and the S gene of hepatitis B virus: susceptibility of their antigenic activities to treatment with heat, urea, formalin or pepsin.

Hepatitis B subviral particles, purified from plasma of asymptomatic carriers seropositive for hepatitis B e antigen, were treated with various conditions reported for the processing of vaccines. Thereafter, antigenic activities displayed by the translation products of pre-S(1), pre-(2) regions and the S gene were determined with monoclonal antibodies, and the reactivity for polyalbumin receptor was tested. Heating at 100 degrees C for 1.5 min and then at 65 degrees C for 10 h preserved more than 1/2 of antigenic activities representing products of pre-S(1), pre-S(2) regions and the S gene. After incubation in the presence of 8 M urea at 37 degrees C for 4 h, more than 2/3 of antigenic activities still remained. The antigenic activity of the S gene product was decreased to 2/3 and that of pre-S(2) region product to 1/3, after treatment with formalin at the final concentration of 1:4000 at 37 degrees C for 72 h, whereas the activity of pre-S(1) region product was affected drastically. Although 1/5 of the antigenic activity of the S gene product survived the digestion with pepsin for 18 h, antigenic activities of pre-S(1) and pre-S(2) region products were destroyed almost completely. Polyalbumin receptor, borne by the pre-S(2) region product, was lost by pepsin digestion also. Based on the results obtained, heating may be most appropriate for sterilizing plasma-derived hepatitis B particles for use as a vaccine, because it is reliably virucidal and would not affect the protective efficacy to an extent as the other virucidal methods would.

Epitopes↗
PubMed1984

A polypeptide containing 55 amino acid residues coded by the pre-S region of hepatitis B virus deoxyribonucleic acid bears the receptor for polymerized human as well as chimpanzee albumins.

The receptor for polymerized human and chimpanzee albumins has been identified on a hepatitis B surface antigen polypeptide of approximately 31,000 daltons. The polypeptide, designated P31, is composed of the major polypeptide of hepatitis B surface antigen (P22) and an additional, as yet unidentified, amino acid sequence. We split P31 with cyanogen bromide and obtained a polypeptide of approximately 8000 daltons (P8) that contained carbohydrate. P8 could bind to polymerized human and chimpanzee albumins, but not to polymerized albumins from animals without susceptibility to hepatitis B virus. The amino acid composition of P8 closely resembled that of 55 amino-acid sequence coded by the pre-S region in the deoxyribonucleic acid of hepatitis B virus. Using monoclonal antibody against P8, a solid-phase sandwich radioimmunoassay was developed for the specific determination of hepatitis B surface antigen bearing the receptor for polymerized albumin in the serum of patients with hepatitis B virus infection.

Amino Acid Sequence↗
PubMed1983

A hepatitis B surface antigen polypeptide (P31) with the receptor for polymerized human as well as chimpanzee albumins.

Hepatitis B virus, and hepatitis B surface antigen particles co-occurring with hepatitis B e antigen, have the receptor for polymerized human and chimpanzee albumins that may be involved in the hepatotropism of hepatitis B virus. We identified the receptor on a hepatitis B surface antigen polypeptide with a molecular size of 31,000 daltons (P31). P31 bound to polymerized albumins from human and chimpanzee, but did not react with polymerized albumins from the experimental animals without susceptibility to hepatitis B virus. P31 was composed of the major polypeptide of hepatitis B surface antigen with a molecular size of approximately 22,000 daltons (P22) and additional 55 amino acid residues coded by the pre-S region in the hepatitis B virus-specific deoxyribonucleic acid. Because P22 did not react with polymerized albumin, the sequence of 55 amino acid residues in the pre-S region appeared to bear the receptor. Polypeptides with the receptor for polymerized albumin may make an efficacious hepatitis B vaccine, because they could raise antibodies against the putative site on hepatitis B virus capable of binding with hepatocytes to initiate the infection.

Amino Acids↗
PubMed1982

A glycopeptide containing 15 amino acid residues derived from hepatitis B surface antigen particles: demonstration of immunogenicity to raise anti-HBs in mice.

The major polypeptides composing hepatitis B surface antigen (HBsAg) particles are P-I and P-II. P-II shares the same amino acid sequence as P-I and contains an additional carbohydrate moiety of mol. wt approximately 5000. When a purified preparation of P-II was digested with Nagarse and then with Pronase P, it gave rise to a glycopeptide containing 15 amino acid residues and the carbohydrate moiety of P-II. The N-terminal amino acid sequence of the glycopeptide was determined to be Lys-Pro-Thr-Asp-Gly-Asn-. The polysaccharide moiety contained 5 moles of N-acetylglucosamine and was connected with Asn at the sixth position from the N-terminus. When mice were immunized against this HBsAg glycopeptide, they raised humoral antibodies which bound to each of three preparations of P-I derived from HGsAg particles of subtypes adw, adr and ayw, thereby indicating that the sequence of 15 amino acids in the glycopeptide would constitute a common antigenic structure of HBsAg.

Amino Acid Sequence↗
PubMed1979

Absorption, fluorescence, and linear dichroism spectra of fluorescein mercuric acetate (FMA) bound to F-actin. Two kinds of effects of divalent cations.

Two kinds of F-actin were prepared; one binds magnesium at the unique divalent cation binding site of actin protomer and the other binds calcium at this site. They were designated as F(Mg)-actin and F(Ca)-actin, respectively. The binding of fluorescein mercuric acetate (FMA) to F(Mg)-actin and F(Ca)-actin was studied spectroscopically. The absorption and fluorescence spectra of bound FMA differed slightly but distinctly between F(Mg)-actin and F(Ca)-actin. Moreover, FMA bound to F(Mg)-actin showed linear dichroism in the presence of 2 mM MgCl2 (or 2mM CaCl2) in the solvent, while the dichroism was abolished by the removal of divalent cations from the solvent. In contrast, FMA bound to F(Ca)-actin did not show any appreciable linear dichroism irrespective of the presence (or absence) of divalent cations in the solvent. These results suggest that the structure of F-actin is characteristically regulated by divalent cations in a dual mode.

Actins↗
PubMed1976

Fluorescence study of N-(3-pyrene)maleimide conjugated to rabbit skeletal F-actin and plasmodium actin polymers.

A fluorescent probe N-(3-pyrene)maleimide was conjugated to rabbit skeletal F-actin at the site of most reactive sulfhydryl group (Cys-373). Its fluorescence anisotropy decay showed a single correlation time of 560 ns at 25 degrees C, which is in a very good agreement with the correlation time of the dansyl-L-cysteine group conjugated to the same site of F-actin reported very recently [Wahl, Ph., Mihashi, K, and Auchet, J-C. (1975) FEBS Lett. 8, 164-167]. Actin from plasmodia of myxomycates, Physarum polycepharum, was also conjugated with N-(3-pyrene) maleimide and the fluorescence anisotropy was compared with rabbit skeletal F-actin using the classical steady excitation method. It was found that the internal mobility of the magnesium polymer of plasmodium actin is remarkably larger than both plasmodium F-actin and rabbit skeletal F-actin.

Actins↗