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Biomedical subjects

M Mayumi

Publications and source records attributed to M Mayumi.

At least 307 records · Page 17Linked to original sources
PubMed1980

Hepatitis B e antigen polypeptides isolated from sera of individuals infected with hepatitis B virus: comparison with HBeAg polypeptide derived from Dane particles.

Hepatitis B e antigen (HBeAg) occurs in the serum of individuals infected with hepatitis B virus both free and in association with IgG. Utilizing a succession of steps involving salt precipitation, affinity chromatography, ion-exchange chromatography and isoelectrofocusing, we isolated free and IgG-bound forms of HBeAg from the sera of infected individuals with an overall gain in specific activity of 3000-fold and 540-fold, respectively. Polypeptide profiles of purified HBeAg preparations were studied by SDS-polyacrylamide gel electrophoresis in the presence of 2-mercaptoethanol. Both free and IgG-bound preparations revealed polypeptides with mol. wt. of 15500 (P15.5) and 16 500 (P16.5), and HBeAg activity was detected corresponding to their positions. The HBeAg polypeptides (P15.5/16.5) derived from sera were physicochemically different from the two polypeptides with HBeAg activity (P19 and P45) liberated from Dane particle cores by the conventional method involving incubation with Nonidet P40 and 2-mercaptoethanol. However, when core particles were prepared in the presence of a proteolytic enzyme, in addition to Nonidet P40 and 2-mercaptoethanol, they gave rise to HBeAg polypeptides with mol. wt. of 31000 (P31) and 15 500. Furthermore, P31 split into P15.5 when heated at 100 degrees C for 2 min. On the basis of these results, P15.5 may be assumed to be the essential polypeptide bearing HBeAg activity in the serum and also in Dane particles.

Hepatitis B↗
PubMed1980

Isolation of Dane particles containing a DNA strand by metrizamide density gradient.

Dane-particle cores labelled with [3H]TTP were subjected to ultracentrifugation in a metrizamide density gradient. Two populations of core particles with different densities were obtained, and radioactivity was found only in the cores that sedimented at the lower density (1.19-1.23 g/cm3). All the cores in this group, when spread in a monolayer, were found to expel a closed circular double-stranded DNA molecule. In contrast, the core particles that sedimented at the higher density (1.23-1.27 g/cm3) were not associated with radioactivity, nor was any DNA strand extruded from them. These results show that metrizamide density gradients allow the separation of complete hepatitis B virions for the study of viral DNA.

Centrifugation, Density Gradient↗
PubMed1980

A 49,000-dalton polypeptide bearing all antigenic determinants and full immunogenicity of 22-nm hepatitis B surface antigen particles.

Spherical 22-nm hepatitis B surface antigen (HBsAg) particles with a subtype adr were purified from plasma of asymptomatic carriers of hepatitis B virus. When purified HBsAg preparation was treated with sodium dodecylsulfate in the absence of reducing agents, it yielded spherical particles with a diameter smaller than 22 nm, and in addition, a polypeptide with a molecular size of 49,000 daltons, which seemed to constitute the outer coat of HBsAg particles. The recovery of the polypeptide on the basis of optical density at 280 nm was 2%, starting from 22-nm HBsAg particles. The 49,000-dalton polypeptide apparently represented a structural unit of the surface of HBsAg particles, since it bore all common (a, Re) and subtypic (d, r) determinants with essentially the same antigenic titers as intact HBsAg particles. Furthermore, this polypeptide was equally immunogenic as 22-nm HBsAg particles in raising corresponding antibodies in mice. When the 49,000-dalton polypeptide was reduced in the presence of 2-mercaptoethanol, it cleaved into 22,000- and 27,000-dalton polypeptides with a drastic decrease in both antigenicity and immunogenicity. These results indicate the different molecular arrangements between outer coat and inner portion of HBsAg particles, and a potential application of the 49,000-dalton polypeptide as a component vaccine, owing to its strong antigenicity both in vitro and in vivo.

Animals↗
PubMed1980

Viruslike particles in a plasma fraction (fibrinogen) and in the circulation of apparently healthy blood donors capable of inducing non-A/non-B hepatitis in humans and chimpanzees.

Two patients who had received a fibrinogen preparation contracted hepatitis of non-A/non-B etiology 3 and 8 wk after the injection. A chimpanzee inoculated with the same preparation developed hepatitis 11 wk later, with an increase in SGPT and a liver pathology compatible with acute viral hepatitis. His preacute serum containing the presumptive etiologic agent induced hepatitis in another chimpanzee. Electron microscopic observation of the liver of these chimpanzees biopsied during preacute and acute stages revealed peculiar tubular structures composed of two unit membranes with electron-opaque material in between. Using the serum obtained from infected chimpanzees at convalescence as an antibody reagent, viruslike particles were identified in the fibrinogen preparation by immune electron microscopy. When the serum of 100 apparently healthy blood donors with SGPT value of 80 Karmen units/ml or higher was tested for viruslike particles, eight were found to be positive. Furthermore, one of these sera, when a 5-ml amount was injected into each of two chimpanzees, induced hepatitis with viruslike particles in the circulation and characteristic tubular changes in the liver. On the basis of the results obtained, the viruslike particles in the fibrinogen preparation, as well as in the circulation of apparently healthy donors, were capable of inducing hepatitis of non-A/non-B category with a liver pathology characterized by tubular structures. The detection of non-A/non-B viral particles, especially when refined to routine laboratory tests, may open the way for the specific diagnosis, exclusion of contaminated blood from transfusion, and eventual prophylaxis by vaccination.

Alanine Transaminase↗
PubMed1980

Diagnosis of type A hepatitis by fecal IgA antibody against hepatitis A antigen.

A method was developed for the early diagnosis of type A hepatitis. The method involved the detection of fecal antibody against hepatitis A antigen (HAAg). We followed 6 patients who contracted type A hepatitis in an outbreak for the fecal excretion of HAAg and antibody against HAAg (anti-HA) by immune electron microscopy. Fecal anti-HA appeared soon after the disappearance of HAAg, at around the zenith of serum transaminase, and persisted approximately 4 mo after the development of hepatitis. Fecal anti-HA was of IgA class, since it was completely absorbed by an anti-IgA column, but not affected by anti-IgG or anti IgM column. Owing to its early appearance and short duration, fecal anti-HA allows an early diagnosis of type A hepatitis by the test of a single specimen. Fecal anti-HA would be assumed to herald the termination of the period during which patients should be segregated from the community to prevent secondary infection.

Antibodies, Viral↗
PubMed1979

Free "small" and IgG-associated "large" hepatitis B e antigen in the serum and glomerular capillary walls of two patients with membranous glomerulonephritis.

Nephrotic syndrome developed in two children who carried hepatitis B virus. Both their serums contained hepatitis B surface antigen and hepatitis B e antigen (HBeAg). Two physicochemically and immunologically different categories of HBeAg activity were identified in their serums--i.e., small molecular (free) and large molecular (associated with IgG). Their kidney-biopsy specimens disclosed pathologic changes typical of membranous glomerulonephritis. By a fluorescent-antibody technic, HBeAg was found to be deposited in diffuse granular fashion, along glomerular capillary walls together with IgG and beta1C, but no deposition of hepatitis B surface antigen was detected. The presence of HBeAg in association with IgG both in the serum and in the kidneys of these patients suggests that HBeAg caused membranous glomerulonephritis by inducing the formation and deposition of immune complexes.

Antigen-Antibody Complex↗
PubMed1979

Demonstration of hepatitis B e antigen in hepatitis B core particles obtained from the nucleus of hepatocytes infected with hepatitis B virus.

Liver tissue infected with hepatitis B virus was homogenized and nuclei were separated by centrifugation. Hepatitis B core particles were obtained from the nucleus by the digestion with pronase followed by ultracentrifugation in a sucrose density gradient. Hepatitis B core particles were then treated with sodium dodecyl sulphate and 2 mercaptoethanol and tested for hepatitis B e antigen (HBeAg) by the haemagglutination method. The antigenicity of HBeAg was clearly demonstrated in hepatitis B core particles so treated, although untreated core particles did not reveal any detectable HBeAg activity. The localization of HBeAg in hepatitis B core particles was further supported by the results of a fluorescent antibody technique. When a frozen section of the liver infected with hepatitis B virus was stained with the specific rabbit antibody against HBeAg labelled with fluorescent isothiocyanate, only nuclei of hepatocytes were stained, in a similar distribution to hepatitis B core antigen visualized by fluorescent antibody against hepatitis B core antigen in a nearby section.

Cell Nucleus↗
PubMed1979

A large-scale survey on the prevalence of HBeAG and anti-HBe among asymptomatic carriers of HBV. Correlation with sex, age, HBsAG titre and s-GPT value.

During September and October of 1977, a total of 342,407 apparently healthy blood donors were screen for HBsAG by reversed PHA, and 6,342 (1.9%) asymptomatic carriers of HBV were identified. Prevalence of HBeAG and anti-HBe among HBV carriers was tested by our immunodiffusion method after serum samples had been concentrated threefold. The results were evaluated with reference to sex and age of donors, as well as HBsAG titre and s-GPT level in the serum. HBeAG was found slightly but significantly more often in male donors than in female donors (19.1 vs. 16.7%). In contrast, anti-HBe was found less frequently in males than in females (49.6 vs. 53.1%). Frequency of HBeAG decreased, while frequency of anti-HBe increased with age both in male and female carriers. The prevalence of HBeAG increased in parallel with the titre of HBsAG, whereas the prevalence of anti-HBe was approximately reciprocal to it. An abnormally high value of s-GPT (41 KARMEN U/ml or more) was found in 10.0% of the carriers with HBeAG, contrasting with 3.4% of those with anti-HBe.

Acute Disease↗
PubMed1979

Application of microtiter solid-phase radioimmunoassay to the determination of hepatitis B e antigen.

Microtiter solid-phase radioimmunoassay (micro-SPRIA) was applied to the detection of hepatitis B e antigen (HBeAg) in the serum. Antibody against HBeAg to coat the microtiter plate and for radiolabeling was obtained from the serum of asymptomatic carriers of hepatitis B surface antigen by an affinity column of partially purified HBeAg. The micro-SPRIA was sensitive and could be performed without prior concentration of the test serum. HBeAg was detected in 21 (35%) out of 60 serum samples positive for hepatitis B surface antigen, all of which were negative by the conventional immunodiffusion method even after they had been concentrated threefold.

Binding Sites↗
PubMed1979

A receptor for polymerized human and chimpanzee albumins on hepatitis B virus particles co-occurring with HBeAg.

A receptor for polymerized human serum albumin was demonstrated on Dane particles as well as on 20-nm hepatitis B surface antigen particles, isolated from asymptomatic carriers of hepatitis B virus who were positive for HBeAg. In contrast, such receptor was not born by 20-nm hepatitis B surface antigen particles obtained from carriers positive for antibody to HBeAg. Hepatitis B surface antigen particles with the receptor were heavier than those without, and when treated with pronase, they became lighter and lost the receptor. The receptor is responsible for the agglutination of erythrocytes coated with polymerized human serum albumin by the serum of patients with Type B hepatitis and asymptomatic carriers, which have been attributed to autoantibodies directed to denatured albumin molecules. When albumin fractions of chimpanzees were polymerized with glutaraldehyde, they also bound with the receptor on hepatitis B surface antigen. Polymerized albumin fractions of all the other experimental animals without susceptibility to hepatitis B virus, however, failed to bind with the receptor. These results seem to suggest a possible role of the receptor on Dane particles (presently accepted hepatitis B virions) for polymerized albumin molecules in infecting hepatocytes both in humans and chimpanzees.

Animals↗
PubMed1979

PPD-induced immunoglobulin production in human peripheral blood lymphocytes. I. Necessary conditions for inducing the response.

The ability of PPD to induce Ig production in human PBL was investigated. PPD proved to be a good B cell activator for inducing polyclonal Ig production in PBL from healthy Japanese. Comparative studies of this response with PWM-induced Ig production showed that the cellular mechanisms involved in the two responses were different. First, PBL from an atypical individual with a deficient IgM production to PWM responded normally to PPD with IgM production as well as IgG production. Secondly, in IgG production, the effects of the two mitogens (PPDand PWM) were additive. An analysis of the cellular requirements in PPD-induced Ig production clearly demonstrated that T cells played a role in this response as well as in the PWM-induced response. However, the head-to-head comparative study on the titration curves of helper T cells in the two responses showed that PWM-induced helper activity was 2 to 5 times more effective than PPD-induced helper activity. Moreover, PPD-induced helper activity was shown to be more sensitive to ionizing radiation than was PWM-induced helper activity. Thus, this system of PPD-induced Ig production may provide a useful tool for understanding the human antibody production system as well as the PWM-induced response.

B-Lymphocytes↗
PubMed1979

Effects of concanavalin A-induced cells on the proliferative response of T cells. Concanavalin A-induced suppressor and amplifier cells to the proliferative response of human T cells to trinitrophenyl-modified autologous lymphocytes.

Effects of Con A-induced human mononuclear cells on the proliferative response of peripheral T cells were examined by using TNP-modified autologous lymphocytes as stimulator cells. Cells induced by incubation with Con A contained both suppressor cells and amplifier cells. The former were induced from nylon wool-nonadherent T cells and these precursor cells were sensitive to mitomycin treatment. On the other hand, amplifier precursor cells were nylon wool-nonadherent T cells and were resistant to mitomycin treatment. Cell proliferation was required for the induction of suppressor cells but not for the induction of amplifier cells. Con A-induced suppressor effector cells were both nylon wool-adherent and nonadherent cells, on the contrary, Con A-induced amplifier effector cells were nonadherent cells. A small number of macrophages enhanced the suppressive activity of nonadherent T cells when added at the induction phase of suppressor T cells.

Cell Adhesion↗
PubMed1979

Shift from free "small" hepatitis B e antigen to IgG-bound "large" form in the circulation of human beings and a chimpanzee acutely infected with hepatitis B virus.

Hepatitis B e antigen (HBeAg) occurs both free and in association with IgG in the circulation of individuals infected with hepatitis B virus (HBV). We determined free and IgG-bound HBeAg forms separately in the serum of humans and a chimpanzee acutely infected with HBV. In a patient with laboratory acquired HBV infection, the proportion of free HBeAg gradually decreased from 89% to 23%. A similar shift from free to IgG-bound form of HBeAg was invariably observed in 5 additional patients with acute Type B hepatitis. In a chimpanzee that had been experimentally inoculated with HBV, free HBeAg appeared first, then gradually and completely shifted to the IgG-bound form. Finally, IgG-bound HBeAg disappeared, and antibody to HBeAg was detectable in the serum. The determination of both free and IgG-bound forms of HBeAg may provide valuable information, because their ratio reflects the stage and prognosis of acute HBV infection.

Acute Disease↗