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Biomedical subjects

U Heinricy

Publications and source records attributed to U Heinricy.

6 recordsLinked to original sources
PubMed1996

Immune response to hepatitis A virus capsid proteins after infection.

This study was undertaken to determine the immune response of humans to viral capsid polypeptides of hepatitis A virus (HAV) after natural infection, which is very important for vaccine development. Antiviral capsids in 73 serum samples from patients with acute and chronic HAV infections were analyzed by immunoblotting against individual HAV capsid polypeptides (VP1, VP2, VP3, and VP4) by using a cell culture-based HAV antigen. For reference, total anti-HAV immunoglobulin G (IgG) and anti-HAV IgM were also determined by radioimmunoassay. As a result, a dominant immune response against VP1 (98% IgG, 94% IgM) was found in the acute phase. However, many other sera also reacted with VP0 (88% IgG; 35% IgM) and VP3 (81% IgG and 29% IgM). In contrast to the acute phase, anti-VP1, anti-VP0, and anti-VP3, IgG antibodies against all three viral proteins (29, 29, and 73% respectively), especially those against VP3, were found years after onset of HAV disease and over long periods in the sera of hepatitis patients. These results suggest that antibodies for capsid polypeptides are present over an extended period in the sera of HAV-infected patients. They are likely of importance in maintaining long-term immunity.

Capsid↗
PubMed1990

Simultaneous vaccination for hepatitis A and B.

Seronegative volunteers (15) were vaccinated at three 1-month intervals with a combined hepatitis A and B vaccine. The vaccine contained a killed hepatitis A vaccine made from hepatitis A virus (HAV) propagated in diploid human fibroblast cell cultures and hepatitis B surface antigen (HBsAg) produced in yeast. After only one injection, all volunteers developed neutralizing antibodies for HAV with antibody titers comparable to those found after gamma globulin administration. Compared with the antibody titers in sera of volunteers vaccinated with HAV vaccine alone, the antibody titers against HAV were significantly higher in the sera of the volunteers simultaneously vaccinated against hepatitis B virus (HBV) after three vaccinations. Of 15 volunteers, 14 seroconverted against HBV after three injections. In 11 volunteers tested 48 weeks after vaccination, antibody titers against HAV and HBV remained high.

Adult↗
PubMed1989

Immunogenicity of a killed hepatitis A vaccine in seronegative volunteers.

32 volunteers who lacked antibody to hepatitis A virus (HAV) received, at intervals of one month, three injections of a killed vaccine made from HAV propagated in diploid human fibroblast cell cultures. In 16 the vaccine was coupled with aluminium hydroxide as adjuvant. The serconversion rates measured by radioimmunoassay, with and without adjuvant respectively, were 13% and 25% at four weeks, 81% and 89% at eight weeks, and 94% and 100% at twelve weeks. Four weeks after the third injection all volunteers had high neutralising antibody titres. Twelve weeks later the titres of anti-HAV and anti-HAV neutralising antibodies had not declined.

Adult↗
PubMed1989

Acid stability of hepatitis A virus.

The acid stability of unpurified and highly purified hepatitis A virus (HAV) was tested and compared with that of poliovirus type 1, coxsackievirus types A9 and B1 and echovirus type 9. Only HAV had a high residual infectivity after 2 h of exposure to pH 1 at room temperature, remaining infectious for up to 5 h. At 38 degrees C, pH 1, HAV remained infectious for 90 min. Highly purified HAV was found to be infectious for 8 h at pH 1 and room temperature. This indicates that the increased stability is not due to protection by cellular material attached to the virus, but is a virus-specific marker. Under the same conditions, at pH 1 and room temperature, unpurified and highly purified HAV antigens were traceable for 5 and 4 h respectively.

Cell Line↗
PubMed1987

Properties of a hepatitis A virus candidate vaccine strain.

This paper describes the biophysical and biochemical properties as well as electron microscopical studies of a candidate hepatitis A vaccine strain propagated in human fibroblast cells. Our results indicated that, in CsCl, the density of hepatitis A virus (HAV) from cell culture supernatant and of HAV extracted from infected cells was influenced by the quantity of lipid material associated with HAV. Antigenicity of untreated HAV, therefore, was detected primarily in low density CsCl fractions (1.11 g/ml, 1.21 g/ml). After lipid reduction with NP40 detergent or chloroform/Genetron, antigenicity and infectivity were primarily detected in high density CsCl fractions (1.31 g/ml). Electron microscopy demonstrated a strong association between membranous material and virus particles of low density in CsCl as well as virus-like particles in ultrathin sections of HAV-infected human fibroblast cells. The uncovered virus particles banded in the 1.31 g/ml dense CsCl fraction lacked lipid material. The s value was 79 for 1.19 g/ml to 1.22 g/ml dense HAV and 147 for 1.29 g/ml to 1.33 g/ml HAV. Autoradiography of the radioiodinated dense HAV revealed some proteins with high Mr (120K to 67K) and others with low Mr (37K to 15K).

Fibroblasts↗