Search PubMed⌕ Search

Biomedical subjects

P Hauser

Publications and source records attributed to P Hauser.

At least 91 records · Page 5Linked to original sources
PubMed1987

Reactogenicity and immunogenicity of different lots of a yeast-derived hepatitis B vaccine.

Several lots of a yeast-derived hepatitis B vaccine at different doses and a 20 micrograms dose of plasma-derived vaccine were tested in young healthy adults and compared with respect to risk of hypersensitivity reactions, reactogenicity, and immunogenicity. No signs of hypersensitivity either pre-existing or vaccine-induced were observed. Reactogenicity was low and similar in all vaccine groups. It was not dose related and unaffected by the number of injections. Immunogenicity was evaluated for a 0, 1, 2, and 12 month vaccination schedule. Seroconversion rates (greater than or equal to 10 IU/l) were not significantly different between the purified yeast- and plasma-derived vaccines one month after the second vaccination whereas the percentage of seroconversion was slightly lower in the groups receiving only partly purified recombinant vaccines. Although geometric mean titres induced by the plasma-derived vaccine were somewhat higher after the first months, the antibody titres induced by the recombinant vaccine were at least as high as those elicited by a plasma-derived vaccine following the booster dose.

Antigens↗
PubMed1987

Development of a hepatitis B vaccine from transformed yeast cells.

The production in yeast cells of the recombinant DNA hepatitis B vaccine of SmithKline Biologicals involves an optimized fermentation process followed by cell disruption and extraction, together with other soluble yeast components of the surface antigen of the hepatitis B virus. The subsequent purification process includes precipitation steps, ion exchange and gel permeation chromatography, and caesium chloride ultracentrifugation. The yeast-derived antigen occurs as spherical particles containing the non-glycosylated HBsAg polypeptide, lipid, and Tween 20. The purity of the polypeptide is above 95% and confirmed by the absence of an immune response to yeast-derived contaminants in vaccinees. Yeast DNA levels were less than 10 pg/vaccine dose. Various biochemical analyses showed that the recombinant polypeptide was faithfully expressed and did not undergo unwanted processing or degradation during fermentation or purification. These results indicate that the recombinant HBsAg can be effectively produced in yeast and processed to a high degree of purity to yield HBsAg particles displaying most of the characteristic properties of plasma-derived HBsAg.

Amino Acid Sequence↗
PubMed1983

Reactivity and immunogenicity of bivalent (AC) and tetravalent (ACW135Y) meningococcal vaccines containing O-acetyl-negative or O-acetyl-positive group C polysaccharide.

The immunogenicity and the reactivity of two bivalent (AC) and two tetravalent (ACW135Y) meningococcal vaccines containing either the O-acetyl-positive or the O-acetyl-negative group C polysaccharide were compared in healthy adolescent and adult volunteers. The vaccines contained high-molecular-weight, purified capsular meningococcal polysaccharides and were administered subcutaneously at a dose of 50 micrograms for each polysaccharide. Reactivity was low for all vaccines, and the tetravalent vaccines were not significantly more reactive than the bivalent vaccines. Immunogenicity was measured by assay of bactericidal antibodies in pre- and postvaccination sera. More than 90% of the vaccines had at least a fourfold increase in the bactericidal antibody titer against each group of meningococcus represented in the vaccines. Addition of polysaccharide W135 and polysaccharide Y to polysaccharides A and C did not alter the immunogenicity of the latter polysaccharides. Thus, there is no evidence of antigenic competition with the tetravalent vaccine. Comparison of the antibody response to the O-acetyl-positive and the O-acetyl-negative variants of group C polysaccharide in the bivalent vaccines, as measured by both bactericidal and enzyme-linked immunosorbent assays, indicates that in adults, the two types of group C polysaccharide are similarly immunogenic.

Adolescent↗
PubMed1982

Immunogenicity and reactogenicity of new multivalent pneumococcal vaccines.

In a study conducted in two phases at one month's interval, 22 healthy adult volunteers received a tetravalent (1, 3, 4, 12F) polysaccharide pneumococcal vaccine; 21 other subjects received another tetravalent (14, 18C, 19F, 23F) vaccine and 25 received a pentadecavalent vaccine (1, 3, 4, 6A, 7F, 8, 9N, 11A, 12F, 14, 15F, 18C, 19F, 23F). Placebo was given under single blind conditions to eleven subjects in the first phase of the study and to 24 subjects in the second phase of the study. The vaccines were well tolerated giving rise to transient local reactions in a small proportion of subjects. Results obtained indicate that all 15 polysaccharides are satisfactorily immunogenic. Results so far obtained can be described as encouraging. Further studies to investigate the reactogenicity and immungenicity of multivalent pneumococcal polysaccharide vaccines with a greater number of serotypes are under way.

Adolescent↗
PubMed1980

Lymphocyte-macrophage-fibroblast co-operation in the inflammatory degradation of cartilage and connective tissue.

In tissue culture models of cartilage and connective tissue degradation, rabbit macrophages and fibroblasts are both independently capable to degrade cartilage proteoglycan due to the secretion of a metal-dependent neutral proteinase. However, only the fibroblasts significantly degrade the collagen due to a sufficient production of collagenase. Macrophages produce factor(s) that stimulate the secretion of collagenase and the degradation of collagen by fibroblasts. Soluble products released by stimulated lymphocytes increase that production and also markedly enhance the secretion of proteoglycan-degrading proteinase and of collagenase by the macrophages. These data support the view that macrophages and fibroblasts are among the main effector cells of cartilage degradation in rheumatoid arthritis and that they are regulated in this function by secretory products of nearby lymphocytes.

Animals↗
PubMed1979

Macrophage-fibroblast interactions in collagenase production and cartilage degradation.

Rabbit bone-marrow macrophages and fibroblasts were cultured, independently or together, with pieces of 35S-labelled cartilage or at the surface of dried [14C]collagen gels. Each type of cell, cultivated alone, rapidly degraded the proteoglycan of cartilage, but only the fibroblasts degraded collagen. The co-culture of both types of cell had no consistent effect on the rate of proteoglycan degradation, but it stimulated the rate of collagen degradation. In parallel, the accumulation of collagenase in the culture fluid was enhanced but not that of neutral proteinase. Coinditioned media from macrophage cultures added to cultures of fibroblasts had the same effect as the living macrophages in stimulating the production of collagenase. Their action was itself enhanced when the macrophages had been activated by concanavalin A-stimulated spleen-cell factors. These data suggest that fibroblasts may act as effector cells in producing collagenase and degrading collagen in response to soluble factors released by macrophages under the control of lymphocyte factors.

Animals↗
PubMed1978

Degradation of cartilage proteoglycans by a neutral proteinase secreted by rabbit bone-marrow macrophages in culture.

When cultivated together with pieces of cartilage biosynthetically labelled with 35S in their proteoglycans, rabbit macrophages, differentiated in vitro from bone-marrow cells, cause the release of soluble 35S-labelled material into the culture medium. This process is inhibited by killing the macrophages or by cycloheximide treatment, and is due to the secretion by the cells of a metal-dependent neutral proteinase capable of degrading cartilage proteoglycan subunits into fragments of high molecular weight. Enzyme activity is optimum at about pH7, and is inhibited by EDTA, o-phenanthroline, cysteine or serum, but not by di-isopropyl phosphorofluoridate nor by 4-hydroxymercuribenzoate. The effect of EDTA is partially reversed by Co2+ or Zn2+ ions. The enzyme is eluted from Sephadex G-150 columns as a single peak of material (apparent mol.wt. 17000) that contains also most of the proteolytic activity exerted by culture media on Azocoll (denatured collagen) or on casein. The possible role of this metalloproteinase in chronic inflammatory processes is discussed, particularly in connection with joint erosions in rheumatoid arthritis.

Animals↗
PubMed1976

Analytical study of microsomes and isolated subcellular membranes from rat liver. V. Immunological localization of cytochrome b5 by electron microscopy: methodology and application to various subcellular fractions.

The localization of cytochrome b5 on the membranes of various subcellular organelles of rat liver was studied by a cytoimmunological procedure using anti-cytochrome b5/anti-ferritin hybrid antibodies and ferritin as label. For this study, highly purified and biochemically characterized membrane preparations were employed. Outer mitochondrial membranes were found to be heavily labeled by the hybrid antibodies whereas Golgi and plasma membranes were not marked by the reagent. Peroxisome membranes were moderately labeled by the hybrid antibodies, suggesting that they may contain some cytochrome b5. The preparation and purification of hybrid antibodies without peptic digestion is described and an analysis made of the composition of the final reagent product.

Animals↗