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O Westphal

Publications and source records attributed to O Westphal.

10 recordsLinked to original sources
PubMed1979

A lipopolysaccharide-binding cell-surface protein from Salmonella minnesota. Isolation, partial characterization and occurrence in different Enterobacteriaceae.

1. Protein extracts obtained from Salmonella minnesota Re mutant cells by treatment with EDTA/NaC1 solution contain a protein which exhibits high affinity to bacterial lipopolysaccharides. The isolation and partial characterization of this lipopolysaccharide-binding protein is described. 2. The protein was purified from EDTA extracts by a two-step procedure consisting of ion-exchange chromatography on CM-Sephadex and preparative polyacrylamide gel electrophoresis at pH 9.5. The yield of the total purification procedure was around 16%. 3. The resulting protein preparation was homogeneous on the basis of disc gel electrophoresis, dodecylsulfate gel electrophoresis, isoelectric focusing in polyacrylamide gel and immunoelectrophoresis. 4. The isoelectric point of the protein was found to be 10.3 at 4 degrees C. Its molecular weight determined by dodecylsulfate gel electrophoresis is 15000. Its amino acid composition is characterized by the absence of histidine and proline, a low content in tyrosine and high amounts of alanine, lysine, aspartic and glutamic acid residues, or their respective amides. 5. The lipopolysaccharide-protein association was shown to be mainly due to ionic interactions of the basic protein with negatively charged groups (probably phosphate and pyrophosphate groups) of the lipid A moiety. 6. Purified lipopolysaccharide-binding protein is immunogenic in rabbits, thus enabling the preparation of specific antiserum. 7. The protein is located at the surface of Salmonella minnesota Re mutant cells as revealed by antiserum absorption with total bacteria. Ferritin-labelling studies further demonstrated that it is evenly spread over the entire cell surface. 8. Comparative antiserum absorption studies using smooth and rough strains of Salmonella minnesota, Salmonella typhimurium, Escherichia coli, Klebsiella and Shigella revealed the presence of lipopolysaccharide-binding protein (or a serologically cross-reacting antigen) in most of the strains tested. From these results the protein can be considered as a common antigen of Enterobacteriaceae.

Amino Acids↗
PubMed1979

[Protective role of Salmonella R mutants in Salmonella infection in mice (author's transl)].

NMRI mice were immunized with acetone-killed bacteria of 6 salmonella R mutants, 5 homologous and 6 heterologous Salmonella S forms and 3 E. coli R mutants. The animals were then challenged with graded amounts of live S. typhimurium. The results show that the protection obtained was dependent on the number of immunizing injections and on the time interval between them. Thus in the case of Salmonella R-mutants two immunizations increased the LD50 of challenge by an index of two (log 10) compaired to one immunization. A third immunization led to only a small further increase, the protection however, was longer lasting. A 3 fold immunization with two Salmonella typhimurium mutants, one SR- and one Ra form, led to a protection comparable to that obtained with S form bacteria. In contrast to the R-mutants, with Salmonella typhimurium S form a high degree of long-lasting protection was achieved already after a single immunization, and was not increased significantly by repeated injections. In animals immunized with Salmonella typhimurium S form the difference between non-lethal and 100% lethal challenge dose varied by a factor of 10 (one injection dose). In contrast, in animals immunized with Salmonella R mutants the above differences were more gradual extending over 3, 4 or more infection doses. This was also true for animals immunized with lower doses of S. typhimurium S form and for the non-immunized control animals. For comparison the protective effect of heterologous Salmonella S forms and of E. coli R-mutants was studied. These were found to be less effective in affording protection to Salmonella typhimurium than the above Salmonella R forms. The various strains used for immunization may be placed in the following sequence in order of decreasing protection: Salmonella typhimurium S form, Salmonella R-mutants, heterologous Salmonella S forms, E. coli R mutants. In a parallel investigation the antibody inducing properties of Salmonella R mutants and heterologous Salmonella S forms were studied. In all cases homologous hemaglutinating antibodies to all the strains used for immunization were detectable. In immunization with Salmonella R mutants in addition to homologous titres, agglutinating antibodies to Salmonella typhimurium S form were also produced in significant amounts. There was, however, no correlation between the time of appearance of protection and that of appearance of antibodies nor between the hight of antibody titres and degree of protection. The detection of agglutinins to the infecting microorganisms represents therefore no valid criterium for the effectiveness of R mutants and heterologous Salmonella S forms as protective vaccines. From the present results it is concluded that in addition to the O antigen one or more further cell components exist which are involved in rendering animals immune to Salmonella typhimurium and probably also to other Salmonella S form bacteria.

Agglutination Tests↗
PubMed1979

Preparation and properties of a standardized lipopolysaccharide from salmonella abortus equi (Novo-Pyrexal).

The paper describes the preparation of the lipopolysaccharide from Salmonella abortus equi as obtained by standardized methods. The include the extraction with pehnol/water followed by phenol/chloroform/petroleum ether extraction, ultra-centrifugation, electrodialysis and conversion to the uniform sodium salt form. Chemical composition and physico chemical properties are described. The preparation, which is free from contaminants, was tested for local Shwartzman reactivity, pyrogenicity, lethal toxicity, mitogenicity, reactivity towards complement and tumoricidal action.

Animals↗
PubMed1977

[The significance of immunology for man--intervention and change].

Classical immunological research has been mainly devoted to natural defense mechanisms against infections and to the development and action of vaccines. With the discovery of immune tolerance and following investigations on transplantation immunity, the concept of the immune response was generalized as the higher animal's ability to discriminate between "self" and "notself". Since then research has concentrated on cells and their products involved in these immune phenomena. Application of the vast knowledge in the field of modern immunology should aid greatly in the solution of many actual clinical problems and in alleviating public health hazards (parasitology, etc.) in the Third World.

Humans↗
PubMed1975

Immunological responses to Salmonella R antigens. The bacterial cell and the protein edestin as carriers for R oligosaccharide determinants.

Responses in rabbits to heat-killed Salmonella minnesota R mutants (chemotypes Ra, Rc and Re) were heterogeneous with respect to the amounts and specific haemagglutinin activities (SHAA) of IgM and IgG antibodies produced to each mutant. Amounts of antibodies in IgM and IgG fractions of sera were determined by quantitative precipitation. For comparison, antibodies were also isolated using an R oligosaccharide-specific immunoadsorbent and quantitated spectrophotometrically. SHAA (haemagglutinating units/mg antibody) of IgG antibodies were similar for all three mutants. In contrast, the Ra mutant induced IgM antibodies with the highest SHAA, while the Re mutant induced IgM antibodies 10-fold lower in activity. The ratio of the amount of IgM/IgG produced was approximately 1/1 for both the Ra and the Rc mutants, while the ratio for the Re mutant was about 1/2. Salmonella R oligosaccharide-protein conjugates (chemotypes Rb2, Rc and Re) were prepared, and the responses to these antigens were compared with those to the heat-killed mutants. The conjugates were specific for the given chemotype, and they were strongly immunogenic when incorporated into Freund's complete adjuvant and administered intramuscularly. Haemagglutinin titres were relatively high, but amounts of antibodies were considerably reduced when the conjugates were administered intravenously without adjuvant. Rabbits immunized with the conjugates in the same manner as with heat-killed R mutants produced predominantly IgM responses in all three cases.

Adsorption↗