Search PubMed⌕ Search

Biomedical subjects

E Neter

Publications and source records attributed to E Neter.

At least 73 records · Page 4Linked to original sources
PubMed1974

Participation of lipopolysaccharide genes in the determination of the enterobacterial common antigen: analysis of R mutants of Salmonella minnesota.

A series of R (rough) Salmonella minnesota mutants with rfb, rfe, and rfa mutations leading to various defects in the biosynthesis of cell wall lipopolysaccharide was analyzed as to their enterobacterial common antigen (CA) content. All mutants that had functional rfe genes were CA(+) as is the wild-type parent. This includes mutants with the most defective lipopolysaccharide core types, demonstrating that core structures are not a necessary part of CA. All rfe(-) mutants (complete lipopolysaccharide core, defective synthesis of O side chains) were defective in the synthesis of CA. A smooth strain was accidentally found to be CA(-); the mutation responsible for this defect was also located, like rfe, very close to ilv.

Antigens, Bacterial↗
PubMed1972

Hemagglutinin response of human subjects to common enterobacterial antigen.

Ten human volunteers were immunized intravenously with ethanol-soluble common enterobacterial antigen (CA) obtained from Escherichia coli O111. The immunogen contained 6 mg/ml, excluding salts. The antigen was given in amounts of 2 ml each in dilutions of 1:250 (48 mug) and 1:125 (96 mug), respectively, 1 week apart. Serum specimens were obtained prior to immunization and 1 week after the last injection. The CA hemagglutinins were titrated by means of the passive hemagglutination test, with CA from E. coli O14 as indicator antigen. The injections were well tolerated without side-effects by all subjects. A significant (> fourfold) increase in the titers of CA hemagglutinins was observed following immunization in 9 out of 10 volunteers. These results indicate the feasibility of immunization with CA of human subjects and suggest exploration of immunization against infection caused by Enterobacteriaceae producing this common enterobacterial antigen.

Antibodies, Bacterial↗
PubMed1972

Immunogenicity of the common enterobacterial antigen produced by smooth and rough strains.

Enterobacteriaceae share a common antigen (CA). This antigen exists as a powerful immunogen, when produced by Escherichia coli O14, and as a minimally effective immunogen, when present in cultures of most other smooth strains. The present study was directed toward the assessment of immunogenicity of this antigen produced by various rough mutants and their parent strains as well as that of viable and nonviable bacterial suspensions. Rabbits were immunized intravenously, and the passive hemagglutination test was used for the quantitation of CA antibodies. The following results were obtained. (i) Immunization of rabbits with viable or heat-killed (1 hr, 100 C) suspensions of smooth parent strains resulted in only slight or insignificant antibody production. Of seven additional smooth strains of Enterobacteriaceae tested, none induced CA antibodies upon immunization with killed (1 hr, 100 C) suspensions, and only two engendered antibodies in moderate titers when viable suspensions were used, possibly due to the presence of undetected R mutant cells. (ii) In contrast, administration of viable suspensions of the corresponding mutant strains, regardless of core types, including E. coli R1, R2, R3, and Salmonella Ra types, caused a significant antibody response. (iii) The immunogenicity of R mutants differed strikingly, inasmuch as mutants with the R1 core [E. coli O8(-):K27(-)(R) and Shigella boydii type 3(-)(R)] engendered CA antibodies when heated suspensions were administered, in contrast to heated suspensions of mutants with the R2, R3, and Ra cores. (iv) Viability per se is not an abolute requirement for immunogenicity of R2 mutants, since CA antibodies were engendered by suspensions killed at 60 C or by merthiolate or formaldehyde. (v) Ethanol fractionation revealed that immunogenic CA of the R1 mutant is ethanol-insoluble and that of the parental smooth strain is ethanol-soluble; thus, CA of R1 mutants resembles that of E. coli O14 in both immunogenicity and ethanol insolubility.

Animals↗
PubMed1972

Biochemical basis of the immunogenicity of the common enterobacterial antigen.

Of the numerous members of the family Enterobacteriaceae only a few strains, notably Escherichia coli O14 and R mutants of the E. coli R1-core type, engender antibodies against the common enterobacterial antigen (CA) following immunization of rabbits with heated suspensions or culture supernatants; other members produce nonimmunogenic CA of identical serological specificity. The biochemical basis of the immunogenic properties of CA of the former strains was investigated by determining the relationship between the CA determinant and the lipopolysaccharide molecule. Lipopolysaccharides extracted from R mutants of the E. coli R1-core type or of E. coli O14 by the phenol-chloroform-petrol ether method contain the CA determinant, in contrast to extracts of other CA-producing R mutants. This is evident from the observation that only the former absorb CA antibodies, utilizing erythrocytes coated with alkali-treated lipopolysaccharide preparations. Based on the findings that CA of R mutants of E. coli R1-core type follows lipopolysaccharide during all purification steps and that alkali treatment increases its affinity for erythrocytes parallel to that of the lipopolysaccharide, it is concluded that the CA determinant either is part of the lipopolysaccharide molecule or is strongly complexed with it. It is suggested that this association between CA and the lipopolysaccharide of E. coli R1-core type and E. coli O14 accounts for the heat stability of the immunogenicity of CA of these unusual strains.

Adsorption↗
PubMed1972

Production by Aeromonas of common enterobacterial antigen and its possible taxonomic significance.

In a study of production of the common enterobacterial antigen (CA) by members of the Aeromonas group, ten strains of A. shigelloides, nine strains of A. hydrophila, and nine strains of A. salmonicida were used. Passive hemagglutination and hemolysis tests as well as the hemagglutination-inhibition procedure revealed that all strains of A. shigelloides, in contrast to the strains of the other two species, produce this antigenic determinant. The antigen of A. shigelloides was demonstrated even when the supernatant fluids of agar-grown cultures were used in a dilution of 1:1,000, whereas 10-times concentrated supernatant fluids obtained from the other two species were negative. Supernatant liquids of cultures of A. shigelloides failed to induce a significant CA immune response in rabbits; nonetheless, the animals were primed immunologically and responded with prompt production of CA antibodies in significant titers to a booster injection of a subeffective dose of CA obtained from Salmonella typhimurium. Strains of A. hydrophila and A. salmonicida neither induced CA antibody formation nor primed the animals. It is concluded that of the three species of the Aeromonas group only A. shigelloides, which may produce O antigen cross-reacting with Shigella sonnei and which has been isolated from patients with dysentery or gastroenteritis, produces CA. Production of this antigen, therefore, may help to characterize microorganisms belonging or related to the family Enterobacteriaceae.

Aeromonas↗