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Biomedical subjects

E Neter

Publications and source records attributed to E Neter.

At least 55 records · Page 3Linked to original sources
PubMed1977

Effect of heat on antigenicity and immunogenicity of the antigenic determinant shared by Haemophilus influenzae type b and Escherichia coli K100.

Escherichia coli K100 produces an antigenic determinant similar to, or identical with, the capsular antigen of Haemophilus influenzae type b. Studies of the effects of heat on the immunogenicity, erythrocyte-modifying capacity, and antigenicity of this cross-reacting antigen (CRA) revealed the following findings. Immunization of rabbits with viable or formaldehyde-killed suspensions of E. coli K100, producing CRA, engendered CRA antibodies in significant titers, as demonstrated by hemagglutination of erythrocytes modified by H. influenzae type b antigen. Heating of the suspensions for 1 h at 56 or 100 degrees C destroyed the immunogenicity of CRA, and the heated suspensions did not prime for a secondary antibody response. Supernatants of heated suspensions also were non-immunogenic. Repeated freezing and thawing of heated suspensions of E. coli K100 or their supernatants did not restore immunogenicity. Heat also abolished the immunogenicity of H. influenzae type b. The loss of immunogenicity of CRA of E. coli K100 by heat was not due to alteration of the antigenic determinant, since heated suspensions and supernatants thereof modified erythrocytes for agglutination by H. influenzae type b antiserum. The latter supernatants also inhibited hemagglutination by H. influenzae type b antibodies and absorbed the latter. We conclude that striking differences exist in the effects of heat on CRA on the one hand and of enterobacterial common antigen and lipopolysaccharide O antigen of enteric bacteria on the other. Heating of the latter two antigens does not abolish their priming effect, and repeated freezing and thawing restores the immunogenicity of heated antigens.

Antibodies, Bacterial↗
PubMed1977

Effect of serum from various animal species on erythrocyte attachment of endotoxins and other bacterial antigens.

Lipopolysaccharide O antigens (endotoxins) and other bacterial antigens readily attach to erythrocytes in vitro. This attachment is prevented by certain mammalian and avian sera. In this study, the inhibitory capacity of sera from lower animals was compared with that of higher animals for a total of 30 species. Antigens and the corresponding antisera included both crude O antigens and purified lipopolysaccharide preparations, the common enterobacterial antigen from Escherichia coli O14, the Vi antigen from Citrobacter ballerup, the polyribose-phosphate antigen from Haemophilus influenzae type b, and the crude teichoic acid antigen from Staphylococcus aureus. Antigen and serum mixtures were incubated at 37 degrees C for 30 min and used for erythrocyte modification; failure of hemagglutination by homologous bacterial antiserum provided evidence of inhibitory capacity. Sera from the classes Mammalia and Aves were very strong inhibitors; those of Reptilia and Osteichthyes were moderate in activity, displaying variation within the classes; those of Amphibia and Chondrichthyes were minimal inhibitors; and those of Merostomata, Crustacea, and Lamellibranchiata displayed questionable or no inhibitory capacity. Inhibitory sera were active with all antigens tested. The findings suggest evolution of inhibitory factors consistent with the theory of two diverging lines of animal phylogeny based on embryological criteria and closely parallel the observations of an endotoxin-altering capacity in vertebrate sera that is not found in invertebrate sera or hemolymph.

Amphibians↗
PubMed1977

Antibody response to Serratia marcescens isolated from patients with malignant diseases.

Sixty-four patients with malignant diseases from whom Serratia marcescens was isolated from various sources were studied regarding their antibody responses to somatic O antigens of this microorganism. Antibodies were titrated by the passive hemagglutination test. An antibody response was considered present when either a fourfold or greater rise in antibody titers between two consecutive serum specimens was demonstrated, or when elevated titers (greater than or equal to 40 for serogroup O14 and greater than or equal to 160 for all others) were present in the first available specimen. Overall, 31% of subjects mounted an immune response, but there were differences depending upon the infection site. Seventy-one percent of patients with S. marcescens bacteremia responded immunologically; whereas the percentage for patients with Serratia present in the respiratory tract was only 22%, in the urinary tract, 31%, and in wounds, 26%. Documentation of an immune response to the patient's own infecting strain of Serratia aids in the differentiation between infection and contamination and possibly also between clinical disease and colonization. In addition, immunoglobulin samples collected in different decades were examined to determine whether the background level of antibodies to S. marcescens had changed in the general population over the years. No difference in antibody titers to 13 O antigens was observed in immunoglobulin preparations from 1951, 1962, 1971, and 1975.

Adult↗
PubMed1976

Strain-related differences in immunosuppressive effects of Enterobacteriaceae and their lipopolysaccharides on production in rabbits of antibody to enterobacterial common antigen.

Certain polysaccharides have been shown to inhibit the antibody response of rabbits to the common enterobacterial antigen (CA). The present investigation revealed that striking differences exist in the immunosuppressive effects of enteric bacteria and their lipolysaccharides (lps), depending upon CA production by the strains. Mixtures of immunogenic strains (Escherichia coli F2378 [R4], E. coli F470 [R1], or Shigella boydii F3140 [R]) and non-immunogenic CA-producing strains, such as E. coli O1, E. coli O113, Salmonella montevideo, and S. minnesota, as well as the R mutants E. coli F614 (R1), E. coli F757 (R1), and S. typhimurium his 642 (Ra), failed to elicit CA antibodies. In contrast, mixtures of the immunogen and CA-negative strains S. typhimurium his 386 (Ra) and S. minnesota P595 (Re) or R555 (Ra) yielded antibodies in titers similar to those elicited by the immunogen alone. Further, LPS of CA-positive but not of CA-negative strains exerted this immunosuppressive effect. Quantitative studies revealed that LPS of S. minnesota in amounts of 100 mug/ml was strongly immunosuppressive, in amounts of 20 mug/ml slightly effective, and in amounts of 4 mug/ml ineffective. It is postulated that hitherto unknown differences exist, either in composition or in configuration, between LPS obtained from different microorganisms to account for the strain-related differences in immunosuppressive effects and, further, that the immunosuppressive LPS interacts with immunogenic CA.

Animals↗
PubMed1976

Role of a lipopolysaccharide gene for immunogenicity of the enterobacterial common antigen.

It is known that only certain strains of the family of Enterobacteriaceae, notably rough (R) mutants with the type R1 or R4 core, evoked antibodies in high titers against the common enterobacterial antigen (CA) after immunization of rabbits with heated cell suspensions. The present investigation deals with genetic and immunochemical aspects of certain R1 and R4 mutants isolated from Escherichia coli 08 and various Shigella serotypes which, unexpectedly, do not induce CA antibody formation. Immunochemical and genetical (transduction and conjugation) experiments revealed that the rough phenotype of these special mutants was evoked by a mutation of pyrE-linked rfa gene, called rfaL, which is involved in translocation of O-specific polysaccharides onto the lipopolysaccharide core. The transduction of the defective rfaL, allele into appropriate rough recipients results in transductants which have simultaneously lost the ability to evoke CA antibodies. This finding suggests that a close connection exists between the function of the rfaL gene and the expression of CA immunogenicity in R1 and R4 mutants. One of the strains synthesized neither O-hapten nor CA, suggesting a mutation in a region equivalent to the rfe genes of Salmonella.

Animals↗
PubMed1976

Enterobacterial common antigen in rfb deletion mutants of Salmonella typhimurium.

The his-rfb deletion series of Salmonella typhimurium mutants characterized previously by Nikaido et al. was examined for the presence of the enterobacterial common antigen (ECA). All deletions not extending further to the left than the genes for cytidine phosphoabequose synthesis were ECA positive, whereas longer deletions (extending to the genes for thymidine diphosphorhamnose synthesis or further) were ECA negative. When these long-his-rfb deletion strains were studied further, it became clear that they (four out of four studied) had accumulated a second mutation, called rff, close to ilv, which prevented the synthesis of ECA. When rff- was replaced by rff+, the recombinants, now having the his-rfb deletion only, produced traces of ECA, showed reduced viability, increased sensitivity to sodium dodecyl sulfate (SDS) and to a lesser extent, to other anionic detergents, and accumulated secondary "suppressor" mutations upon storage. Such suppressor-containing mutants could be isolated by selecting for resistance to 1% SDS. Thirty of 46 SDS-resistant mutants studied had a second mutation, which alone prevented the synthesis of ECA, close to ilv. This ilv-linked mutation was similar to the rff mutation of the strains studied originally. The new rff mutation was similar to previously described rfe mutations in its close linkage to ilv and association with an ECA-negative phenotype. It differed from rfe, however, by not affecting the synthesis of the O antigens (O-6,7) of group C1. In Salmonella group C1, all ECA genes identified thus far are linked to ilv (rfe and/or rff) and none is linked to rfb.

Antigens, Bacterial↗
PubMed1975

Colonization by Enterobacteriaceae of the respiratory tract of children with cystic fibrosis of the pancreas and their antibody response.

Of 72 patients with fibrosis, 49 harbored Enterobacteriaceae in the respiratory tract, including Escherichia coli, Klebsiella, and Enterobacter. Colonization by two to four genera was documented in 29 subjects. Staphylococcus aureus was recovered from 44 of these 49 patients. The distribution of serogroups of E. coli was similar to that seen in patients with urinary tract infection. Antibody response against the O antigens of the patients' own Enterobacteriaceae was documented in 29 of these 49 children and encountered more often in patients with severe disease. Colonization by Enterobacteriaceae in the absence of Pseudomonas aeruginosa was seen more frequently in children with the mild form of the illness.

Adolescent↗
PubMed1975

Antibody response of patients with malignancies to bacteremia with gram-negative bacteria.

Antibody response, determined by means of the indirect bacterial hemagglutination tests, was studied in 58 consecutive patients with various malignancies whose blood culture yielded growth of Enterobacteriaceae or Pseudomonas and from whom serum specimens were obtained. Of these patients 59% had a significant antibody response. The invading microorganisms were Escherichia coli in 33 and Klebsiella in 19 subjects, an antibody response being documented with essentially equal frequency (60 and 57% of the subjects, respectively). Two patients had positive blood cultures for both E. coli and Klebsiella, one of whom had a significant response to one isolate only. A specific antibody resonse was documented in 67% of the subjects from whom blood for antibody titration was obtained at least 5 days after the blood culture, but from only 21% of patients whose serum was procured during the first 5 days after the blood culture. Similarly, such an antibody response was identified in 73% of subjects with two consecutive serum specimens, but in only 28% of the patients with a single serum specimen for antibody titration. Documentation of the immune response may be of diagnostic aid in differentiating between infection and contamination even in patients with underlying malignancy and under potentially immunosuppressive therapy.

Adolescent↗
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↗