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Biomedical subjects

J Heesemann

Publications and source records attributed to J Heesemann.

At least 181 records · Page 10Linked to original sources
PubMed1992

Ovalbumin blocking improves sensitivity and specificity of immunoglobulin M immunoblotting for serodiagnosis of patients with erythema migrans.

To improve the serodiagnosis of erythema migrans, we evaluated how sensitivity and specificity of immunoblotting are influenced by antigen concentration and blocking conditions. We found that an antigen concentration of 0.5 micrograms per lane in concert with ovalbumin blocking of the nitrocellulose provided the best results. In this case, 81% of the erythema migrans had positive immunoglobulin M tests, whereas only 33% were positive in a flagellum enzyme-linked immunosorbent assay (ELISA) and 28% were positive in a sonicate ELISA.

Antibody Specificity↗
PubMed1992

Improved serological diagnosis of Toxoplasma gondii infection by detection of immunoglobulin A (IgA) and IgM antibodies against P30 by using the immunoblot technique.

Immunoglobulin M (IgM) and IgA antibodies against the major surface protein of Toxoplasma gondii were determined in a total of 195 human sera and five human cerebrospinal fluids by using a P30 membrane extract and the immunoblot technique. By using two different T. gondii strains (RH and BK) simultaneously as antigens, we were able to demonstrate diagnostically important strain-specific human antibody responses in 4.5% of the samples tested. A comparison of the immunoblot technique with an IgM immunocapture enzyme-linked immunosorbent assay demonstrated that the IgM and IgA immunoblot seems to be of advantage in the diagnosis of acute toxoplasmosis in certain groups of patients, especially in the diagnosis of cerebral toxoplasmosis in patients with AIDS. The immunoblot technique described is easy to perform and might be useful as an additional serological assay for routine diagnosis of T. gondii infections.

Animals↗
PubMed1992

Aetiological role of bacteria associated with reactive arthritis in pauciarticular juvenile chronic arthritis.

BACKGROUND: The cause of juvenile chronic arthritis (JCA) is unknown. Pauciarticular JCA is the most common subtype and can be subdivided into early (type I) and late onset (type II) forms, the latter clinically resembling reactive arthritis. METHODS: The cellular immune responses to bacteria associated with reactive arthritis in blood and synovial fluid from 39 children with pauciarticular JCA, three children with classical reactive arthritis, and two children with psoriatic arthritis were examined. Specific titres of antibodies to bacteria in serum samples were measured in all patients. RESULTS: A bacteria specific synovial cellular immune response was found in two of three (67%) patients with reactive arthritis and 14 of 28 (50%) patients with pauciarticular JCA type II but only in one of 11 (9%) patients with pauciarticular JCA type I and none in patients with psoriatic arthritis. Six patients responded specifically to Chlamydia trachomatis and 11 to Yersinia enterocolitica. Antigen specific lymphocyte proliferation correlated poorly with the specific antibody response. CONCLUSIONS: These findings suggest that bacteria with associated reactive arthritis may have a causative role in pauciarticular JCA type II but not in JCA type I.

Adolescent↗
PubMed1992

Antibody response against 26 and 46 kilodalton released proteins of yersinia in yersinia triggered reactive arthritis.

Using an inhibition enzyme linked immunosorbent assay (ELISA) the serum antibody responses against released proteins of yersinia of molecular weights 26 and 46 kilodaltons were studied in 37 patients with and in 21 patients without reactive arthritis following yersinia infection. Although no difference was seen for the 46 kilodalton released protein, patients with yersinia triggered reactive arthritis had higher levels of antibodies against the 26 kilodalton released protein at the beginning of the disease than patients with uncomplicated yersiniosis. This may indicate an increased production of this protein in the early infection leading to poorer phagocytosis of the bacteria and thereby to the persistence of yersinia organisms within the arthritic host.

Adolescent↗
PubMed1992

[Prevalence of Borrelia burgdorferi antibodies in Hamburg blood donors].

One thousand regular blood donors of the Department of Transfusion Medicine at the University Hospital in Hamburg were screened for antibodies against the Lyme disease spirochete, B. burgdorferi. 7.2% were initially reactive in the enzyme immunoassay, 37.5% of which were confirmed by immunoblot. The seroprevalence of anti-B. burgdorferi antibodies thus is 2.7% in Hamburg blood donors. 25 of 27 positive donors received a physical exam, which did not reveal any symptoms of acute or chronic Lyme disease. 24 of these 25 donors were tested for B. burgdorferi-specific DNA in urine by polymerase chain reaction, which came out negative in all cases. Introduction of B. burgdorferi antibody screening is not regarded an effective means to prevent transfusion-transmitted Lyme disease.

Antibodies, Bacterial↗
PubMed1992

Pathogenetic role of Chlamydia, Yersinia and Borrelia in undifferentiated oligoarthritis.

We studied the cellular and humoral immune response to Chlamydia trachomatis, Yersinia enterocolitica and Borrelia burgdorferi in paired samples of peripheral blood and synovial fluid (SF) in undifferentiated oligoarthritis, reactive arthritis (ReA) and rheumatoid arthritis. Antigen specific lymphocyte proliferation was found in SF of 43% of patients with ReA and 34% of patients with undifferentiated oligoarthritis. C. trachomatis was the most frequent single agent. HLA-B27 was positive in 83% of patients with ReA and in 62% of patients with undifferentiated oligoarthritis with antigen specific lymphocyte proliferation. Antigen specific lymphocyte proliferation correlated poorly with the specific antibody response. Only chlamydial antigen was detected in SF cells using monoclonal antibodies. We conclude that some patients with undifferentiated oligoarthritis may have a forme fruste of ReA. This finding is important in view of recent evidence supporting the efficacy of antibiotic therapy in ReA.

Adult↗
PubMed1992

[New views on the pathogenesis and diagnosis of toxoplasmosis].

T. gondii is one of the most occurring human pathogenic parasites in Europe. While the majority of immunocompetent individuals with T. gondii infection do not present clinical symptoms, congenital toxoplasmosis and reactivation of a latent infection in immunocompromised patients (i. e. patients with AIDS) are of high clinical relevance. A classification of T. gondii isolates is not available so far, although it was possible to demonstrate strain differences by the use of several methods, i. e. by using monoclonal antibodies. T. gondii seems to be able to infect any mammalian cell. Host cell-derived as well as parasite-derived factors seem to be important for the contact between host cell and parasite and the subsequent internalization. Following invasion, T. gondii is located within a parasitophorous vacuole that does not fuse with lysosomes. The multiplication rate of these obligately intracellular growing parasites decreases during conversion from the tachyzoite stage to the bradyzoite stage. Finally, the bradyzoites-harbouring cysts persist for the lifetime of the host. Reconversion from bradyzoites to tachyzoites may occur in immunocompromised patients. Probably, IFN-gamma is involved in this process. In addition to serological methods, direct detection of T. gondii using PCR or demonstration of circulating antigens might be routinely used as diagnostical tools in the future. Determination of specific IgA antibodies, which can be evaluated using the immunoblot technique, seem to be important for early serological diagnosis. The use of recombinant antigens might be helpful in future diagnosis to circumvent discrepancies between serological test results which could have resulted from strain-specific differences.

Animals↗
PubMed1992

[Rapidity versus reliability: a critical analysis of the rapid diagnosis of mycobacterial infections with the polymerase chain reaction (PCR)].

In this contribution we analyzed the reliability and the diagnostic value of the results obtained by direct amplification of mycobacterial DNA from patient specimens. Presently, the PCR-method is not as sensitive as recommended culture techniques. In cases of low concentration of mycobacteria in specimens (microscopic negative!) false-negative PCR-results are not rare.

DNA, Bacterial↗
PubMed1991

Immunosuppression of the host and delivery of iron to the pathogen: a possible dual role of siderophores in the pathogenesis of microbial infections?

Iron is an essential growth factor for procaryotes as well as for eucaryotes. Microorganisms have developed specific iron-uptake systems by producing low-molecular weight iron-chelating compounds (siderophores). We have examined the effect of the siderophores desferrioxamine (DFO), desferrichrome (DFC), desferriaerobactin (DFAB) and desferrienterobactin (DFEA) on the mitogen-stimulated activation and proliferation of mouse T cells. The hydroxamate siderophores DFO, DFC and DFAB cause an immunosuppressive effect on T cells which is related to the iron complexation constant of the siderophores and can be reversed by equimolar ferric iron. In contrast, the catecholate siderophore DFEB and its ferrated derivative turned out to be cytotoxic for T cells. These results suggest a dual role of siderophores in the infectious process, i.e., growth enhancement of the invading pathogen and inhibition of the host immune defense.

Animals↗
PubMed1991

Recognition by peptide mapping of three different structural groups of outer membrane protein YOP-1 of Yersinia enterocolitica and Yersinia pseudotuberculosis.

The structural relation of YOP-1 of "european" and "american" Yersinia enterocolitica serotypes O:3, O:9, O:5,27, and O:8 and O:20, respectively, and Y. pseudotuberculosis serotypes I, II, and III was compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis and peptide mapping using Staphylococcus aureus protease V8. Apparent molecular weights of YOP-1 ranged from 206,000 (O:3) to approx. 180,000 (O:8). According to their respective peptide maps YOP-1 of the "european" and "american" Y. enterocolitica serotypes and Y. pseudotuberculosis serotypes could be assigned to three different groups. Evaluation of several isolates of Y. enterocolitica serotypes O:3, O:9, and O:8 by peptide mapping indicated that YOP-1 is conserved within a serotype. However, one serotype O:8 isolate differed from the consensus peptide pattern of the other serotype O:8 and O:20 isolates. The similarity of the peptide patterns of Yersinia serotypes which predominate in certain geographical locations, i.e., "european" and "american" Y. enterocolitica serotypes, suggest common evolution of YOP-1 of these serotypes independent of the evolution of the other serotypes.

Adhesins, Bacterial↗
PubMed1991

High incidence of serum antibodies to Escherichia coli O157 lipopolysaccharide in children with hemolytic-uremic syndrome.

Because the classic hemolytic-uremic syndrome has been etiologically linked to intestinal infections by Escherichia coli O157 and other verotoxin-producing E. coli (VTEC), we examined 22 consecutive children with acute hemolytic-uremic syndrome for the presence of VTEC, using microbiologic methods, and for a specific immune response to O157 lipopolysaccharide in acute-phase and follow-up sera, using the indirect hemagglutination assay and the immunoblot procedure. Of 22 children with enteropathic hemolytic-uremic syndrome, 15 (68%) had evidence of VTEC infection by culture of the pathogen or detection of free verotoxin in the feces, or both. Significantly elevated titers of short-lived agglutinins and IgM class antibodies against the O157 lipopolysaccharide were found in 20 (91%) of 22 patients, but not in two of three patients with non-O157 E. coli isolates or in healthy children or children with diarrhea caused by other enteric pathogens (p less than 0.01). The combined microbiologic and serologic procedures provided evidence for VTEC infection in all 22 patients. The high incidence of anti-O157 lipopolysaccharide antibodies in these patients indicates the predominance and the pathogenic potential of this serogroup. Both serologic techniques proved to be valuable tools to further characterize this form of hemolytic-uremic syndrome. Future studies on the induction of protective immunity seem warranted.

Antibodies, Anti-Idiotypic↗
PubMed1991

Combined use of released proteins and lipopolysaccharide in enzyme-linked immunosorbent assay for serologic screening of Yersinia infections.

An ELISA for the screening of serum antibodies to Yersinia species was developed using plasmid-encoded released proteins of Yersinia enterocolitica O:8 and lipopolysaccharide of Y. enterocolitica O:3 as a combined antigen. Of 43 sera from patients infected with one of six different Yersinia serotypes, 40 (93%) were positive in this assay. When tested using six serotype-specific ELISAs with the corresponding Yersinia bacteria as antigens, 38 (88%) were positive. This screening ELISA detects antibodies to all virulent yersiniae in one assay and offers the possibility for diagnosis of infections caused by Yersinia serotypes seen only occasionally and not usually included in the serotype-specific ELISAs. Thus, this ELISA offers a substantial advantage by saving time and money in routine laboratory work.

Adolescent↗
PubMed1991

Temperature-dependent expression of flagella in Legionella.

Legionella pneumophila, the causative agent of Legionnaires' disease, was analysed by electron microscopy for production of surface structures. Crystalline surface (S-) layers and fimbriae were not detected, but monotrichous flagellation was seen. Polyclonal antibodies specific for the 47 kDa flagellin subunit of L. pneumophila Philadelphia I were used in Western blots to confirm the presence of flagella subunits in various L. pneumophila strains tested, but the antiserum also reacted with flagellin subunits of L. micdadei, L. hackelia [serogroup (SG) 1 and SG2] and L. longbeachae (SG2). Flagellation of Legionellae was shown to be temperature regulated. When the growth temperature of virulent and avirulent of strain L. pneumophila Philadelphia I was shifted from 30 degrees C to either 37 or 41 degrees C, a decrease in the percentage of flagellated bacteria within the population was observed.

Bacterial Outer Membrane Proteins↗
PubMed1991

Identification of a virulence-associated antigen of Toxoplasma gondii by use of a mouse monoclonal antibody.

A monoclonal antibody generated against the mouse-lethal RH strain of Toxoplasma gondii was developed. Tachyzoites of virulent and avirulent T. gondii isolates grown in permanent macrophage cell cultures were examined for differences in reactivity with this antibody. Virulence of these Toxoplasma isolates was quantified by injecting different numbers of tachyzoites into NMRI mice and observing the animals for signs of infection or death. The monoclonal antibody identified a 23-kDa antigen expressed by the mouse-lethal strains BK and RH, whereas this antigen was not detected in low-mouse-virulent strains, which were all clinical isolates from Europe. Using Western blot (immunoblot), immunofluorescence, and immunoelectron microscopy, we localized the 23-kDa antigen to the membrane compartment. From these results, we suggest that this 23-kDa antigen is a marker of strain virulence upon which a virulence classification of T. gondii may be based.

Animals↗
PubMed1991

Distribution, expression, and long-range mapping of legiolysin gene (lly)-specific DNA sequences in legionellae.

The legiolysin gene (lly) cloned from Legionella pneumophila Philadelphia 1 confers the phenotypes of hemolysis and browning of the culture medium. An internal lly-specific DNA probe was used in Southern hybridizations for the detection of lly-specific DNA in the genomes of legionellae and other gram-negative pathogenic bacteria. Under conditions of high stringency, the lly DNA probe specifically reacted with DNA fragments from L. pneumophila isolates; by reducing stringency, hybridization was also observed for all other Legionella strains tested. No hybridization occurred with DNAs isolated from bacteria of other genera. The lly gene was mapped by pulsed-field gel electrophoresis to the respective genomic NotI fragments of Legionella isolates. By using antilegiolysin monospecific polyclonal antibodies in Western blots (immunoblots), Lly proteins could be detected only in L. pneumophila isolates.

Animals↗