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C Nauciel

Publications and source records attributed to C Nauciel.

At least 37 records · Page 2Linked to original sources
PubMed1994

Comparison of polymerase chain reaction and non-radioactive hybridization techniques for the identification of Mycobacterium avium strains.

A polymerase chain reaction able to amplify specifically a 205-base-pair DNA fragment of Mycobacterium avium genome was used and compared to a nonradioactive hybridization assay (AccuProbe) and to conventional biochemical identification. The PCR approach to diagnosis of M. avium infection is a valid diagnostic alternative to the more classical procedures.

Base Sequence↗
PubMed1994

Molecular epidemiology of Legionella pneumophila serogroup 1 by ribotyping with a non-radioactive probe and PCR fingerprinting.

Hybridization with acetylaminofluorene-labelled 16 + 23 S rRNA from Escherichia coli was used to detect DNA polymorphism among Legionella pneumophila serogroup 1 isolates. Isolates from unrelated patients showed at least four different rRNA restriction patterns, whereas those from related patients showed a single pattern. Amplification of genomic regions with an arbitrary primer by polymerase chain reaction was used to further analyze the isolates. Related isolates showed closely related patterns while unrelated isolates displayed six distinct patterns. We could differentiate the majority of unrelated isolates with the combination of the patterns obtained with the ribotyping and the PCR fingerprinting, while strains from the same outbreak remained highly related. The ribotyping and the PCR fingerprinting are proposed as useful and easy to perform epidemiological markers of L. pneumophila serogroup 1 infection.

Base Sequence↗
PubMed1994

Influence of mouse genotype and bacterial virulence in the generation of interferon-gamma-producing cells during the early phase of Salmonella typhimurium infection.

Interferon-gamma (IFN-gamma) is known to play a major role in resistance to Salmonella typhimurium infection. In this study, the IFN-gamma production in spleens of mice infected with S. typhimurium was analysed at the single cell level using an ELISPOT method. The in vivo IFN-gamma production during the early phase of infection with virulent and avirulent S. typhimurium strains was examined in four mouse strains. Data show that infection with a virulent strain of S. typhimurium caused a much greater enhancement in the frequency of IFN-gamma-producing cells in innately resistant (ltyr) mice (CBA and DBA/2) than in susceptible (ltys) mice (C57BL/6 and BALB/c). In contrast, infection with an avirulent strain of S. typhimurium induced a clear increase in the number of IFN-gamma-producing cells in susceptible mice which was even greater than in resistant ones. These results indicate that both the host genetic background and bacterial virulence play a critical role in the regulation of IFN-gamma production during the early phase of S. typhimurium infection.

Animals↗
PubMed1993

Specific and natural antibody production during Salmonella typhimurium infection in genetically susceptible and resistant mice.

Genetically susceptible (C57BL/6) and resistant (CBA) mice were infected with an avirulent strain of Salmonella typhimurium and studied over a 35-day period for the production of antibodies directed against bacterial antigens including lipopolysaccharide (LPS) (specific antibodies) and antibodies directed against self antigens [natural antibodies (NAb)]. Antibodies directed against LPS and self antigens were detected by enzyme immunoassay (EIA) and those directed against other bacterial antigens by immunoblotting. We found that serum natural antibody titres in C57BL/6 and CBA mice were similar and correlated with the bacterial load in the spleen and liver. In C57BL/6 mice, anti-LPS antibodies remained polyreactive and of the IgM isotype. In contrast, CBA mice, after an early increase in polyreactive IgM anti-LPS antibodies, mounted a specific anti-LPS IgG antibody response. The immunoblotting results demonstrated that the IgM polyreactive antibodies in the resistant and susceptible mice recognized bacterial antigens of different molecular weights and that CBA, but not C57BL/6 mice, were able to produce IgG antibodies recognizing bacterial components. Our results suggest that the synthesis of antibodies directed against bacterial antigens and natural antibodies follow, at least partially, distinct pathways, but they do not allow us to determine whether these two antibody populations are produced by the same or distinct B-cell subpopulations.

Animals↗
PubMed1992

Role of gamma interferon and tumor necrosis factor alpha in resistance to Salmonella typhimurium infection.

In mice infected with a sublethal dose of Salmonella typhimurium, the injection of an anti-gamma interferon (IFN-gamma) monoclonal antibody increased bacterial proliferation in the spleen and led to death on day 7 or 8. Depletion of both CD4+ and CD8+ T cells with monoclonal antibodies in vivo had a much less marked effect during the first week of infection than the administration of anti-IFN-gamma antibodies, suggesting that cells other than T lymphocytes participate in the production of IFN-gamma at this time. Administration of anti-tumor necrosis factor alpha (TNF-alpha) antibodies to mice infected with a sublethal dose of S. typhimurium induced the same effect as anti-IFN-gamma antibodies, while the administration of both antibodies resulted in a synergistic interaction. When mice were infected with an avirulent strain of S. typhimurium and challenged on day 7 either with a virulent strain of S. typhimurium or with Listeria monocytogenes, their resistance to reinfection was slightly depressed by anti-IFN-gamma or anti-TNF-alpha antibodies given 1 day before challenge and much more strongly depressed by the simultaneous administration of both antibodies. Taken together, these results indicate that IFN-gamma and TNF-alpha play an essential role in acquired resistance during the early phase of S. typhimurium infection.

Animals↗
PubMed1992

Role of T-lymphocyte subsets in Rhodococcus equi infection.

Rhodococcus equi, a facultative intracellular gram-positive bacterium, can induce life-threatening infections in immunocompromised patients, especially those with AIDS. We have studied the mechanism of acquired immunity to this pathogen in a murine model. Protective immunity was induced by live but not killed bacteria. Adoptive transfer of resistance was obtained with spleen cells but not immune serum from mice immunized intravenously 30 days earlier with live bacteria. In normal mice, an intravenous challenge of 5 x 10(6) CFU of R. equi was cleared from the spleen, liver, and lungs within 3 weeks, whereas athymic nude mice were unable to clear the bacteria. In vivo depletion with monoclonal antibodies showed that both CD4+ and CD8+ T-cell subsets participate in the clearance of bacteria and that CD8+ T cells play the major role.

Actinomycetales Infections↗
PubMed1990

Role of CD4+ T cells and T-independent mechanisms in acquired resistance to Salmonella typhimurium infection.

Two aspects of acquired resistance to Salmonella typhimurium infection in BALB/c mice, i.e., the ability to clear the primary inoculum from the spleen and resistance to a secondary challenge, were studied with the use of mAb against T cell subsets. The ability to clear a temperature-sensitive mutant of S. typhimurium from the spleen (assessed at day 21) was abrogated by in vivo treatment with anti-CD4 mAb. Accelerated bacterial clearance could be adoptively transferred into naive mice. In vitro depletion experiments also showed the role of CD4+ T cells in this phenomenon. Depletion of CD8+ T cells had only a marginal effect. Resistance to reinfection in the late phase of the primary infection (day 50) was markedly depressed by in vivo treatment with anti-CD4 mAb, whereas this was not the case during the early phase (day 14). Furthermore, during the early phase of infection athymic nude mice showed increased nonspecific resistance to reinfection. Taken together these results suggest that T-independent mechanisms play a major role in acquired resistance during the early phase of infection.

Animals↗
PubMed1989

Suppression of primary antibody response in genetically susceptible mice infected with Salmonella typhimurium: restoration by catalase.

Susceptible C57BL/6 mice infected with a temperature-sensitive mutant of Salmonella typhimurium exhibited a marked depression of in vivo and in vitro primary antibody response to sheep erythrocytes which persisted for several weeks. The antibody response to a T-independent antigen (TNP-polyacrylamide) was also depressed. Cell-mixing experiments indicated that spleen cells from infected animals contained adherent suppressor cells and that the functional activity of T and B cells was unaffected. The antibody response of spleen cells from infected mice was restored by the addition of catalase, suggesting that hydrogen peroxide is involved in the mechanism of suppression.

Animals↗
PubMed1988

Genetic control of Salmonella typhimurium-induced depression of delayed-type hypersensitivity to sheep erythrocytes in mice.

Infection of mice with a temperature-sensitive mutant of Salmonella typhimurium C5TS allowed the survival of genetically susceptible mice. The ability to mount a delayed-type hypersensitivity (DTH) response to sheep erythrocytes during infection with C5TS was studied in various inbred mouse strains, recombinant inbred strains derived from C57BL/6 (susceptible) and A/J (resistant) mice, and C3H congenic mice. Suppression of the DTH response to sheep erythrocytes was found in mice that carried the Itys allele, the H-2b haplotype, or both. These genes are known to increase susceptibility to S. typhimurium infection. In contrast, no DTH response suppression was observed in mouse strains that carried other genes that increased susceptibility to S. typhimurium, e.g., DBA/2 and C3H/HeJ. Apart from a transient suppression in A/J mice, the DTH responses of resistant mice (A/J and CBA) were normal or increased. The DTH response to sheep erythrocytes could be restored in immunodepressed mice by increasing the immunizing dose, suggesting the possible role of activated macrophages in depression of the DTH response.

Animals↗
PubMed1988

Role of H-2 and non-H-2 genes in control of bacterial clearance from the spleen in Salmonella typhimurium-infected mice.

The ability of mice to clear Salmonella typhimurium from their spleens in the late phase of infection was studied after inoculation with a temperature-sensitive mutant. Clearance of bacteria was delayed in C57BL/6 mice compared with BALB/c, C3H/HeJ, DBA/2, A/J, and CBA mice. The responses of F1 hybrids, backcrosses, and recombinant inbred strains derived from C57BL/6 and BALB/c (both Itys) and of H-2 congenic mice were analyzed. The results showed that the low rate of bacterial clearance was recessive, that the rate of clearance was under polygenic control, and that an H-2-linked gene(s) plays a major role. Among H-2 congenic mice with a C57BL/10 background, three phenotypes of bacterial clearance could be distinguished: high (H-2j, H-2q, and H-2u), intermediate (H-2d, H-2f, H-2k, H-2p, H-2r, H-2s, and H-2v), and low (H-2b) rates. The effect of the H-2 complex was apparent with different genetic backgrounds (Itys and Ityr). In recombinant inbred strains derived from C57BL/6 (Itys) and A/J (Ityr) mice, the effect of the H-2b haplotype on bacterial clearance appeared to be fully expressed only in strains carrying the Itys allele.

Alleles↗
PubMed1987

[Comparative efficacy of ampicillin, chloramphenicol, cefotaxime, ceftriaxone and pefloxacin in experimental Salmonella typhimurium infection].

The efficacies of various antibiotics were compared in Salmonella typhimurium infection in mice. Treatment began 24 h after challenge. Antibiotics were given subcutaneously every 12 or 24 h in the following daily doses: 200 mg/kg for ampicillin, 100 mg/kg for chloramphenicol, cefotaxime and ceftriaxone, 50 mg/kg for pefloxacin. The number of bacteria in the spleens was determined after 3 and 7 days of treatment. In animals treated with ceftriaxone or pefloxacin the mean number of bacteria per spleen was from one to two log10 lower than in animals treated with other antibiotics. Similar results were obtained in genetically susceptible or resistant mice. The MIC being similar for cefotaxime, ceftriaxone and pefloxacin, the better in vivo activity of the two latter drugs appears to be related to their pharmacokinetic properties.

Ampicillin↗
PubMed1986

Release of a cytotoxic factor by macrophages stimulated with adjuvant-active peptidoglycans.

Bacterial peptidoglycans (PG) possess various immunomodulating activities, including the ability to inhibit the growth of some experimental tumors. We report here that PG induce the release by mouse (DBA/2 and C3H/HeJ) peritoneal macrophages of a cytotoxic factor (CF) that is active on L-929 cells and a 3-methylcholanthrene-induced tumor cell line but inactive on normal fibroblasts. Only the adjuvant-active PG (extracted from Bacillus megaterium and Staphylococcus aureus) were good inducers of the CF, whereas the adjuvant inactive PG (extracted from Micrococcus lysodeikticus and Corynebacterium poinsettiae) exhibited only weak activity. The CF was released within 2 hours of contact with PG either in serum-free or serum-containing media. The CF was inhibited neither by serum nor by the protease inhibitors that have been tested. It was stable for 30 minutes at 56 degrees C but inactivated after being heated for 10 minutes at 80 degrees C. After gel filtration, a single peak of activity at 80-90 kilodaltons was found. Chromatofocusing showed that the isoelectric point of the CF was 4.8.

Adjuvants, Immunologic↗