Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LISTERIA INFECTIONS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources
PubMed2000

MHC class Ib-restricted CTL provide protection against primary and secondary Listeria monocytogenes infection.

Infection of B6 mice with the intracellular pathogen Listeria monocytogenes (LM) results in the activation of CD8(+) T cells that respond to Ag presented by both MHC class Ia and class Ib molecules. Enzyme-linked immunospot analysis reveals that these CTL populations expand and contract at different times following a primary sublethal LM infection. Between days 4 and 6 postinfection, class Ib-restricted CTL exhibit a rapid proliferative response that is primarily H2-M3 restricted. The peak response of class Ia-restricted CD8(+) T cells occurs a few days later, after the majority of bacteria have been cleared. Although class Ia-restricted CTL exhibit a vigorous recall response to secondary LM infection, we observe limited expansion of class Ib-restricted memory CTL, even in MHC class Ia-deficient mice (B6.K(b-/-)D(b-/-)). Despite this lack of enhanced expansion in vivo, class Ib-restricted memory CTL retain the ability to proliferate and expand when provided with Ag in vitro. Furthermore, we demonstrate that in vivo depletion of CD8(+) T cells in LM-immune B6.K(b-/-)D(b-/-) mice severely impairs memory protection. Together, these data demonstrate that class Ib-restricted CTL play an important role in clearing a primary LM infection and generate a memory population capable of providing significant protection against subsequent infection.

Animals↗
PubMed1981

[Immunostimulating properties of an extract isolated from Aloe vahombe. 2. Protection in mice by fraction F1 against infections by Listeria monocytogenes, Yersinia pestis, Candida albicans and Plasmodium berghei].

A partially purified extract of leaves of Aloe vahombe, a plant endemic in the south of Madagascar, administered intravenously to mice, protects them against infection of bacteria (Listeria monocytogenes, Yersinia pestis), parasites (Plasmodium berghei) and fungus (Candida albicans). The protective fraction must be administered two days before inoculation of the pathogenic agent. These results significantly confirm those we obtained in earlier study on mice infection by Klebsiella pneumoniae. Currently we are testing the protective action of the purified extract on the experimental development of sarcomas, and we are in the process of analysing the mode of action of this non specific immunostimulant.

Adjuvants, Immunologic↗
PubMed1997

Comparison of inducible nitric oxide synthase expression in the brains of Listeria monocytogenes-infected cattle, sheep, and goats and in macrophages stimulated in vitro.

The expression of inducible nitric oxide synthase (iNOS) was studied in the brains of cattle, sheep, and goat that succumbed to a natural infection with Listeria monocytogenes. The lesions in infected brains are characterized by microabscesses, perivascular cuffs, gliosis, glial nodules, and large areas of malacia. Using immunocytochemistry, we detected bacteria in microabscesses, particularly in sheep and goats, and in areas without signs of inflammation, but not in perivascular infiltrates. iNOS was expressed by macrophage (Mphi)-type cells of microabscesses and glial nodules but rarely by Mphi in areas of malacia, as determined by immunohistochemistry with iNOS-specific antibodies. iNOS was not detected in perivascular cuffs. Major histocompatibility complex class II molecules (MHC-II), another marker of cell activation, showed a different pattern of distribution. Perivascular cuffs contained high numbers of MHC-II-positive cells, including some with Mphi characteristics. Microabscesses in sheep and goats showed low expression of MHC-II, particularly in iNOS-expressing cells. In cattle, the expression of markers for activated or recruited phagocytes, the calcium-binding proteins S100A8 and S100A9 (formerly called MRP-8 and MRP-14, respectively), was largely restricted to cells showing weak or undetectable iNOS expression; iNOS-positive Mphi showed a low expression of S100A8 and S100A9. Thus, iNOS is expressed by a restricted subset of Mphi in listeric encephalitis. In cultured sheep and goat Mphi, a low proportion of cells expressed iNOS upon activation by L. monocytogenes and gamma interferon, resulting in nitrite generation at least 1 order of magnitude lower than that in similarly treated cattle Mphi. Since these species differences were much less obvious in vivo, it appears that the well-known species variation in iNOS expression by Mphi could reflect an in vitro phenomenon.

Animals↗
PubMed1984

Listeria monocytogenes infections in Canada.

Since its first isolation by Murray in 1926 Listeria monocytogenes has become recognized as a significant pathogen occurring worldwide and involving a wide range of wild and domestic animals including man. The first confirmed human listeriosis case in Canada was published by Stoot in 1951. A later survey based on records maintained at the Laboratory Centre for Disease Control, Ottawa showed 101 cases detected over a 21 year period in nine provinces. The overall mortality was 30%. The most frequently isolated serotype was 4b followed by 1 and 1b. Prior to the Nova Scotia epidemic (41 cases) of 1981, fewer than 15 cases per annum had been diagnosed based on hospital discharge records. The Nova Scotia epidemic was unique in that the source and mode of transmission of the organism were determined. Sixty-three strains isolated from this outbreak were typed, and with the exception of one 1a strain, were identified as 4b. These were subsequently classified mainly as phage type 00 042 0000 and 00 002 0000. Listeriosis appears to be a common infection in the animal population in Canada primarily in cattle, sheep, chinchillas, chickens and goats. Outbreaks have been described in rabbits, goats, and chinchillas. Chinchilla farms were affected in one outbreak (serotype 1) in Nova Scotia which was attributed to feeding a new batch of meal containing beet pulp. Many aspects of the epidemiology of listeriosis are obscure. A cycle involving contaminated soil and consumption of raw vegetables has been confirmed as the cause of the Nova Scotia epidemic and could explain a proportion of the sporadic cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2005

CpG-activated Thy1.2+ dendritic cells protect against lethal Listeria monocytogenes infection.

Synthetic oligodeoxynucleotides containing CpG motifs (CpG ODN) activate the innate immune system by interacting with Toll-like receptor 9. The resultant immune response increases host resistance to infection by a variety of pathogenic microorganisms, including Listeria monocytogenes. There is a considerable interest in harnessing the immunoprotective properties of CpG ODN, yet little is known of the cell phenotype(s) responsible for mediating this protection. This work demonstrates that treatment of mice with CpG ODN increases the number of Thy1.2+, CD11c+ dendritic cells (Thy1.2+ DC) in the spleen, which are both necessary and sufficient for transferring resistance to infection from CpG-treated donors to naive recipients. These CpG-activated Thy1.2+ DC are distinct from conventional (CD11c(hi), Thy1.2-) or plasmacytoid DC (mPDCA+), and secrete IFN-gamma that contributes to protection. These findings suggest that a novel Thy1.2+ DC subset plays a critical role in mediating the immunoprotective activity of CpG DNA.

Adoptive Transfer↗
PubMed1975

Blastogenesis as an in vitro correlate of delayed hypersensitivity in guinea pigs infected with Listeria monocytogenes.

Randomly bred guinea pigs of both sexes were injected intracardially with one-half a 50% lethal dose of Listeria monocytogenes. When these animals were skin tested with 30 mug of a water-soluble extract of sonically disrupted Listeria, animals had uniformly detectable levels of delayed-type hypersensitivity (DTH) 6 days after infection. Histological examination of skin test reaction sites, after fixation in Helly fixative and Giemsa staining, revealed a classical tuberculin-type infiltrate consisting primarily of mononuclear cells with few polymorphonuclear cells. Many of the small vessels showed perivascular cuffing. When purified peritoneal exudate lymphocytes from these animals were cultured in vitro in the presence of various concentrations of Listeria antigen, it was fount that the optimal antigenic dose for specific antigen-induced incorporation of [3H]thymidine varied for individual animals. In contrast to the early onset of uniformly detectable levels of in vivo DTH, in vitro lymphocyte blastogenesis was not uniformly demonstrable until 14 days postinfection and remained highly significant on days 21, 28, and 84 postinfection. At 7 days postinfection, lymphocytes from 7 of 17 animals were capable of undergoing sifnificant blastogenesis. The Listeria antigen preparation was not mitogenic for peritoneal exudate lymphocytes from normal animals. It was found that no direct correlation exists between the in vivo levels of DTH and in vitro blastogenesis. Cell donors showing significant in vitro blastogenesis nevertheless were also skin test positive for most animals tested. Humoral antibody was found to play no significant role in the immune response of guinea pigs to a primary infection with Listeria monocytogenes.

Animals↗
PubMed1989

The treatment of Listeria monocytogenes infections in the central nervous system.

Fifty-four cases of Listeria monocytogenes meningitis and meningoencephalitis occurred in Denmark between 1981 and 1986. The aim of the present study was to consider the antibiotic treatment of these patients, 33 males and 21 females aged from 16 months to 91 years: average (AV) 54 years. One or more predisposing factors (PF) were found in 30 patients (55%): steroid treatment (15), cancer (12), alcoholism and/or cirrhosis (10), diabetes mellitus (5), and renal allograft (2). Follow-up varied from 3 months to 5 years. Ampicillin (AMP) was used as the only antibiotic in 14 patients, and with an aminoglycoside (AMI) in 38 but AMI was withdrawn within 24-48 h in 14. High doses of AMP were used (AV 16 g/day) generally for two weeks (AV 11 days), but AMI was usually withdrawn in the first week (AV 5 days). The mortality rate (MR) was 39% and varied greatly between previously healthy patients (PHP) and those with one or more PF: only 2 out of 24 PHP died, both admitted to hospital with respiratory insufficiency and shock. No significant differences between survivors and non-survivors were observed either in the doses, duration and administration of AMP, or use of AMI, although a higher number of PF was found in the non-survivors. Relapse occurred in at least 3 immuno-compromised patients. Sequelae were reported in 9 patients. Death occurred in 6 within 24-48 h of admission. Delayed diagnosis and treatment together with the underlying disease seemed responsible for the high MR. More effective treatments in immunocompromised patients should be tried.

Adolescent↗
PubMed1975

Effect of Corynebacterium parvum on the course of a Listeria monocytogenes infection in normal and congenitally athymic (nude) mice.

Spleen counts of Listeria monocytogenes in normal mice challenged with various numbers of organisms were generally lower in mice injected 3 days previously with killed Corynebacterium parvum. This increased resistance was unexpected since C. parvum generally inhibits T cell-mediated immunity, the functional immunity against Listeria being T cell-dependent. The inhibitory effect on T cells seemed to be compensated by the stimulatory effect of C. parvum on macrophages. Therefore, the experiments were repeated in congenitally athymic (nude) mice (B10LP) lacking functional T cells. C. parvum pretreatment of nu/nu mice prolonged the time between challenge and death, the number of survivors in the pretreated and non-treated mice being approximately equal. It was concluded that C. parvum exerted a stimulatory effect on macrophages resulting in a higher resistance against Listeria.

Animals↗
PubMed2006

[Zoonotic importance of selected species of Gram-positive bacteria.].

Zoonoses continue to play a signicant role in both human and veterinary medicine. Their eradication is difficult and some authors are convinced of their growing importance. Among the pathogens of infectious diseases transmissible from animals to man are several gram-positive bacteria. The authors focus on three agents that present a risk in three different areas-alimentary infections (Listeria monocytogenes), professional infections (Streptococcus suis) and infections of breeders of so-called pet animals (Staphylococcus aureus and Staphylococcus intermedius). The paper analyses the risk of human infections from animal sources and briefly informs on the present incidence of pathogens in animals and/or raw materials of animal origin in the catchment area of the State Veterinary Institute in Olomouc, Moravia.

Animals↗
PubMed1988

Immunomodulatory effects of staphylococcal lipoteichoic acid in early Listeria monocytogenes infection in Balb/c-mice.

Balb/c-mice were intravenously infected with 5 X 10(4) viable cells of Listeria monocytogenes SLCC 4013. Liver, lung and spleen of the animals showed heavy organ colonization 48 h after infection. Pretreatment of experimental animals with staphylococcal lipoteichoic acid (LTA; 2 mg i.p. 7 and 3 days before challenge) significantly reduced the bacterial count in these organs. In vitro, peritoneal macrophages from LTA-treated mice significantly reduced listerial viability as compared to control cells (p less than 0.0025). In vitro, exposure of macrophages from non-treated animals to LTA did not influence their bacterial killing ability.

Animals↗
PubMed1999

The protective role of T-cell receptor Vgamma1+ T cells in primary infection with Listeria monocytogenes.

We have previously reported that the T-cell receptor (TCR) gamma delta+ T cells increase in mice infected with an intracellular bacteria Listeria monocytogenes, and the cells predominantly express Vdelta6 and Vgamma1 genes. In this study, we used a monoclonal antibody (mAb) specific to TCR Vgamma1 to estimate the frequency of Vgamma1+ T cells and we discuss their significance in protection against L. monocytogenes. The spleen, liver and peritoneal exudate cells from mice intraperitoneally infected with L. monocytogenes were analysed by flow cytometry. In all the organs investigated, Vgamma1+ cells increased predominantly among TCR gamma delta+ T cells at an early phase (day 5-7) of the infection. To elucidate the significance of the Vgamma1+ T cells in the protection against L. monocytogenes, mice were depleted of TCR Vgamma1+ gamma delta T cells or all TCR gamma delta+ T cells by intraperitoneal inoculation of anti-Vgamma1 mAb or anti-pan TCR gamma delta mAb, respectively, before infection with L. monocytogenes. The bacterial growth in the spleen and the liver examined on day 5 after the infection increased significantly by the depletion of TCR Vgamma1+ T cells. The numbers of L. monocytogenes in TCR Vgamma1+ T-cell-depleted mice were nearly the same as in mice depleted of all TCR gamma delta+ T cells. These results demonstrated that Vgamma1+ T cells are the predominant population of gamma delta T cells in protection against L. monocytogenes at the early phase of the primary infection.

Animals↗
PubMed2003

Role of CD4 T cell help and costimulation in CD8 T cell responses during Listeria monocytogenes infection.

CD4 T cells are known to assist the CD8 T cell response by activating APC via CD40-CD40 ligand (L) interactions. However, recent data have shown that bacterial products can directly activate APC through Toll-like receptors, resulting in up-regulation of costimulatory molecules necessary for the efficient priming of naive T cells. It remains unclear what role CD4 T cell help and various costimulation pathways play in the development of CD8 T cell responses during bacterial infection. In this study, we examined these questions using an intracellular bacterium, Listeria monocytogenes, as a model of infection. In CD4 T cell-depleted, CD4(-/-), and MHC class II(-/-) mice, L. monocytogenes infection induced CD8 T cell activation and primed epitope-specific CD8 T cells to levels commensurate with those in normal C57BL/6 mice. Furthermore, these epitope-specific CD8 T cells established long-term memory in CD4(-/-) mice that was capable of mounting a protective recall response. In vitro analysis showed that L. monocytogenes directly stimulated the activation and maturation of murine dendritic cells. The CD8 T cell response to L. monocytogenes was normal in CD40L(-/-) mice but defective in CD28(-/-) and CD137L(-/-) mice. These data show that in situations where infectious agents or immunogens can directly activate APC, CD8 T cell responses are less dependent on CD4 T cell help via the CD40-CD40L pathway but involve costimulation through CD137-CD137L and B7-CD28 interactions.

4-1BB Ligand↗
PubMed1984

Modulation of natural killer activity in mice following infection with Listeria monocytogenes.

Mice that received a sublethal, intraperitoneal dose of viable Listeria monocytogenes, virulent strain 10403, exhibited a systemic increase in natural killer (NK) activity. The kinetics of the response differed with respect to the various effector cell populations analyzed. Resident peritoneal cells and peripheral blood leukocytes demonstrated high NK activity on Days 3, 7, and 10. Peak spleen and bone marrow NK activity was observed on Day 3, returning to normal levels by Day 7. In contrast, peritoneal exudate cells, elicited with proteose peptone, expressed enhanced NK activity for 60 days following infection with viable Listeria. Augmented NK activity was detected with all cell types as early as 12 hr after infection. The intraperitoneal injection of nonviable antigenic preparations derived from L. monocytogenes, strain 10403, resulted in the enhancement of peritoneal and splenic NK activity. In contrast, mice that received an intraperitoneal injection of avirulent Listeria, strain 19113, failed to express enhanced levels of NK activity. The genetic trait of anti-listerial resistance which is associated with non-H-2 linked genes was of no importance with respect to enhanced NK activity. Listeria-resistant C57BL/6J and Listeria-susceptible DBA/2J mice both produced systemic augmentation of NK activity following infection. NK activity was not abrogated by macrophage depletion or by treatment with anti-Thy 1.2 serum plus complement. These results confirm the potent immunostimulatory capacity of virulent Listeria for NK activity and provide further insight into the kinetics of this response in various lymphoid compartments. The protracted augmentation of NK activity of elicited peritoneal exudate cells as compared to nonelicited peritoneal cells in Listeria-primed mice suggests that the influx of inflammatory cells may provide NK-enriched and/or accessory populations for immunopotentiation of NK activity in inflammatory sites.

Animals↗
PubMed1991

Role of listeriolysin-O (LLO) in the T lymphocyte response to infection with Listeria monocytogenes. Identification of T cell epitopes of LLO.

Using a murine model, we investigated the role of the bacterial exotoxin listeriolysin O (LLO) in cellular immunity to Listeria monocytogenes. A correlation between LLO production by infecting bacteria and generation of protective immunity to virulent LLO-producing bacteria was noted. Using isogeneic hemolysin (Hly+ or Hly-) strains of L. monocytogenes, we demonstrated that LLO production by infecting bacteria is required to elicit T cells reactive both to bacteria-associated Ag and to the secreted LLO molecule as measured by IL-2 production in vitro. Distinct sets of T cells specific for largely nonoverlapping pools of antigenic determinants represented by LLO and cell-associated Ag (heat-killed L. monocytogenes) are generated after infection. We have used models for prediction of T cell epitopes based on primary structure of LLO, and synthetic amphipathic LLO peptides were evaluated as Ag in vitro or as immunogenes in vivo. Infection of several strains of mice (H-2k and H-2d) with LLO-producing L. monocytogenes resulted in the generation of T cells that could respond consistently to two peptides, LLO 215-234 and LLO 354-371. Mouse strains lacking expression of I-E molecules (e.g., B10.A(4R) and C57BL/6) responded to LLO but not to the peptides tested. With C3HeB/FeJ mice, antibodies to I-Ek blocked the presentation of LLO 215-234. The importance of the N-terminal portion of LLO 215-234 was evidenced by the drastic reduction in antigenic activity of truncated peptides (e.g., LLO 221-234 and LLO 224-234). LLO 215-234, the strongest and most consistent activator of T cells from L. monocytogenes-immune mice, fit well some models for antigenic peptides in several ways. It could be predicted to form an amphipathic alpha-helix, it contained multiple "Rothbard motifs" (charged residue or glycine, two or three hydrophobic amino acids and then a glycine or polar residue), it had a net charge of +2, and it contained the correct spacing of amino acids (five to six residues between a hydrophobic and basic amino acid) that is characteristic of I-Ek-binding peptides. Immunization with 8 of 10 synthetic LLO peptides generated T cells that recognized the immunizing peptide in vitro, but such T cells were only poorly reactive with LLO. Our results indicate that LLO is an important target Ag for stimulation of CD4+ L. monocytogenes-specific T cells, and that LLO 215-234 is antigenically dominant in C3HeB/FeJ mice.

Animals↗
PubMed1988

Kinetics of interleukin-1 production by macrophages during infection with Listeria monocytogenes.

Production of interleukin-1 (IL-1) by peritoneal macrophages from mice inoculated intravenously with Listeria monocytogenes was measured at increasing intervals of infection. IL-1 activity in the 24 h macrophage supernatants was determined by using the thymocyte PHA co-mitogenesis assay. IL-1 production increased as the infection progressed, reached a peak on the 9th or 10th day and then declined progressively to approach normal values by the 20th day. Our data on the kinetics of IL-1 levels during an acute infection with L.monocytogenes are discussed in relationship to the development of cell-mediated immunity and its regulation by macrophages.

Animals↗
PubMed1992

Effects of administration of murine recombinant IL-4 on the resistance of mice to Listeria monocytogenes infection.

Mice given recombinant murine interleukin-4 as a single i.v. bolus concomitant with a Listeria monocytogenes challenge did not display increased anti-listeria resistance. Under certain conditions, IL-4 administration slightly increased the bacterial burdens in the spleens and livers of infected mice. This finding is consistent with previous reports that endogenous IL-4, or transfer of IL-4 producing TH2 cells, can be detrimental to host defense against microbial infection.

Animals↗
PubMed1997

[A case report of Listeria monocytogenes infection in a patient with AIDS. Efficacy of treatment with cotrimoxazole associated with rHuG-CSF (filgrastim)].

Listeriosis is an emerging opportunistic infection in the immunocompromised host. A case of sepsis due to Listeria monocytogenes in a patient with advanced HIV infection and severe neutropenia, treated for an underlying non-Hodgkin's lymphoma, is described. Therapy with cotrimoxazole associated with rHuG-CSF (filgrastim) led to a rapidly favourable clinical and microbiological outcome, and to the correction of concurrent neutropenia. The case report is discussed according to a literature review of all cases of listeriosis reported until now in the setting of HIV infection and AIDS. In particular, the role of both cotrimoxazole and rHuG-CSF adjunct in the treatment of listeriosis in the immunocompromised patient is focused.

English Abstract↗