Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In patients with cystic fibrosis (CF), respiratory tract infections caused by Staphylococcus aureus and Haemophilus influenzae are followed by Pseudomonas aeruginosa with increasing age. Chronic endobronchial lung infection with P. aeruginosa is the leading cause of morbidity and mortality. In Danish CF patients we noted that both onset of initial colonization and chronic lung infection with P. aeruginosa peaked during the winter months which is the season for respiratory virus infections. Virus may therefore pave the way for P. aeruginosa. We established a chronic P. aeruginosa lung infection in rats by embedding mucoid bacteria in seaweed alginate and installing the beads intratracheally into the lower part of the left lung. Although the rats did not suffer from CF, the antibody responses and the pathologic changes of the lungs mimicked the findings in CF patients. By using this model in normal and athymic rats we showed that the T-cell response during the "natural" course of the infection played no major role. In a model of acute P. aeruginosa pneumonia we found that the macroscopic inflammatory response of the lungs was immense and that the natural capacity to clear P. aeruginosa was very efficient and could not be improved by immunization, although high serum levels of IgM, IgG and IgA antibodies to P. aeruginosa alginate, LPS, exotoxin A and sonicate were induced. We developed a method for collecting and measuring IgA in saliva and noted that mucosal IgA antibodies were induced by vaccination; they did not significantly prevent inflammation, however. In the chronic rat model we succeeded to improve the survival significantly and to change the inflammatory response subsequent to vaccination from an acute type inflammation dominated by polymorphonuclear leukocytes (PMNs) as in CF patients to a chronic type inflammation dominated by mononuclear leukocytes. Furthermore, we found that rats immunized with an alginate containing vaccine had a significantly earlier cellular shift to a chronic type inflammation as well as a significant reduction in the severity of the macroscopic inflammation compared to two other vaccine groups and to nonimmunized controls. Similar results were obtained in rats treated with the TH1 cytokine, interferon-gamma (IFN-gamma). Several authors have shown that the lung tissue damage during chronic infection in CF patients is caused by a type III hypersensitivity reaction leading to release of elastase by PMNs surrounding the bacterial microcolonies. The cellular shift we have induced by vaccination and by IFN-gamma treatment therefore offers a possible new strategy for improving the clinical course in chronically infected CF patients.
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PMID:Potential of preventing Pseudomonas aeruginosa lung infections in cystic fibrosis patients: experimental studies in animals. 894 52

Using in situ hybridization with radiolabelled oligonucleotide probes, we studied the mRNA expression of IL-1beta, IL-4, IL-6, IL-10, IL-12, tumour necrosis factor-alpha (TNF-alpha), TNF-beta, interferon-gamma (IFN-gamma), and transforming growth factor-beta (TGF-beta) in the brain during the lethal course of experimental meningitis in a rat model inoculated intracisternally with Haemophilus influenzae type b (Hib) or Streptococcus pneumoniae and in uninfected control rats inoculated with the same volume of PBS. The production of IL-1beta, IL-4, IL-6 and IFN-gamma was also evaluated by immunohistochemistry. In the brain of Hib-inoculated rats, there was marked mRNA expression of IL-1beta, IL-6, TNF-alpha, IL-12 and IFN-gamma. IL-1beta, IL-6 and TNF-alpha were up-regulated throughout the observation period at 2, 8 and 18 h post-inoculation (p.i.), with similar patterns of induction. The Th1 cytokines IFN-gamma and TNF-beta were up-regulated within 8 h p.i. IL-10 and TGF-beta were down-regulated at 18 h p.i., while IL-4 was not detected. In contrast, the brain of S. pneumoniae-inoculated rats showed lower levels of IL-1beta, IL-6 and TNF-alpha, but higher levels of TNF-beta and detectable mRNA expression of IL-4 when compared with Hib-inoculated rats. IL-12, IFN-gamma, IL-10 and TGF-beta exhibited similar patterns of induction in the brains of Hib- and S. pneumoniae-inoculated rats. At 18 h p.i., immunohistochemistry showed similar patterns of IL-1beta, IL-4, IL-6 and IFN-gamma as mRNA expression in the brains of Hib- and S. pneumoniae-inoculated rats. The differences of cytokine profiles induced by the two bacterial strains may imply that different immunomodulating approaches should be considered, depending on etiology.
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PMID:Haemophilus influenzae and Streptococcus pneumoniae induce different intracerebral mRNA cytokine patterns during the course of experimental bacterial meningitis. 927 17

We have recently described the induction of anti-cytokine autoantibodies (Aabs) in the serum as a novel mechanism for cytokine regulation during bacterial infections. Here we use the infant rat-model of Haemophilus influenzae type b (Hib) meningitis to examine the induction of five potentially important cytokines and their autoantibody responses in the CSF. Protein levels of the cytokines interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), IL-4 and IL-10 were detected at day 3 post-inoculation (p.i.) with maximum induction at day 8. Thereafter, these levels of cytokines had become undetectable. Increased Aab titres to these cytokines, except IL-4, were registered with peak levels between days 7 and 9. Upon re-inoculation with Hib at day 30, regeneration of Aabs was recorded 7 days later (i.e. at day 37). To control the specificity of these Aabs, preincubation of the CSF with a cytokine inhibited the binding effects of that particular cytokine, but not those of any other cytokine. Aabs dose-dependently inhibited IFN-gamma-induced MHC expression by peritoneal macrophages and TNF-alpha-mediated L929 cytotoxicity. Our data demonstrate for the first time the existence of the anti-cytokine antibodies in the CSF of the meningitis Hib model. Furthermore, the data present a role for the Aabs in cytokine regulation, which is consistent with the previously demonstrated effects of the Aabs in the serum.
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PMID:Induction of cytokines and anti-cytokine autoantibodies in cerebrospinal fluid (CSF) during experimental bacterial meningitis. 984 49

The mechanisms used by Haemophilus somnus to survive and multiply within bovine mononuclear phagocytes are not fully understood. In order to study the interaction between bovine mononuclear phagocytes and H. somnus, a colorimetric assay using 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenylItetrazolium bromide (MTT) was developed to assess the survival of H. somnus within cultured bovine blood monocytes (BBM). Using this system, it was found that H. somnus was able to survive within BMM in vitro, and the kinetics of its survival were similar to that seen in BBM isolated from experimentally infected cattle. Using ultrastructural studies, it was possible to demonstrate the survival of H. somnus in freshly isolated bovine mononuclear phagocytes in membrane-bound vacuoles. To determine if activation of macrophage function would result in elimination of intracellular H. somnus, BBM were treated with E. coli lipopolysaccharide (LPS) or recombinant bovine (rBo) cytokines, interferon-gamma (IFN-gamma), granulocyte macrophage colony stimulating factor (GM-CSF), tumour necrosis factor-alpha (TNF-alpha) or interleukin-1beta (IL-1beta). Treatment of BBM with rBoIFN-gamma, rBoGM-CSF or E. coli LPS resulted in decreased intracellular survival of H. somnus at 18 and 48 h, whereas BBM treated with rBoTNF-alpha or rBoIL-1beta had reduced intracellular survival of H. somnus only at 18 h. However, none of these treatments resulted in complete elimination of the intracellular bacteria. The ability of H. somnus to survive and multiply in both freshly isolated and cytokine-treated cultured BBM demonstrated the capability of H. somnus to escape from macrophage killing mechanisms. This capability may play a role in the dissemination of H. somnus infection in the body.
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PMID:Intracellular survival of Haemophilus somnus in bovine blood monocytes and alveolar macrophages. 987 52

To determine the efficacy of a mucosal vaccine against nontypeable Haemophilus influenzae (NTHi), mice were immunized nasally, orally, intratracheally, or intraperitoneally with NTHi antigen together with cholera toxin. Antigen-specific IgA antibody titers in nasal washes and the numbers of antigen-specific IgA-producing cells in nasal passages showed the greatest increases in mice immunized nasally. Cytokine analysis showed that interferon-gamma, interleukin (IL)-2, IL-5, IL-6, and IL-10 were induced by nasal immunization, suggesting that Th2- and Th1-type cells were generated. Furthermore, bacterial clearance of a homologous strain of NTHi from the nasal tract was significantly enhanced in the nasal immunization group. These findings suggest that nasal immunization is an effective vaccination regimen for the induction of antigen-specific mucosal immune responses, which reduce the colonization of NTHi in the nasal tract.
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PMID:Nasal immunization induces Haemophilus influenzae-specific Th1 and Th2 responses with mucosal IgA and systemic IgG antibodies for protective immunity. 1035 70

We have recently described an immunoregulatory mechanism involving release of neutralizing autoantibodies (Aab) to cytokines during bacterial infections. Intraperitoneal inoculation of Haemophilus influenzae type b (Hib) into Sprague-Dawley rats resulted in high levels of inflammatory mediators early after infection. Increased titers of cytokine Aab were observed, with a peak at day 7. We cloned Aab-producing B cells. Screening of the clones with five different cytokines resulted in detection of Aab-producing clones reactive with each cytokine. After repeated subcloning, monoclonal Aab (mAab) were selected and characterized for their specificity, isotypes, and affinities. To elucidate regulatory importance, mAab to interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) dose-dependently inhibited IFN-gamma-induced MHC expression by peritoneal macrophages and TNF-alpha-induced thymocyte proliferation, respectively. Fab fragments exhibited binding and neutralizing effects, confirming specificities. Cross-reactivity with other rat cytokines was excluded. Pools of clones containing several mAab to each cytokine were obtained and served as polyclonal Aab. The relative affinity of the Aab was determined and found to be of high index. The characterized Aab were tested in methodologic assays for cytokine detection, revealing that some Aab were useful in a cell release capturing (CRC) ELISA.
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PMID:A novel mechanism for cytokine regulation: screening, selection, and characterization of anticytokine monoclonal and polyclonal autoantibodies. 1038 55

It has been reported that intranasal immunization can induce mucosal immune responses. However, the efficacy of intranasal immunization on otitis media caused by non-typeable Haemophilus influenzae (NTHi) is not yet elucidated. Mice were intranasally, orally, intratracheally or intraperitoneally immunized with outer membrane protein (OMP) isolated from NTHi, and antigen-specific immune responses were determined by enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immuno-spot assay (ELISPOT). Cytokine production from splenic CD4+ T cells was examined by ELISA. Following the immunization, the clearance of NTHi from the nasal and nasopharyngeal cavity was examined. OMP-specific IgA antibody titers in nasal washes and the numbers of specific IgA-producing cells in nasal passages were significantly increased in intranasally immunized mice. Cytokine analysis showed that interferon-gamma (IFN-gamma) and interleukins IL-6 and IL-10 were predominantly produced from CD4+ T cells. The clearance of NTHi was significantly enhanced in the intranasal immunization group. Intranasal immunization is an effective vaccination regimen for the induction of OMP-specific mucosal immune responses.
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PMID:Effects of intranasal immunization on protective immunity against otitis media. 1057 10

Much evidence, both in vivo and in vitro, suggests that patients with IgA nephropathy (IgAN) have enhanced IgA production. We hypothesized that Haemophilus parainfluenzae (HP) in the tonsil plays an important role in the IgA production of IgAN patients. In this study, we focused on interferon-gamma (IFN-gamma) and IgA production by tonsillar mononuclear cells (TMC) in patients with IgAN. Tonsillectomies were performed in patients with IgAN and chronic tonsillitis (CT). The induction of IFN-gamma and IgA in vitro by TMC from IgAN patients was compared with that from CT patients. In addition, we investigated whether stimulation with the outer membranes of HP (OMHP) enhanced IFN-gamma and IgA induction by TMC from patients with IgAN. Spontaneous IFN-gamma production and spontaneous total IgA production by TMC were higher in IgAN patients than in those patients with CT (p < 0.05). IFN-gamma induction by OMHP stimulation was also higher in IgAN patients than in CT patients. The stimulation of OMHP enhanced HP-specific IgA in IgAN but had no influence on the production of IFN-gamma in patients with either IgAN or CT compared with spontaneous IFN-gamma production. IFN-gamma production was positively correlated with total IgA values in both IgAN and CT patients, but not with HP-specific IgA. These results suggest that increased IFN-gamma production in patients with IgAN is not associated with HP infection but may play a role in the pathogenesis of IgAN.
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PMID:Production of interferon-gamma by tonsillar mononuclear cells in IgA nephropathy patients. 1103 78

Haemophilus influenzae type b (Hib) capsular polysaccharide (PS) induces protective antibodies but is T independent and poorly immunogenic in infants. Conjugate vaccines of Hib PS linked to proteins, such as CRM(197), increase the PS antibody titer and elicit immunologic memory. To define the conjugate-induced memory T cell response, 19 adults were immunized with Hib-CRM(197), and antibody titers, carrier protein-specific CD4(+) T cell proliferation, and cytokine production were measured. Hib-CRM(197) induced PS and CRM(197) antibodies, vigorous T cell recall responses, and production of cytokines, including interleukin (IL)-2, IL-5, IL-10, and interferon-gamma. There was marked variability in PS antibody titer, despite consistent CRM(197)-specific recall responsiveness, which correlated with peak IgM and IgA PS antibody titers. Correlations were also found between IL-2 and IL-5 and IgA PS antibody levels. Hib-CRM(197) induced a rapid increase in CRM(197)-specific memory T cells and mixed Th1/Th2 cytokines, which may regulate the isotype and quantity of PS antibody.
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PMID:Immunization with Haemophilus influenzae type b-CRM(197) conjugate vaccine elicits a mixed Th1 and Th2 CD(4+) T cell cytokine response that correlates with the isotype of antipolysaccharide antibody. 1152 93

Progress in producing improved vaccines against bacterial diseases of cattle is limited by an incomplete understanding of the pathogenesis of these agents. Our group has been involved in investigations of two members of the family Pasteurellaceae, Mannheimia haemolytica and Haemophilus somnus, which illustrate some of the complexities that must be confronted. Susceptibility to M. haemolytica is greatly increased during active viral respiratory infection, resulting in rapid onset of a severe and even lethal pleuropneumonia. Despite years of investigation, understanding of the mechanisms underlying this viral-bacterial synergism is incomplete. We have investigated the hypothesis that active viral infection increases the susceptibility of bovine leukocytes to the M. haemolytica leukotoxin by increasing the expression of or activating the beta2 integrin CD11a/CD18 (LFA-1) on the leukocyte surface. In vitro exposure to proinflammatory cytokines (i.e. interleukin-1beta, tumor necrosis factor-alpha and interferon-gamma) increases LFA-1 expression on bovine leukocytes, which in turn correlates with increased binding and responsiveness to the leukotoxin. Alveolar macrophages and peripheral blood leukocytes from cattle with active bovine herpesvirus-1 (BVH-1) infection are more susceptible to the lethal effects of the leukotoxin ex vivo than leukocytes from uninfected cattle. Likewise, in vitro incubation of bovine leukocytes with bovine herpesvirus 1 (BHV-1) potentiates LFA-1 expression and makes the cells more responsive to leukotoxin. A striking characteristic of H. somnus infection is its propensity to cause vasculitis. We have shown that H. somnus and its lipo-oligosaccharide (LOS) trigger caspase activation and apoptosis in bovine endothelial cells in vitro. This effect is associated with the production of reactive oxygen and nitrogen intermediates, and is amplified in the presence of platelets. The adverse effects of H. somnus LOS are mediated in part by activation of endothelial cell purinergic receptors such as P2X7. Further dissection of the pathways that lead to endothelial cell damage in response to H. somnus might help in the development of new preventive or therapeutic regimens. A more thorough understanding of M. haemolytica and H. somnus virulence factors and their interactions with the host might identify new targets for prevention of bovine respiratory disease.
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PMID:Complexities of the pathogenesis of Mannheimia haemolytica and Haemophilus somnus infections: challenges and potential opportunities for prevention? 1598 39


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