Role of Type I Interferon during Bacterial Infection

Type 1 Interferons (T1 IFN) play a pivotal role in innate immune responses against viral infection. Recently, this anti-viral cytokines are shown to be induced during bacterial infections via activation of various pattern recognition receptors (PRRs) including Toll-like receptors, RIG-I-like receptors, or NOD-like receptors. Signaling mediators such as MyD88, TRIF, MAVS, STING, or RIP2 of the receptor signaling pathways are also involved in T1 IFN responses depending on the bacterial species and their ligands. However, role of T1 IFN in anti-bacterial immunity is still obscure and its effect on immunological pathogenesis during bacterial infection has been controversial. It has been reported that T1 IFN could provide protective effect on several bacterial infections but it also aggravates pathogenic situation during some intracellular pathogens or secondary bacterial infection after respiratory viral infection. Here, we summarize recent findings how T1 IFN is induced by various bacterial pathogens and discuss the potential effect of T1 IFN responses on immune responses against bacterial infection.

Molecular Characterization of sca Genes Found in Orientia tsutsugamushi Genome

Scrub typhus is an acute, febrile illness caused by Orientia tsutsugamushi infection and it is one of the main causes of acute febrile illness in the Asian-Pacific region. The incidence of scrub typhus has been significantly increased in Korea during last 10 years. Although early diagnosis and proper antibiotic treatment are important to prevent severe complications, the clinical discrimination of scrub typhus from other undifferentiated fevers, such as leptospirosis or dengue fever, is often very difficult. In addition, an effective vaccine has not yet been developed. As a novel diagnostic and vaccine target for scrub typhus, we described surface cell antigen (sca) family genes encoding autotransporter proteins found in the genome of O. tsutsugamushi. The molecular characteristics and recent findings on the bacterial genes were introduced in this letter.

Cellular and Systemic Interactions of Orientia tsutsugamushi with Mammalian Host

Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi infection and one of main causes of febrile illness in the Asia-Pacific region. It has been estimated that one billion people are at risk and one million new cases arise each year in the endemic region. Despite of aggressive attempts to develop a prophylactic vaccine against scrub typhus during last several decades, all approaches have failed to generate long lasting immunity. In addition, little is known about the immunological pathogenesis of scrub typhus. In this review, we summarized recent findings of cellular and systemic interaction of O. tsutsugamushi with mammalian host, especially focusing on the molecular basis of intracellular invasion and immunological changes observed during the bacterial infection.

The Profiles of Plasma Chemokines Following Unrelated Allogeneic Bone Marrow Transplantation and Their Relationship to Transplant-Related Complications

Chemokines are a family of closely related chemotactic cytokines known to be potent attractors for various leukocyte subsets such as neutrophils, monocytes, or lymphocytes. We investigated the chemokine profiles in 26 patients who received unrelated allogeneic bone marrow transplantation (BMT) and evaluated the relationship of chemokines to transplant-related complications. We measured plasma levels of regulated upon activation normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein-1alpha (MIP-1alpha), macrophage inflammatory protein-1beta (MIP-1beta), and interleukin-8 (IL-8) at BMT day -7, day 0, and day 21. When compared with preBMT levels, the mean level of RANTES was significantly decreased at day 21, and the mean level of IL-8 was significantly elevated at day 21. Methotrexate given for graft-versus-host disease (GVHD) prophylaxis and postBMT infectious complication respectively may have contributed to these plasma chemokine level changes. The mean level of IL-8 was significantly higher in patients with infectious complications at day 21 (p=0.009). However, plasma chemokine levels were not associated with the development of acute GVHD and veno-occlusive disease (VOD). Since chemokine production acts in a local manner, plasma levels may not reflect the actual activity of chemokines in target tissue. Further experimental and clinical studies, including chemokine expression in target tissue, are warranted to define the roles of chemokines following allogeneic BMT.

Correlation between Urinary Oxalate Levels and Enteric Oxalobacter formigenes in Patients with Calcium Oxalate Urolithiasis / 대한비뇨기과학회지

PURPOSE: We performed a prospective study to evaluate the intestinal colonization by Oxalobacter formigenes, and its relationship to the levels of urinary oxalate in patients with calcium oxalate stone disease. MATERIALS AND METHODS: One hundred and three patients with calcium oxalate urolithiasis, with a mean age of 47 years, ranging in age from 21 to 73, followed-up between August 2000 and September 2001, were enrolled in this study. Fresh stool and 24-hour urine samples were performed. The genus specific oligonucleotide sequences, corresponding to homologous regions residing in the oxc gene, which encodes for oxalyl-coenzyme A decarboxylase, were designed. In order to quantify the presence of O. formigenes in clinical specimens, a quantitative-PCR-based assay system, utilizing a competitive DNA template as an internal standard, was developed. Measurements of the urine volume, pH, creatinine clearance, oxalate, calcium, magnesium, phosphate, citrate and uric acid were performed. RESULTS: The intestinal Oxalobacterium was detected by PCR in 45.6% of the patients with calcium oxalate stones. In the patients with stones, who tested negative for the Oxalobacterium, the average urinary oxalate level was 0.36mmol/day, compared to 0.29mmol/day for those patients testing positive (p<0.05). The mean colony forming unit per gram of stool in all the patients was 1.1x107 (0 to 4.1x108). The 24 h urine oxalate level was significantly decreased with the increasing level of O. formigenes colony forming units (r= 0.517, p<0.001). CONCLUSIONS: Our results support the concept that O. formigenes is important in maintaining oxalate homeostasis, and its absence from the gut increases the risk of calcium oxalate urolithiasis, via increases in the level of urinary oxalate.

Isolation and Purification of the Oxalate-Degrading Bacterium Oxalobacter formigenes in Human Feces / 대한비뇨기과학회지

PURPOSE: The absence of the oxalate-degrading bacteria, Oxalobacter formigenes, in the gastrointestinal tract correlates with the formation of calcium-oxalate urolithiasis. The aim of this study was to isolate Oxalobacter from human feces. MATERIALS AND METHODS: The OxB strain, isolated from sheep rumen, was incubated in selective growth media(medium B) in an anaerobic chamber, and its microbiological properties evaluated. Feces from volunteers, who were presumed to have O. formigenes from a polymerase chain reaction-based detection system, was incubated in medium B. The colonies isolated, primarily 7 days after incubation, were successively subcultured, and colony-PCR performed to isolate colonies from the successive subcultures. RESULTS: The colonies of OxB were Gram-negative, non-motile, non-spore forming, rod-shaped cells. The cells were often in pairs or chains. OxB DNA gave rise to an amplicon of the correct molecular size(416 bp) of O. formigenes. The morphology of the colonies from human feces, of which DNA was confirmed to have the same size amplicon of O. formigenes by PCR, was identical to the OxB, both grossly and by Gram stain. Although the morphology of the colonies isolated from the successive subcultures was no different from that of OxB, the PCR positivity of the isolated colonies decreased on successive subculturing, with no PCR-positive colonies from the fifth subculture. CONCLUSIONS: Our results suggest that the microbiological isolation and purification of Oxalobacter formigenes from human feces is a difficult procedure. Special culture conditions will be required to culture Oxalobacter species to reveal the link between O. formigenes and calcium oxalate urolithiasis in humans.

Seroprevalence to Coxiella burnetii in Patients with Acute Febrile Episodes during 1993

Coxiella burnetii is the etiological agent of Q fever, that may occur either acutely or the chronically. To understand the seroepidemiological patterns of C. burnetii infection in Korea, we examined a total of 3,178 sera from patients with acute febrile episodes by using indirect immunofluorescence assay (IFA) for detectable antibodies to C. burnetii and other eight rickettsial antigens. The IFA seropositivity>or=1:20 for C. burnetii phase II was 11.5% (368 out of 3,178 sera). The co-existence of antibodies to other rickettsial antigens was found in 216 out of the 368 positive sera. Thirty-seven point five percent (n=138) had antibodies to R. tsutsugamushi (cutoff>or=1:20), 16% (n=59) to Ehrlichia sennetsu, 14.9% (n=55) to Rickettsia typhi, 13.5% (n=50) to R. akari, 11.4% (n=42) to R. japonica, 8.9% (n=33) to R. prowazekii, 7.6% (n=28) to R. sibirica, and 6.7% (n=25) to R. conorii by IFA, respectively. These results are consistent with previous reports documenting diverse serum cross-reactivity in chronic Q fever. Therefore we excluded the samples that reacted to other rickettsial antigens at same or higher titers than to C. burnetii, resulting in the seropositive rate of 4.1%. The serological prevalence was 2% (n=64) when the conventional cut-off titer of 1:80 was used. Our results suggest that infections with C. burnetii are more prevalent than expected previously and should be differentially diagnosised for febrile illness occurring after exposure to ticks or other vectors.

Serological Analysis of Ehrlichiosis in Korean from 1990 to 1992

Ehrlichia sennetsu is the causative agent of human Sennetsu ehrlichiosis. Ehrlichiosis is an acute and occasionally chronic infectious disease caused by obligate intracellular bacteria in the family Rickettsiaceae. To understand the seroepidemiological patterns of ehrlichiosis in Korea, a total of 2,625 patients with acute febrile episode reported from 1990 to 1992 were surveyed using an indirect fluorescent antibody assay (IFA). The result was as follows. Seropositivity for ehrlichiosis was 3.23% by excluding highly cross-reacted sera with other rickettsial antigens. Sera reacted to E. sennetsu showed the cross reaction with other rickettsia as in the order of R. typhi 49.6%, R. conorii 31.6%, R. japonica 28.1%, C. burnetii 26.4%, R. sibirica 25.8%, O. tsutsugamushi 25.8%, R. akari 25.4%, and R. prowazekii 25.4%. Sexual difference in the seropositivity was not noted. The age groups of fifties and under the tenth showed higher prevalence than others. Seropositivity was most prevalent in July and August. As for regional distribution, Chonbuk (10.5%) showed the highest seropositive rate. Geographical distribution of the seropositivity covered most area except Cheju province in Korea.

Serological Analysis of Epidemic Typhus in Korea from 1990 to 1992

No abstract available.

Gene Cloning of the Epstein-Barr Virus (EBV) Antigen Reactive with the Serum from EBV-infected Patients / 감염

BACKGROUND: Epstein-Barr virus (EBV) is causative agent of infectious mononucleosis and nasopharyngeal carcinoma and associated with Burkitt lymphoma and other tumors. The recombinant protein is needed for the rapid and sensitive serodiagnosis of EBV infection. METHODS: EBV gene encoding the protein reactive with the sera of EBV-infected patient was cloned and characterized with lambda gt11 expression library of cDNA of EBV B95-8 strain. RESULTS: The recombinant proteins from clone 12, 15 and 21 were expressed as 120, 118, 160 kDa-usion protein with beta-galactosidase, respectively, which were reactive with IgG anti-EBV antibody-positive sera, but not with anti-EBV antibody-negative sera. A homology search of the DNA sequence of the cloned gene with EBV B95-8 sequences revealed that those were located at 61716~62087, 61898~62085, and 102128~103158, respectively. These positions correspond to BFRF3, BFRF3, and BZLF1, respectively, which were reported as immunogenic protein which evoked strong and longstanding antibody response and had no sequence homology with the proteins of other herpesviruses. All the patients' sera were reactive with clone 12 protein, but only 5 out of 9 patients' sera were reactive with clone 21 protein. CONCLUSION: Clone 21 protein expressing BFRF3 fragment was immunoreactive in patient sera from natural EBV infection and was regarded as useful candidate for the serodiagnosis of EBV infection.

Increased expression of adhesion molecules on human umbilical vein endothelial cells by Orientia tsutsugamushi infection

Scrub typhus is caused by Orientia tsutsugamushi characterized by fever, headache, lymphadenopathy and eschar formation. Infiltration of inflammatory cells around blood vessels and within the affected organs is known to be pathologic hallmark of the scrub typhus. Recently, expression of adhesion molecules on vascular endothelial cells was implicated as an important pathogenic mechanism in rickettsial disease. This study was performed to examine the expression of adhesion molecules and to investigate its role in the pathogenesis of O. tsutsugamushi infection. The expression of adhesion molecules on human umbilical vein endothelial cells (HUVEC) was measured by flow cytometry and indirect immunofluorescence. Expression of E-selectin, ICAM-1 and VCAM-1 was significantly increased 4 hours after the infection and persisted at least for 24 hours. Expression of those molecules was not induced by killed O. tsutsugamushi. Adhesion of polymorphonuclear cells and mononuclear cells to HUVEC was increased after the infection with O. tsutsugamushi. In conclusion, adhesion molecules are expressed on HUVEC during the infection of live O. tsutsugamushi and those molecules can contribute to the infiltration of inflammatory cells during the infection.

47kDa Protein of Orientia tsutsugamushi Do a Critical Role in Invasion to Eucaryotic Cells by Binding to Cell Surface Heparan Sulfate

No Abstract Available.

Infectivity of Orientia tsutsugamushi to Various Eukaryotic Cells and Their Cellular Invasion Mechanism

Orientia tsutsugamushi is obligate intracellular bacterium that grows within the cytoplasm of the eukaryotic host cells. Therefore capability of the attachment, entry into the host cell and intracellular survival should be critical process for oriential infection. In this study we investigated the cellular invasion mechanism of Orientia tsutsugamushi and the role of transmembrane heparan sulfate proteoglycan, which binds diverse components at the cellular microenvironment and is implicated as host cell receptors for a variety of microbial pathogens. First of all Orientia tsutsugamushi can invade a wide range of nonprofessional phagocytic cells including fibroblast, epithelial cells a#nd endothelial cells of various host species, including B and T lymphocytes. Thus, it was postulated that the attachment of O. tsutsugamushi requires the recognition of ubiquitous surface structures of many kinds of host cells. Treatments with heparan sulfate and heparin inhibited the infection of Orientia tsutsugamushi in dose-dependent manner for L cell, mouse fibroblast, whereas other glycosaminoglycans such as chondroitin sulfate had no effect. Collectively, these findings provide strong evidence that initial interaction with heparan sulfate proteoglycan is required for the oriential invasion into host cells.

Identification of Mycobacterium avium complex ( MAC ) clinical Strains to a Species Level by Sequencing and PCR - SSCP Analysis of rpoB DNA

A recent study showed that comparative sequence analysis of rpoB DNAs could reveal natural relationships in genus Mycobacterium [J Clin Microbiol. 37 (6). 1999]. rpoB DNAs showed interspecies variation and intraspecies conservation, Based on these data, we developed polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) protocols which enable species differentiation in genus Mycabacterium. When this assay was applied to 24 clinical isolates identified as M. avium complex (MAC) by biochemical test, these were successfully differentiated into M. avium and M. intracellulare. These results were concordant with those obtained by 16s rDNA analysis. It is the first report that PCR-SSCP analysis of rpoB DNA could be used for species differentiation of MAC strains.

Antigenicity of the G2 Glycoprotein in Cell - Mediated Immune Response Against Hantanvirus Infection

Hemorrhagic fever with renal syndrom is an acute febrile disease which is caused by Hantanvirus and several other viruses that belong to the genus Hantavirus. Gl and G2 glycoproteins of Hantanvirus have been thought to be involved in protective immunity against Hantanvirus infection. In this study, the antigenicity of G1 and G2 glycoproteins in cell mediated immune response was investigated. When peripheral blood mononuclear cell fraction from recovered hemorrhagic fever with renal syndrome patient was cultivated with a recombinant protein containing amino-terminal 78 amino acids of G2 glycoprotein, these cells were activated to proliferate and secreted significant amount of interleukin-2 and interferon-r. These results suggest that T cell epitope exists in the amino-terminal region of G2 glycoprotein.

Molecular Cloning of the Major Immunogen of Orientia tsutsugamushi Thai Strains and Development Passive Hemagglutination Test

The 56-kilodalton protein genes of Orientia tsutsugamushi TA678, TA686, TA716, TA763 strains were amplified by PCR. The amplified products were sequenced and cloned into pIH821 vector. The recombinant proteins were expressed in Escherichia coli as fusion proteins with maltose binding protein. The recombinant proteins were purified and used for the sensitization of sheep RBCs and the reactivity of the recombinant 56-kDa proteins of Orientia tsutsugamushi TA 678, TA686, TA716 strains were analyzed with 40 sera from scrub typhus patients in Korea, 40 sera from scrub typhus in Thailand, Malaysia and Philippines. The 56-kDa protein coding DNA sequence of Orientia tsutsugamushi TA678, TA686, TA716 show 70 to 88% homology with other known strains and four variable regions are also observed. 39 of 40 sera from scrub typhus patients in Korea showed the strongest reactivity to the recombinant protein of Boryong strain and one sera showed the strongest reactivity to the recombinant protein of Gilliam strain. 14 of 40 sera from patients in Thailand, Malaysia and Philippines showed the strongest reactivity to the recombinant protein of TA686 strain and 12 sera showed the strongest reactivity to the recombinant protein of TA716 strain. No serum from patients in Thailand, Malaysia and Philippines showed the strongest reactivity to the recombinant protein of Boryong strain.

The role of CDI on the antigen recognition of human CD3+CD4-CD8 T lymphocyte clone specific to M.tyberculosis

No abstract available.

Production and characterization of human T-cell clones reactive to mycobacterium tuberculosis

No abstract available.

Production and characterization of human T cell hybridomas

No abstract available.

Seroepidemiological survey of scrub typhus in Korea, 1991

No abstract available.