Failure to detect Chlamydia pneumoniae in ear fluids from children with otitis media.
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Child↗
Biomedical subjects
C C Kuo
Publications and source records attributed to C C Kuo.
Further characterization of Chlamydia pneumoniae specific monoclonal antibodies.
Studies using monoclonal antibodies have demonstrated species-specific reactivities with Chlamydia pneumoniae. In this study, further characterization of C. pneumoniae specific monoclonal antibodies TT-205 and RR-402 and description of C. pneumoniae specific antibodies prepared against other isolates are presented. TT-205 and RR-402 were shown to neutralize infectivity. Neutralization in cell culture was specific and enhanced by complement. Attempts to characterize the reactive antigen by immunoblotting, immunoaffinity chromatography and radioimmunoprecipitation were unsuccessful, probably due to difficulties in solubilizing the immunoreactive epitope without denaturing it. Recognition of the determinant by the monoclonal antibodies is labile to physical and chemical treatments suggesting that the reactive epitope is conformational.
Animals↗
Effects of two antibiotic regimens on course and persistence of experimental Chlamydia pneumoniae TWAR pneumonitis.
We studied the effects of two antibiotic regimens on the course of Chlamydia pneumoniae infection in the lungs of Swiss Webster mice. After intranasal challenge with isolates AR-388 (1.3 x 10(7) inclusion-forming units per mouse) and AR-39 (1.5 x 10(6) inclusion-forming units per mouse), groups of animals were treated with either doxycycline (10 mg/kg of body weight once a day for 3 days), azithromycin (10 mg/kg [single dose]), or saline. Responses were assessed by the isolation of organisms in cell culture, detection of TWAR DNA in lung tissues by PCR, and lung histology. Both regimens were effective in clearing infections induced by AR-388 (P = 0.02 and 0.007 for doxycycline and azithromycin, respectively) compared with controls. TWAR DNA was detected in 77 and 25% of culture-negative lungs 2 weeks after treatment of AR-388 and AR-39 infections, respectively. Histological changes showed interstitial pneumonitis and were similar over time for all groups. Single-dose azithromycin produced drug levels in lung tissues above the MICs for the test strains for a period three times longer than that of single-dose doxycycline. We concluded that short-term antibiotic regimens were successful for the treatment of experimental TWAR pneumonitis in mice. TWAR DNA was frequently recovered from lung tissues after apparently successful treatment.
Animals↗
Chlamydia pneumoniae (TWAR).
Chlamydia pneumoniae (TWAR) is a recently recognized third species of the genus Chlamydia that causes acute respiratory disease. It is distinct from the other two chlamydial species that infect humans, C. trachomatis and C. psittaci, in elementary body morphology and shares less than 10% of the DNA homology with those species. The organism has a global distribution, with infection most common among children between the ages of 5 and 14 years. In children, TWAR infection is usually mild or asymptomatic, but it may be more severe in adults. Pneumonia and bronchitis are the most common clinical manifestations of infection, and TWAR is responsible for approximately 10% of cases of pneumonia and 5% of cases of bronchitis in the United States. The microimmunofluorescence serologic assay is specific for TWAR and can distinguish between recent and past infections. The organism can be isolated in cell culture; however, PCR techniques have recently facilitated its detection in tissues and clinical specimens.
Adult↗
In vitro susceptibility of human vascular wall cells to infection with Chlamydia pneumoniae.
Chlamydia pneumoniae is a common respiratory pathogen. Recent studies have demonstrated the presence of C. pneumoniae in coronary and aortic atherosclerotic lesions. To study the role of C. pneumoniae in atherosclerosis, we investigated the susceptibilities of three different cells of the human vascular wall to infection with C. pneumoniae AR-39. These cell types were endothelial cells, smooth muscle cells, and macrophages derived from peripheral blood monocytes. Infection was assessed by using a direct fluorescent antibody to assess inclusion counts. Duplicate cell samples were harvested 3 days postinfection and were passed in HL cells, a susceptible human epithelial cell line, to determine if infectious organisms were produced. Endothelial cells, smooth muscle cells, and macrophages were capable of supporting C. pneumoniae growth in vitro. These results showed that three different cell types known to be important in atherogenesis are susceptible to infection with C. pneumoniae.
Cells, Cultured↗
The 32-kDa glycoprotein of Chlamydia trachomatis is an acidic protein that may be involved in the attachment process.
The 32-kDa glycoprotein of Chlamydia trachomatis was shown to have a pI of 6.2 to 6.4 which distinguished this protein from the chlamydial histone-like protein of similar molecular mass that has a pI of > 10. The initial interaction of the glycan of 32 kDa glycoprotein and HeLa cells was also investigated. Glycan was cleaved from the protein backbone by N-glycanase and radiolabeled with tritium by sodium borohydride reduction. Competition assays showed the binding of glycan to HeLa cells was inhibited by galactose, mannose, and N-acetylglucosamine but not by sedoheptulose and fructose. Untreated and UV-treated organisms inhibited the binding, while heat-inactivated organisms did not. Binding was blocked by rabbit antiserum against whole organisms but not by rabbit anti-155-kDa antiserum or monoclonal antibodies against the lipopolysaccharide and major outer membrane protein.
Bacterial Adhesion↗
Antigen-specific human antibodies from mice comprising four distinct genetic modifications.
Human sequence monoclonal antibodies, which in theory combine high specificity with low immunogenicity, represent a class of potential therapeutic agents. But nearly 20 years after Köhler and Milstein first developed methods for obtaining mouse antibodies, no comparable technology exists for reliably obtaining high-affinity human antibodies directed against selected targets. Thus, rodent antibodies, and in vitro modified derivatives of rodent antibodies, are still being used and tested in the clinic. The rodent system has certain clear advantages; mice are easy to immunize, are not tolerant to most human antigens, and their B cells form stable hybridoma cell lines. To exploit these advantages, we have developed transgenic mice that express human IgM, IgG and Ig kappa in the absence of mouse IgM or Ig kappa. We report here that these mice contain human sequence transgenes that undergo V(D)J joining, heavy-chain class switching, and somatic mutation to generate a repertoire of human sequence immunoglobulins. They are also homozygous for targeted mutations that disrupt V(D)J rearrangement at the endogenous heavy- and kappa light-chain loci. We have immunized the mice with human proteins and isolated hybridomas secreting human IgG kappa antigen-specific antibodies.
Animals↗
Respiratory infection with Chlamydia pneumoniae in middle-aged and older adult outpatients.
This study was undertaken to characterize the epidemiology and clinical presentation of infection with Chlamydia pneumoniae in a population composed primarily of middle-aged and older adults. Pharyngeal swabs and acute and convalescent phase sera were obtained from outpatients presenting with signs and symptoms of an acute respiratory infection. Sera were examined using the micro-immunofluorescence (MIF) test to detect antibody to Chlamydia pneumoniae and complement fixation tests to detect Mycoplasma pneumoniae, influenza A virus, influenza B virus, respiratory syncytial virus and adenovirus. Pharyngeal swab specimens were cultured for Chlamydia pneumoniae and tested for Chlamydia pneumoniae by the polymerase chain reaction (PCR). A total of 743 patients with a mean age of 40.5 +/- 16.1 years were enrolled in the study. Twenty-one patients were serologically positive for acute Chlamydia pneumoniae infection in the MIF test. PCR was positive in 15 of the 20 serologically positive patients tested. Acute Chlamydia pneumoniae infection was identified in 3% (2/76) of subjects with pneumonia, 5% (12/247) of those with bronchitis, 5% (3/61) of those with sinusitis only and 2% (2/103) of those with pharyngitis only. Of the 21 patients with Chlamydia pneumoniae infection, seven (mean age of 33 years) had an antibody pattern suggesting a primary infection while 14 (mean age of 54 years) had a reinfection pattern. Patients with reinfection had milder disease than those with primary infection. PCR testing in the current study confirms the previously proposed serologic criteria of acute Chlamydia pneumoniae infection.
Adolescent↗
Na+ channels must deactivate to recover from inactivation.
We studied the kinetics of recovery from inactivation of voltage-dependent Na+ channels in rat hippocampal CA1 neurons. Recovery proceeded exponentially after an initial delay and was accompanied by a tiny ionic current. Both the delay and the time constant of recovery became shorter with increasing hyperpolarization. Negative to -170 mV, the rate of recovery saturated at approximately 4 ms-1 (22 degrees C). Recovery from block by the anticonvulsant drug diphenylhydantoin was far slower, but the pattern of voltage dependence was very similar. Our results suggest that, analogous to the coupling between Na+ channel activation and the development of inactivation, recovery from inactivation is coupled to channel deactivation. Such coupling ensures very little "leak" Na+ current during recovery and a highly voltage-sensitive repriming of Na+ channels for the next impulse.
Animals↗
Detection of Chlamydia trachomatis in fallopian tube tissue in women with postinfectious tubal infertility.
OBJECTIVE: Biopsy tissues from women with postinfectious tubal infertility were studied for the presence of Chlamydia trachomatis. STUDY DESIGN: Tubal biopsy specimens from 25 women with postinfectious tubal infertility undergoing laparoscopy for repair of fallopian tubes were evaluated by culture, in situ hybridization. Immunocytochemistry, and transmission electron microscopy for the presence of Chlamydia trachomatis. Serum was also tested for Chlamydia trachomatis antibodies. RESULTS: Chlamydia trachomatis was detected in postinfectious tubal biopsy specimens in three of 25 patients by culture, 12 of 24 by in situ hybridization, 15 of 22 by immunoperoxidase stain, and two of 10 by transmission electron microscopy. Serum antibody against Chlamydia trachomatis was detected in 15 of 21 patients. CONCLUSION: Chlamydia trachomatis deoxyribonucleic acid or antigens were detected at a high percentage (19/24 women) in the biopsy tissues of the fimbrial and peritubal adhesions by in situ hybridization or immunoperoxidase stain, suggesting a persistent infection in these women even after antibiotic treatment.
Adult↗
Detection of Chlamydia trachomatis deoxyribonucleic acid in monkey models (Macaca nemestrina) of salpingitis by in situ hybridization: implications for pathogenesis.
OBJECTIVE: Our purpose was to determine whether Chlamydia trachomatis persists in tubal tissues from monkey pocket models of chlamydial salpingitis and tubal infertility and to relate its presence to disease progression and histopathologic mechanisms. STUDY DESIGN: In situ hybridization was used to detect Chlamydia deoxyribonucleic acid in a monkey pocket model of salpingitis and in the direct tubal inoculation monkey model of tubal infertility. Results were correlated with culture and immunocytochemistry results and histopathologic characteristics. RESULTS: Chlamydia deoxyribonucleic acid was detected in the mucosa, submucosa, and deep tissues in the pocket model. In addition, it was present in peritubal adhesions from the direct inoculation model. Deoxyribonucleic acid was found at sites of inflammation and when culture and immunocytochemistry studies were negative. CONCLUSION: The presence of Chlamydia trachomatis deoxyribonucleic acid at sites of inflammation and tissue damage in monkey models of chlamydial salpingitis and tubal infertility suggests that Chlamydia persists and may be directly involved in the stimulation of the immune-mediated tissue destruction associated with Chlamydia trachomatis infections.
Animals↗
Risk of perinatal transmission of Chlamydia trachomatis by mode of delivery.
We compared the transmission rate of Chlamydia trachomatis infection from infected women to their infants after various modes of delivery. After vaginal birth, Chlamydia trachomatis was isolated from 58 of 125 infants with a cephalic presentation, and serological evidence of chlamydial infection was found in another eight. C. trachomatis was isolated from the only infant with a frank breech presentation. After Caesarean birth, C. trachomatis was isolated from two of 10 infants born after rupture of the membranes and from one of six without prior rupture of the membranes. No serological evidence of infection was found in any of the culture-negative infants born by Caesarean section. By survival analysis, rates of transmission were significantly lower after Caesarean section with rupture of the membranes before delivery than after vaginal delivery. Infants born to infected women are at risk of C. trachomatis infection regardless of route of delivery.
Cesarean Section↗
Demonstration of delayed hypersensitivity in Chlamydia trachomatis salpingitis in monkeys: a pathogenic mechanism of tubal damage.
The role of delayed hypersensitivity in the pathogenesis of Chlamydia t trachomatis salpingitis was studied in the monkey "pocket" model. Pigtailed monkeys (Macaca nemestrina) were sensitized by inoculation of live C. trachomatis organisms (E/UW-5/Cx) into subcutaneous pockets containing salpingeal autotransplants. At 21 days, affinity-purified recombinant C. trachomatis heat-shock protein (rhsp60) was injected into pockets either previously sensitized with C. trachomatis or not sensitized in the same monkey. Delayed-type hypersensitivity reaction was observed, characterized by mononuclear cell infiltration with peak reaction at 48 h. Injection of rhsp60 into the pockets of a naive animal did not induce inflammation. This study showed that C. trachomatis infection in monkeys induced delayed hypersensitivity, which is mediated by hsp60. Histologic findings of the salpinx were consistent with delayed hypersensitivity reaction observed in ocular C. trachomatis infection, further suggesting a similar pathogenesis for both salpingitis and trachoma.
Animals↗
Ultrastructural lung pathology of experimental Chlamydia pneumoniae pneumonitis in mice.
The ultrastructural lung pathology of Swiss Webster mice on days 2, 4, 7, 11, 15, and 21 after intranasal inoculation of Chlamydia pneumoniae AR-39 is described. The inflammatory infiltrate was predominantly polymorphonuclear leukocytes on day 2. By day 7, mononuclear cells were most prominent in the infiltrate. On day 2, chlamydial inclusions were found frequently in the bronchial ciliated epithelial cells and less frequently in the interstitial cells that appeared to be macrophages. Free particles of all developmental forms of the chlamydial microorganism were found in the bronchial lumen and alveolar space. These particles were likely organisms released from infected cells. Inclusions as well as free particles were difficult to find after day 4. These ultrastructural observations suggest an immunopathologic basis for the acute phase of the disease process.
Acute Disease↗
Human immunoglobulin transgenes undergo rearrangement, somatic mutation and class switching in mice that lack endogenous IgM.
We have generated transgenic mice that contain human-sequence Ig miniloci and, because they are also homozygous for a targeted disruption of their endogenous heavy chain genes, must rely on the transgene sequences for B cell receptor expression. Although the human transgenes contain only a fraction of the intact human heavy chain locus, these defined sequences are able to at least partially restore the humoral immune system in the mouse. B cells expressing human heavy chains develop in the bone marrow, populate peripheral lymphoid tissue and respond specifically to antigen. Furthermore, the heavy chain transgenes contain both human mu and gamma 1 coding exons as well as the respective mu and gamma 1 switch regions. The sequences included within the transgene are sufficient to direct class switch recombination. Transgene sequences are also sufficient to direct somatic mutation of the class-switched heavy chain genes. These observations define the upper limit of the cis-acting sequences necessary to direct heavy chain class switching and somatic mutation.
Animals↗
Binding of the glycan of the major outer membrane protein of Chlamydia trachomatis to HeLa cells.
Recent studies have shown that the major outer membrane protein (MOMP) of Chlamydia trachomatis is glycosylated. The glycan of the MOMP of C. trachomatis serovar L2 was separated from the glycoprotein with N-glycanase, reduced with tritiated NaBH4, and tested for its ability to interact with HeLa cells. The [3H]glycan was shown to attach readily to HeLa cells at 25 or 37 degrees C. This process was slower at 4 degrees C. Competition for possibly similar receptor sites on HeLa cells between the glycan and a sugar, an aminosaccharide, or elementary bodies (EBs) was then studied. D-Galactose, D-mannose, or N-acetylglucosamine was shown to reduce the attachment of the glycan to HeLa cells at concentrations of 0.1 to 0.5 M. Sedoheptulose, D-fructose, or sialic acid did not inhibit the binding of glycan to HeLa cells. The presence of at least 100 native or UV-inactivated EBs per HeLa cell interfered with the glycan's ability to bind to HeLa cells. Heat-inactivated EBs did not compete with the glycan for binding. In the reverse situation, nonradiolabeled glycan prevented the EBs from infecting and forming inclusions in HeLa cells. Incubation of [3H]glycan with rabbit immune serum prepared against antigens of whole EB and the MOMP inhibited attachment. In contrast, incubation of glycan with mouse monoclonal antibodies against the protein portion of the MOMP or the chlamydial lipopolysaccharide did not inhibit attachment. These results suggest that the glycan portion of the MOMP is involved in the attachment process of C. trachomatis organisms to HeLa cells.
Bacterial Adhesion↗
Isolation and characterization of a gene encoding a Chlamydia pneumoniae 76-kilodalton protein containing a species-specific epitope.
Chlamydia pneumoniae is a human respiratory pathogen. Unlike the other two Chlamydia species, no species-specific antigen has been defined for C. pneumoniae. An immunoreactive clone containing a 0.8-kb fragment was isolated from a C. pneumoniae (AR-39) genomic library by using anti-C. pneumoniae rabbit immune serum. By Southern hybridization analysis of chromosomal digests of the different Chlamydia spp., the 0.8-kb fragment was shown to react specifically with C. pneumoniae. Subcloning of this fragment into the pGEX-1 lambda T expression vector resulted in the expression of a 62-kDa fusion protein. This fusion protein as well as the cleaved C. pneumoniae peptide were recognized by anti-C. pneumoniae rabbit immune serum, while the glutathione S-transferase moiety was not recognized. The fusion protein was used to produce monospecific rabbit antiserum. This antiserum was shown to react with a 76-kDa protein in all C. pneumoniae isolates tested, specifically recognize C. pneumoniae inclusions in tissue culture, and neutralize infectivity of C. pneumoniae in cell culture. No reactivity was observed with Chlamydia trachomatis or Chlamydia psittaci. To isolate the entire coding sequence of the 76-kDa protein, two partially overlapping fragments of C. pneumoniae DNA, a 3.2-kb HindIII fragment and a 1.2-kb PvuII fragment, were isolated, cloned, and sequenced. No significant sequence similarity was found with any previously reported nucleotide or amino acid sequence of the other Chlamydia species. This C. pneumoniae protein containing a species-specific epitope could play a role in pathogenesis and may be useful as a diagnostic tool.
Amino Acid Sequence↗
Diagnosis of fungemia in bone marrow transplantation patients by examination of peripheral blood smears.
Two patients who received BMT for treatment of severe aplastic and AML-M2, developed fungemia during leukopenia. The organisms responsible for the infections were Candida parapsilosis and Rhodotorula glutinis, respectively. Early diagnosis of fungemia in these two patients was made by visualization of fungal blastospores in peripheral blood (PB) smears. These two cases illustrate that cytologic examination of PB smears is a useful method for early detection of fungus infection in BMT patients with leukopenia and unexplained fever in spite of appropriate antibiotic treatment.
Adolescent↗