We have developed experimental murine Campylobacter infection models which demonstrate efficient establishment and reproducible, high-level colonization. Following oral inoculation, wild-type C3H mice with normal enteric flora were colonized inconsistently and inefficiently by C. jejuni strain 81-176. However, C3H mice with a limited gut flora (LF) were efficiently colonized at high levels (10 8 CFU/g of stool or large intestine tissue) followed by clearance after several weeks. Large intestine tissue showed minimal to mild inflammation at days 7 and 28 postinoculation. In striking contrast, C3H SCID mice with the same limited flora remained persistently colonized at a consistently high level until they were euthanized 8 months postinoculation. Lower gastrointestinal tract tissue from LF-SCID mice showed marked to severe inflammation in the colon and cecum at days 7 and 28 and intense inflammation of the stomach at day 28. These findings indicate that although the innate response alone cannot block colonization persistence, it is sufficient to orchestrate marked gut inflammation. Moreover, the adaptive immune response is critical to mediate C. jejuni clearance from the colonized gut. To validate our LF murine model, we verified that motility and chemotaxis are critical for colonization. Insertion-deletion mutations were generated in motB and fliI, which encode products essential for motility and flagellar assembly, and in the presumptive chemotaxis gene cheA (histidine kinase). All mutants failed to establish colonization in LF mice. Our limited flora murine colonization models serve as tractable, reproducible tools to define host responses to C. jejuni infection and to identify and characterize virulence determinants required for colonization.
Summary
A Campylobacter jejuni two-component signal transduction system (TCSTS), designated dccR-dccSMicroarray analysis identified several genes encoding putative periplasmic and membrane proteins as being regulated by this two-component system; binding of purified His-tagged DccR to the promoter region of two of these genes supports a direct protein-DNA interaction. A conserved repeat sequence was identified in the promoter regions of these genes and in three other promoter regions in the genome, including that of an operon encoding a putative type I secretion system. Two of the regulated target genes were found to be essential for optimal colonization. Both the two-component system and the putative regulated genes have uncharacterized homologues in other Campylobacter and Helicobacter spp., suggesting that they may perform an important function in colonization among a variety of related pathogenic species.
Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease (ILD) affecting the pulmonary interstitium. Other forms of interstitial lung disease exist, and in some cases, an environmental etiology can be delineated. The diagnosis of IPF is typically established by high-resolution CT scan. IPF tends to have a worse prognosis than other forms of ILD. Familial cases of IPF also exist, suggesting a genetic predisposition; telomerase mutations have been observed to occur in familial IPF, which may also explain the increase in IPF with advancing age. Alveolar epithelial cells are believed to be the primary target of environmental agents that have been putatively associated with IPF. These agents may include toxins, viruses, or the autoantibodies found in collagen vascular diseases. The mechanism of disease is still unclear in IPF, but aberrations in fibroblast differentiation, activation, and proliferation may play a role. Epithelial-mesenchymal transition may also be an important factor in the pathogenesis, as it may lead to accumulation of fibroblasts in the lung and a disruption of normal tissue structure. Abnormalities in other components of the immune system, including T cells, B cells, and dendritic cells, as well as the development of ectopic lymphoid tissue, have also been observed to occur in IPF and may play a role in the stimulation of fibrosis that is a hallmark of the disease. It is becoming increasingly clear that the pathogenesis of IPF is indeed a complex and convoluted process that involves numerous cell types and humoral factors.
We recently reported the development of a multianalyte serum algorithm to identify nodal status in non-small cell lung cancer (NSCLC) patients facing an anatomic resection with curative intent. This study aims to enhance the overall performance characteristics of this test by adding autoantibody biomarkers identified through immunoproteomic discovery. More specifically, we used sera from 20 NSCLC patients to probe 2-D immunoblots of HCC827 lysates for tumor-associated autoantigens. Relevant differences in immunoreactivity associated with pathological nodal status were then identified via tandem mass spectrometry. Identified autoantigens were then developed into Luminex immunobead assays alongside a series of autoantigen targets relevant to early-disease detection. These assays were then used to measure circulating autoantibody levels in the identical cohort of NSCLC patients used in our original study. This strategy identified 11 autoantigens found primarily in patients with disease progression to the locoregional lymph nodes. Custom Luminex-based ''direct-capture'' assays (25 total; including autoantibody targets relevant to early-disease detection) were assembled to measure autoantibody levels in sera from 107 NSCLC patients. Multivariate classification algorithms were then used to identify the optimal combination of biomarkers when considered collectively with our original 6-analyte serum panel. The new algorithm resulting from this analysis consists of TNF-a, TNF-RI, MIP-1a and autoantibodies against Ubiquilin-1, hydroxysteroid-(17-b)-dehydrogenase, and triosephosphate isomerase. The inclusion of autoantibody biomarkers provided a dramatic improvement in the overall test performance characteristics, relative to the original test panel, including an 11% improvement in the classification efficiency.Lung cancer is by far the leading cause of cancer-related mortality worldwide, with non-small cell lung cancer (NSCLC) accounting for roughly 85% of the cases reported annually. 1,2 Approximately 25-30% of NSCLC patients present with localized disease and are eligible for a complete anatomic resection as a potential means for a cure. 3-5 However, as many as 40% of patients with no apparent metastatic progression (i.e., N 0 disease) will die from recurrent disease within 5 years of tumor resection; 6 suggesting that systemic tumor cell dissemination (locoregional or distant) had already occurred at the time of surgery, but went undetected by current clinical and pathological staging methods.In this direction, we recently reported the establishment of a 6-analyte serum algorithm to identify a patient's true (pathologic) nodal status using a cohort of preoperative NSCLC patients (n ¼ 107) and Luminex-based immunobead assays for 47 distinct biomarkers implicated in disease status and/or progression. 7 Using the ''Random Forest'' multivariate classification algorithm developed by Breiman and Cutler, we identified the most efficacious combination of the individually statistically-relevant biomarkers for classifying patien...
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