Search

COVID‐19 induces re‐circulating long‐lived memory B cells (MBC) that, upon re‐encounter with the pathogen, are induced to mount immunoglobulin responses. During convalescence, antibodies are subjected to affinity maturation, which enhances the antibody binding strength and generates new specificities that neutralize virus variants. Here, we performed a single‐cell RNA sequencing analysis of spike‐specific B cells from a SARS‐CoV‐2 convalescent subject. After COVID‐19 vaccination, matured infection‐induced MBC underwent recall and differentiated into plasmablasts. Furthermore, the transcriptomic profiles of newly activated B cells transiently shifted toward the ones of atypical and CXCR3+ B cells and several B‐cell clonotypes massively expanded. We expressed monoclonal antibodies (mAbs) from all B‐cell clones from the largest clonotype that used the VH3‐53 gene segment. The in vitro analysis revealed that some somatic hypermutations enhanced the neutralization breadth of mAbs in a putatively stochastic manner. Thus, somatic hypermutation of B‐cell clonotypes generates an anticipatory memory that can neutralize new virus variants. [ABSTRACT FROM AUTHOR]

Submerged freshwater macrophytes are crucial for the functioning of lakes. Their growth and survival follow environmental conditions like light, temperature, and nutrient availability. Hence, the impending increase in water temperature as well as changes of nutrients and turbidity will lead to changes in macrophyte geographic and depth distribution: Herein, we assess these potential changes. We apply an eco‐physiological macrophyte growth model to simulate biomass growth and survival of virtual species defined by random trait combinations within expert‐derived trait ranges for oligotraphentic, mesotraphentic, and eutraphentic species groups in deep lakes in Bavaria, Germany, which cover clear, moderate, and turbid lake conditions. The emergent potential species richness is compared with empirically observed species richness to evaluate general predictions for current conditions. Thereafter, we apply the model to scenarios of temperature increase and of turbidity and nutrient change to assess potential changes in species richness and the influence of species' traits on being an environmental change 'winner' or 'loser'. We find a cross‐lake, hump‐shaped pattern of potential species richness along depth. This largely reflects observed patterns, although mismatches were also detected and might be explained by missing processes and environmental heterogeneity within the lake. Rising temperature leads to increased richness of potential species in all lake types, species groups, and depths. Turbidity and nutrient change effects depend on depth and lake type. 'Loser species' under increased turbidity and nutrient level are light consumptive and sensible to disturbances, while 'winner species' have a high biomass production. These findings show that the hump‐shaped depth distributions of submerged macrophyte diversity can emerge solely considering eco‐physiology. The differential responses to environmental changes imply that management measures must account for lake type because those responses can have opposite trends depending on lake depth and type. [ABSTRACT FROM AUTHOR]

With increasing risks from natural hazards in alpine regions in Austria OEBB‐Infra and Hoffmann‐Consult have developed a consistent methodology for condition assessment, prediction, and life cycle optimization of protective structures. Based on a thorough assessment of the asset stock standardized life cycles for key structures like rockfall and avalanche protection structures have been derived. The developed life cycle models allow a generalized assessment of asset condition, residual service life, and remaining asset value. In contrast to typical transport assets, protective structures are both subject to natural aging processes and random events with a certain occurrence rate. Beyond standardized life cycles on network level an adjustment to project level is necessary to account for actual condition development and asset specific events. The paper provides an overview on the developed generic life cycle with application to rockfall protection structures with prices 2022 in Austria. [ABSTRACT FROM AUTHOR]

Objective: We have recently shown that priming of synovial fibroblasts (SFs) drives arthritis flares. Pathogenic priming of SFs is essentially mediated by epigenetic reprogramming. Bromodomain and extraterminal motif (BET) proteins translate epigenetic changes into transcription. Here, we used a BET inhibitor (I‐BET151) to target inflammatory tissue priming and to reduce flare severity in a murine experimental arthritis model. Methods: BALB/c mice were treated by intraperitoneal injection or by local injection in the paw with I‐BET151, which blocks the interaction of BET proteins with acetylated histones. We assessed the effects of I‐BET151 on acute arthritis and/or inflammatory tissue priming in a model of repeated injections of monosodium urate crystals or zymosan into the mouse paw. I‐BET151 was given before arthritis induction, at peak inflammation, or after healing of the first arthritis bout. We performed transcriptomic (RNA‐Seq), epigenomic (ATAC‐Seq), and functional (invasion, cytokine production, migration, senescence, metabolic flux) analyses of murine and human SFs treated with I‐BET151 in vitro or in vivo. Results: Systemic I‐BET151 administration did not affect acute inflammation but abolished inflammatory tissue priming and diminished flare severity in both preventive and therapeutic treatment settings. I‐BET151 was also effective when applied locally in the joint. BET inhibition also inhibited osteoclast differentiation, while macrophage activation in the joint was not affected. Flare reduction after BET inhibition was mediated, at least in part, by rolling back the primed transcriptional, metabolic, and pathogenic phenotype of SFs. Conclusion: Inflammatory tissue priming is dependent on transcriptional regulation by BET proteins, making them promising therapeutic targets for prevention of arthritis flares in previously affected joints. [ABSTRACT FROM AUTHOR]

Host cell proteases such as TMPRSS2 are critical determinants of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) tropism and pathogenesis. Here, we show that antithrombin (AT), an endogenous serine protease inhibitor regulating coagulation, is a broad‐spectrum inhibitor of coronavirus infection. Molecular docking and enzyme activity assays demonstrate that AT binds and inhibits TMPRSS2, a serine protease that primes the Spike proteins of coronaviruses for subsequent fusion. Consequently, AT blocks entry driven by the Spikes of SARS‐CoV, MERS‐CoV, hCoV‐229E, SARS‐CoV‐2 and its variants of concern including Omicron, and suppresses lung cell infection with genuine SARS‐CoV‐2. Thus, AT is an endogenous inhibitor of SARS‐CoV‐2 that may be involved in COVID‐19 pathogenesis. We further demonstrate that activation of AT by anticoagulants, such as heparin or fondaparinux, increases the anti‐TMPRSS2 and anti‐SARS‐CoV‐2 activity of AT, suggesting that repurposing of native and activated AT for COVID‐19 treatment should be explored. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease 2019 (COVID‐19) as global pandemic disease has been adversely affecting public health and social life with considerable loss of human life worldwide. Therefore, there is an urgent need for developing novel therapeutics to combat COVID‐19. The causative agent of COVID‐19 is SARS‐CoV‐2 which targets human angiotensin converting enzyme 2 (ACE2) as cellular receptor via its spike (S) protein. In this context, interfering with the binding of SARS‐CoV‐2 S protein to target molecules could provide a promising strategy to find novel therapeutic agents against SARS‐CoV‐2. The purpose of the current study was to identify potential peptidomimetics against S protein with a combination of structure‐based virtual screening methods and in vitro assays. Methods: The candidates were inspected in terms of ADME properties, drug‐likeness, as well as toxicity profiles. Additionally, molecular docking and dynamics simulations were performed to predict binding of the studied ligands to spike protein. Results: Biological evaluation of the compounds revealed that PM2 molecule exhibits some antiviral activity. Conclusion: In summary, this study highlights the importance of combining in silico and in vitro techniques in order to identify antiviral compound to tackle COVID‐19 and presents a new scaffold that may be structurally optimized for improved antiviral activity. [ABSTRACT FROM AUTHOR]

Effective vaccines and monoclonal antibodies have been developed against coronavirus disease 2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). However, the appearance of virus variants with higher transmissibility and pathogenicity is a major concern because of their potential to escape vaccines and clinically approved SARS‐CoV‐2‐ antibodies. Here, we use flow cytometry‐based binding and pseudotyped SARS‐CoV‐2 neutralization assays to determine the efficacy of boost immunization and therapeutic antibodies to neutralize the dominant Omicron variant. We provide compelling evidence that the third vaccination with BNT162b2 increases the amount of neutralizing serum antibodies against Delta and Omicron variants, albeit to a lower degree when compared to the parental Wuhan strain. Therefore, a third vaccination is warranted to increase titers of protective serum antibodies, especially in the case of the Omicron variant. We also found that most clinically approved and otherwise potent therapeutic antibodies against the Delta variant failed to recognize and neutralize the Omicron variant. In contrast, some antibodies under preclinical development potentially neutralized the Omicron variant. Our studies also support using a flow cytometry‐based antibody binding assay to rapidly monitor therapeutic candidates and serum titers against emerging SARS‐CoV‐2 variants. [ABSTRACT FROM AUTHOR]

Neutralizing antibodies against SARS‐CoV‐2 are important to protect against infection and/or disease. Using an assay to detect antibodies directed against the receptor binding domain (RBD) of SARS‐CoV‐2 Spike, we identified individuals with SARS‐CoV‐2 infection after an outbreak at a local health institution. All but one COVID‐19 patient developed detectable anti‐RBD antibodies and 77% had virus neutralizing antibody titers of >1:25. Antibody levels declined slightly over time. However, we still detected virus neutralizing antibody titers in 64% of the COVID‐19 patients at >300 days after infection, demonstrating durability of neutralizing antibody levels after infection. Importantly, full COVID‐19 vaccination of these individuals resulted in higher antibody titers compared to fully vaccinated individuals in the absence of prior infection. These data demonstrate long‐lived antibody‐mediated immunity after SARS‐CoV‐2 infection, and a clear benefit of two vaccine doses for recovered individuals. [ABSTRACT FROM AUTHOR]

TRIANNI mice carry an entire set of human immunoglobulin V region gene segments and are a powerful tool to rapidly isolate human monoclonal antibodies. After immunizing these mice with DNA encoding the spike protein of SARS‐CoV‐2 and boosting with spike protein, we identified 29 hybridoma antibodies that reacted with the SARS‐CoV‐2 spike protein. Nine antibodies neutralize SARS‐CoV‐2 infection at IC50 values in the subnanomolar range. ELISA‐binding studies and DNA sequence analyses revealed one cluster of three clonally related neutralizing antibodies that target the receptor‐binding domain and compete with the cellular receptor hACE2. A second cluster of six clonally related neutralizing antibodies bind to the N‐terminal domain of the spike protein without competing with the binding of hACE2 or cluster 1 antibodies. SARS‐CoV‐2 mutants selected for resistance to an antibody from one cluster are still neutralized by an antibody from the other cluster. Antibodies from both clusters markedly reduced viral spread in mice transgenic for human ACE2 and protected the animals from SARS‐CoV‐2‐induced weight loss. The two clusters of potent noncompeting SARS‐CoV‐2 neutralizing antibodies provide potential candidates for therapy and prophylaxis of COVID‐19. The study further supports transgenic animals with a human immunoglobulin gene repertoire as a powerful platform in pandemic preparedness initiatives. [ABSTRACT FROM AUTHOR]

To monitor infection by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and successful vaccination against coronavirus disease 2019 (COVID‐19), the kinetics of neutralizing or blocking anti‐SARS‐CoV‐2 antibody titers need to be assessed. Here, we report the development of a quick and inexpensive surrogate SARS‐CoV‐2 blocking assay (SUBA) using immobilized recombinant human angiotensin‐converting enzyme 2 (hACE2) and human cells expressing the native form of surface SARS‐CoV‐2 spike protein. Spike protein‐expressing cells bound to hACE2 in the absence or presence of blocking antibodies were quantified by measuring the optical density of cell‐associated crystal violet in a spectrophotometer. The advantages are that SUBA is a fast and inexpensive assay, which does not require biosafety level 2‐ or 3‐approved laboratories. Most importantly, SUBA detects blocking antibodies against the native trimeric cell‐bound SARS‐CoV‐2 spike protein and can be rapidly adjusted to quickly pre‐screen already approved therapeutic antibodies or sera from vaccinated individuals for their ACE2 blocking activities against any emerging SARS‐CoV‐2 variants. [ABSTRACT FROM AUTHOR]

Investigating diversity gradients helps to understand biodiversity drivers and threats. However, one diversity gradient is rarely assessed, namely how plant species distribute along the depth gradient of lakes. Here, we provide the first comprehensive characterization of depth diversity gradient (DDG) of alpha, beta, and gamma species richness of submerged macrophytes across multiple lakes. We characterize the DDG for additive richness components (alpha, beta, gamma), assess environmental drivers, and address temporal change over recent years. We take advantage of yet the largest dataset of macrophyte occurrence along lake depth (274 depth transects across 28 deep lakes) as well as of physiochemical measurements (12 deep lakes from 2006 to 2017 across Bavaria), provided publicly online by the Bavarian State Office for the Environment. We found a high variability in DDG shapes across the study lakes. The DDGs for alpha and gamma richness are predominantly hump‐shaped, while beta richness shows a decreasing DDG. Generalized additive mixed‐effect models indicate that the depth of the maximum richness (Dmax) is influenced by light quality, light quantity, and layering depth, whereas the respective maximum alpha richness within the depth gradient (Rmax) is significantly influenced by lake area only. Most observed DDGs seem generally stable over recent years. However, for single lakes we found significant linear trends for Rmax and Dmax going into different directions. The observed hump‐shaped DDGs agree with three competing hypotheses: the mid‐domain effect, the mean–disturbance hypothesis, and the mean–productivity hypothesis. The DDG amplitude seems driven by lake area (thus following known species–area relationships), whereas skewness depends on physiochemical factors, mainly water transparency and layering depth. Our results provide insights for conservation strategies and for mechanistic frameworks to disentangle competing explanatory hypotheses for the DDG. [ABSTRACT FROM AUTHOR]

WHICH ANTIVIRAL TREATMENT OPTIONS ARE SUITABLE FOR THERAPY OF PATIENTS INFECTED WITH THE OMIC... Treatment with recombinant monoclonal antibodies (mAbs) that neutralize SARS-CoV-2 can reduce the risk for severe disease. In contrast, neutralization of the Omicron variant is dramatically reduced,1 indicating that immunity following infection by previously circulating SARS-CoV-2 variants provides little to no protection against the Omicron variant. Keywords: antibody; omicron; SARS-CoV-2; spike EN antibody omicron SARS-CoV-2 spike 1 3 3 05/31/22 20220501 NES 220501 The severe acute respiratory syndrome coronavirus 2 Omicron variant (B.1.1.529) swept the globe with breathtaking speed, rapidly displacing the Delta variant and causing record numbers of new infections. [Extracted from the article]

Copyright of Bautechnik is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Goal of this study was to investigate, whether sialendoscopy in obstructive salivary gland disorders affects patients' oral health‐related quality of life compared to healthy individuals, and to determine factors that might influence this relationship. Study design Retrospective observational study. Setting: University of Kiel, Department of Otorhinolaryngology, Head and Neck Surgery. Subjects and methods: A group of 130 patients, undergoing sialendoscopy between 01/2004 and 06/2017 was considered. Oral health‐related quality of life was assessed using the OHIP‐G14 (Oral Health Impact Profile) in combination with a custom‐made questionnaire on satisfaction and success in relation to sialendoscopy. Results: Oral health‐related quality of life of patients without dentures or with removable dentures was significantly worse than in the healthy population, whereas the necessity of multiple additional follow‐up treatments was associated with worse oral health‐related quality of life. No essential predisposing factors were identified. Average satisfaction with the intervention was observed to be x̅ = 4.33 (SD = 3.69) on a visual analogue scale from 1 (=very satisfied) to 10 (=very unsatisfied). A longer follow‐up period and a higher patients' age were positively related, whereas removal of salivary gland during follow‐up was negatively related to satisfaction. In 113 cases (86.9%) long‐term preservation was accomplished and 115 (88.5%) patients would repeat a sialendoscopy in case needed. Conclusion: In summary, sialendoscopy resulted in long‐term high subjective and objective success rates. However, oral health‐related quality of life scores did not reach those levels found in the healthy population. [ABSTRACT FROM AUTHOR]

Billions of cells die every day in higher organisms as part of the normal process of tissue homeostasis. During special conditions like in development, acute infections, mechanical injuries, and immunity, cell death is a common denominator and it exerts profound effects in the outcome of these scenarios. To prevent the accumulation of aged, superfluous, infected, damaged and dead cells, professional phagocytes act in a rapid and efficient manner to clear the battle field and avoid spread of the destruction. Neutrophils are the most abundant effector immune cells that extravasate into tissues and can turn injured tissues into gory battle fields. In peace times, neutrophils tend to patrol tissues without provoking inflammatory reactions. We discuss in this review actual and forgotten knowledge about the meaning of cell death during homeostatic processes and drive the attention to the importance of the action of neutrophils during patrolling and for the maintenance or recovery of the homeostatic state once the organism gets attacked or injured, respectively. In this fashion, we disclose several disease conditions that arise as collateral damage of physiological responses to death. [ABSTRACT FROM AUTHOR]

Objective In vitro studies suggest that the type I interferon (IFN) signature seen in most lupus patients results from Fcγ receptor-mediated uptake of nucleic acid-containing immune complexes by plasmacytoid dendritic cells and engagement of endosomal Toll-like receptors. The aim of this study was to reexamine the pathogenesis of the IFN signature in vivo. Methods Lupus was induced in mice by injecting pristane. Some mice were treated with normal immunoglobulin or with cobra venom factor to deplete complement. The IFN signature was evaluated by polymerase chain reaction. The IFN signature also was determined in C4-deficient patients and control subjects. Results Wild-type C57BL/6 mice with pristane-induced lupus developed a strong IFN signature, which was absent in immunoglobulin-deficient (μMT), C3−/−, and CD18−/− mice. Intravenous infusion of normal IgM, but not IgG, restored the IFN signature in μMT mice, and the IFN signature in wild-type mice was inhibited by depleting complement, suggesting that opsonization by IgM and complement is involved in IFN production. Consistent with that possibility, the levels of 'natural' IgM antibodies reactive with dead cells were increased in pristane-treated wild-type mice compared with untreated controls, and in vivo phagocytosis of dead cells was impaired in C3-deficient mice. To examine the clinical relevance of these findings, we identified 10 C4-deficient patients with lupus-like disease and compared them with 152 C4-intact patients and 21 healthy controls. In comparison with C4-intact patients, C4-deficient patients had a different clinical/serologic phenotype and lacked the IFN signature. Conclusion These studies define previously unrecognized roles of natural IgM, complement, and complement receptors in generating the IFN signature in lupus. [ABSTRACT FROM AUTHOR]

A new member of the lysyl oxidase (LOX) family, lysyl oxidase-like 4 (LOXL4), is overexpressed in head and neck squamous cell carcinoma (HNSCC) compared to normal squamous epithelium. A monoclonal antibody (mAb) derived from fusion of Balb/c mouse splenocytes immunized with LOXL4 specific peptide was used to evaluate its therapeutic efficacy in 15 HNSCC cell lines associated with LOXL4 overexpression. For xenograft experiments 41 severe combined immunodeficient (SCID) mice were used to analyze LOXL4-mAb mediated tumor regression. Cell viability was analyzed using cytotoxicity-, and clonogenic-assays. Significant suppression of tumor cell growth was observed in 12 out of 15 (80%) tumor cell lines after 48 hr exposure to the mAb (LD50 of 15 µg/ml to 45 µg/ml). The effect induced by the antibody could be blocked by pre-incubation of the antibody with the peptide used for immunization of the mice and antibody generation, indicating that the effect of the antibody is specific. In mice inoculated with HNSCC cells, i.v. injections of the LOXL4-mAb resulted within 70 days in extensive tumor destruction in all treated animals whereas no tumor regression occurred in control animals. In mice pre-immunized i.v. with LOXL4-mAb and subsequently injected with HNSCC cells, tumor development was considerably delayed in contrast to non LOXL4-mAb pre-immunized animals. These results demonstrate that the LOXL4-mAb has potent antitumor activity and suggest its suitability as a therapeutic immune agent applicable to HNSCC exhibiting tumor specific upregulation of LOXL4. [ABSTRACT FROM AUTHOR]

Objective. The nuclear protein heterogeneous nuclear RNP A2/B1 (hnRNP A2/B1) is involved in posttranscriptional regulation of gene expression. It is constitutively expressed in lymphoid organs and highly upregulated in the synovial tissue of patients with rheumatoid arthritis (RA), who may also generate autoantibodies to this protein. This study was undertaken to investigate the potential involvement of hnRNP A2/B1 in the pathogenesis of autoimmune arthritis, by silencing hnRNP A2/B1 expression in 2 animal models of RA. Methods. Collagen-induced arthritis (CIA) and the K/BxN serum-transfer model were used as animal models of RA. Efficient silencing of hnRNP A2/B1 was achieved using a liposome-based carrier system for delivery of small interfering RNAs. Expression of hnRNP A2/B1 was analyzed by flow cytometry, reverse transcription- quantitative polymerase chain reaction, Western blotting, and immunohistochemistry. The number of osteoclasts was determined by tartrate-resistant acid phosphatase staining. Cytokine levels and anticollagen antibody levels were measured by enzyme-linked immunosorbent assay. Results. Efficient silencing of hnRNP A2/B1 was achieved in all lymphoid organs. In both experimental models, the incidence and severity of arthritis were largely reduced and bone erosion was not detectable as compared to the control groups. Down-modulation of hnRNP A2/B1 significantly interfered with the production of proinflammatory cytokines from monocyte/macrophages, but not from T cells. Consistent with these findings, production of T cell cytokines was not impaired when cells were restimulated in vitro with type II collagen. Furthermore, levels of anticollagen antibodies were not affected by hnRNP A2/B1 silencing. Conclusion. Our findings suggest that hnRNP A2/B1 has an important role in regulation of the innate immune system, especially at the level of monocyte/macrophage activation. Therefore, down-modulation of hnRNP A2/B1 seems to affect primarily the effector phase of autoimmune arthritis. [ABSTRACT FROM AUTHOR]

Recently, we showed that increased SLPI levels prevent human papillomavirus (HPV) infections and metastasis in smoking-induced, non-HPV-driven head and neck squamous cell carcinoma (HNSCC). Here, we focus on the role of SLPI in non-HPV-driven HNSCC, investigating tumor tissue and non-neoplastic mucosa from the same patients and from non-HNSCC patients. Gene and protein expression of SLPI and gene expression of annexin 2 (a SLPI receptor), nicotine receptor ( α7AChR) and arylhydrocarbon receptor ( AhR) were analyzed in HNSCC patients (20 smokers; 16 nonsmokers). SLPI-results were correlated with the patients' HPV status. Non-neoplastic mucosa of HNSCC patients and normal mucosa from non-HNSCC individuals (18 smokers; 20 nonsmokers) was analyzed for the same parameters. Tissue of the inferior turbinate ( n = 10) was incubated with nicotine for analysis of the same genes. SLPI gene expression in tumor tissue was 109.26 ± 23.08 times higher in smokers versus nonsmokers. Non-neoplastic mucosa of smokers showed also higher SLPI gene expression (10.49 ± 1.89-fold non-HNSCC; 18.02 ± 3.93-fold HNSCC patients). Annexin 2 gene expression was also increased in smokers. SLPI data were corroborated by immunohistochemistry. A nicotine dependent correlation between SLPI and annexin 2 gene expression ( r2 = 0.15, p < 0.001) was shown ex vivo. Nicotine and smoking increased α7AChR and AhR gene expression. Five patients, showing no/low SLPI expression, were HPV16-positive. A significant correlation between smoking and SLPI expression in tumors and to our knowledge for the first time in mucosa of HNSCC and non-HNSCC patients was established. Together with the finding that all patients with HPV infection showed no/low SLPI expression, these data support our intriguing hypothesis that smoking induced upregulated SLPI prevents HPV infections. [ABSTRACT FROM AUTHOR]

The ferritic steel 16Mo3 is commonly used for heat exchangers and steam generators. The temperature loading conditions for these applications range typically from 200 to 500°C. For a basic characterization of the steel 16Mo3, the properties were determined by means of tensile tests with different strain rates. At 200 and 300°C, a negative strain-rate sensitivity was observed which is due to dynamic strain ageing (Portevin-LeChâtelier effect). To characterize the low cycle fatigue (LCF) behavior of this steel, isothermal strain-controlled LCF tests were carried out at 200 and 500°C at different strain amplitudes. The cyclic stress response curves are showing principally different courses at the investigated temperatures. The stress relaxation behavior was obtained by cyclic load enhancement tests at various strain amplitudes with dwell times of 30 and 120 s. [ABSTRACT FROM AUTHOR]

The causal role of human papillomaviruses (HPV) in squamous cell carcinogenesis of tonsillar cancers (TSCC) depends on the activity of the viral oncoproteins E6 and E7, leading to inactivation of the cellular tumor suppressor p53 and the retinoblastoma gene product pRb. Because of the negative feedback mechanisms, the pRb inactivation causes an increase of the inhibitor of the cyclin-dependent kinases p16 [ABSTRACT FROM AUTHOR]

The heterogeneous nuclear ribonucleoprotein A2 (hnRNP-A2) has been described as an important autoantigen in rheumatoid arthritis (RA) since it is targeted by autoantibodies, autoreactive T cells, and is aberrantly expressed in synovial cells in patients. To identify hnRNP-A2-specific T-cell epitopes possibly associated with pathogenicity, we used an innovative approach. We first scanned 280 overlapping hnRNP-A2 peptides for binding to the RA-associated class II molecules HLA-DR4 and HLA-DR1, leading to a comprehensive selection of binders. The selected peptides were tested in IFN-γ-specific ELISPOT assay: PBMC from 18% of RA patients showed a significant IFN-γ response to hnRNP-A2 peptides, 15% to the overlapping sequences 117-133 and/or 120-133, whereas PBMC from healthy individuals tested negative. We measured proliferative responses to these two peptides in another cohort of patients with RA or osteoarthritis: positive responses were found in 28% of RA, but also in 11% of osteoarthritis patients and these responses could be blocked by anti-MHC class II Ab. Remarkably, the presence of 117/120-133-specific T cells was significantly associated with active disease in RA patients, and bone erosion appeared to be more common in T-cell positive patients. These data suggest involvement of hnRNP-A2 specific cellular autoimmune responses in RA pathogenesis. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a severe autoimmune disorder of unknown etiology. Major autoantigens include immunoglobulin G (which is targeted by rheumatoid factor), citrullinated proteins, and the heterogeneous nuclear ribonucleoprotein (hnRNP) A2. To obtain more insight into the pathogenic role of arthritogenic autoantigens, we studied autoimmune responses in two animal models of RA, which are independent of immunization with exogenous antigens, namely human tumor necrosis factor-α (TNF-α)-transgenic (hTNFtg) mice and rats with pristane-induced arthritis (PIA). Serologic and cellular studies revealed autoantibodies to hnRNP-A2 in these animals and pronounced T-cell reactivity to hnRNP-A2 and the presence of rheumatoid factor in PIA, while citrullinated antigens were not targeted. Furthermore, hnRNP-A2 was found to be highly overexpressed in the joints of mice and rats affected by arthritis. Thus, unspecific proinflammatory stimuli, such as TNF-α or pristane, may induce pathogenic autoimmune reactions that may drive an inflammatory process, leading to the development of erosive arthritis. [ABSTRACT FROM AUTHOR]

Background. Matrix metalloproteinases (MMPs) play an important role in tumor invasiveness. This study investigates the expression status of MMPs and tissue inhibitors of metalloproteinases (TIMPs) in head and neck squamous cell carcinomas (HNSCC). Methods. Of 48 laryngeal squamous cell carcinoma (LSCC) biopsies and 10 HNSCC cell lines, mRNA was isolated, reversely transcribed, and subjected to polymerase chain reaction (PCR) amplifying MMP-1, MMP-2, MMP-9, MMP-10, TIMP-1, and TIMP-2. Silver nitrate–stained gel electrophoresis demonstrated MMP and TIMP expression status. Exemplary immunohistochemistry and zymography confirmed translation and enzyme activity. Results. Densitometric analysis revealed MMP-2 expression and lymph node metastases to be positively and TIMP-1 and TIMP-2 to be negatively correlated with lymph node metastases. TIMP-2 expression and tumor size were negatively correlated. MMP-1, MMP-9, and MMP-10 expression were not correlated to metastasis formation or tumor size. Conclusions. Our results suggest that MMP-2 expression enhances, whereas TIMP-1 and TIMP-2 both suppress, cancer spread in LSCC. © 2005 Wiley Periodicals, Inc. Head Neck27: XXX–XXX, 2005 [ABSTRACT FROM AUTHOR]