| 1. |
- Ajona, Daniel, et al.
(författare)
-
Complement C4d-specific antibodies for the diagnosis of lung cancer
- 2018
-
Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 9:5, s. 6346-6355
-
Tidskriftsartikel (refereegranskat)abstract
- Development of molecular markers that help to identify high-risk individuals or diagnose indeterminate pulmonary nodules could have a major impact on lung cancer clinical management. In this study, we evaluated the diagnostic potential of a newly-developed ELISA that specifically detects complement C4d. We measured this marker in five independent cohorts of plasma and bronchoalveolar lavage samples from lung cancer patients and controls. In case-control studies, the area under the ROC curve for the diagnosis of lung cancer was 0.82 (95%CI = 0.72-0.92) in plasma samples, and 0.80 (95%CI = 0.69 to 0.90) in bronchoalveolar lavage fluids. In a set of plasma samples from the MILD CT-screening trial, the assay was unable to discriminate between asymptomatic high-risk individuals with or without early stage lung cancer. On the contrary, in two independent cohorts of individuals with indeterminate pulmonary nodules, plasma samples from patients with lung cancer nodules presented higher levels of C4d than those from patients with benign nodules. Using a target population of patients with 8 to 30 mm nodules, the test identified likely benign lung nodules with 84% negative predictive value and 54% positive predictive value, at 89% specificity and 44% sensitivity. In conclusion, the specific determination of C4d may serve as an adjunct to current clinical practice in the diagnosis of indeterminate pulmonary nodules.
|
|
| 2. |
- Bartoszek, Krzysztof, et al.
(författare)
-
Are official confirmed cases and fatalities counts good enough to study the COVID-19 pandemic dynamics? A critical assessment through the case of Italy
- 2020
-
Ingår i: Nonlinear dynamics. - : SPRINGER. - 0924-090X .- 1573-269X. ; 101, s. 1951-1979
-
Tidskriftsartikel (refereegranskat)abstract
- As the COVID-19 outbreak is developing the two most frequently reported statistics seem to be the raw confirmed case and case fatalities counts. Focusing on Italy, one of the hardest hit countries, we look at how these two values could be put in perspective to reflect the dynamics of the virus spread. In particular, we find that merely considering the confirmed case counts would be very misleading. The number of daily tests grows, while the daily fraction of confirmed cases to total tests has a change point. It (depending on region) generally increases with strong fluctuations till (around, depending on region) 15-22 March and then decreases linearly after. Combined with the increasing trend of daily performed tests, the raw confirmed case counts are not representative of the situation and are confounded with the sampling effort. This we observe when regressing on time the logged fraction of positive tests and for comparison the logged raw confirmed count. Hence, calibrating model parameters for this viruss dynamics should not be done based only on confirmed case counts (without rescaling by the number of tests), but take also fatalities and hospitalization count under consideration as variables not prone to be distorted by testing efforts. Furthermore, reporting statistics on the national level does not say much about the dynamics of the disease, which are taking place at the regional level. These findings are based on the official data of total death counts up to 15 April 2020 released by ISTAT and up to 10 May 2020 for the number of cases. In this work, we do not fit models but we rather investigate whether this task is possible at all. This work also informs about a new tool to collect and harmonize official statistics coming from different sources in the form of a package for the R statistical environment and presents the "COVID-19 Data Hub."
|
|
| 3. |
- Bartoszek, Krzysztof, et al.
(författare)
-
Controversies around the statistical presentation of data on mRNA-COVID 19 vaccine safety in pregnant women
- 2022
-
Ingår i: Journal of Reproductive Immunology. - : ELSEVIER IRELAND LTD. - 0165-0378 .- 1872-7603. ; 151
-
Tidskriftsartikel (refereegranskat)abstract
- The work entitled "Preliminary Findings of mRNA Covid-19 Vaccine Safety in Pregnant Persons" published on April 21, 2021, in The New England Journal of Medicine, presented data collected from American surveillance systems and registries. However, problems with an unanimous interpretation of those results appeared in the public debate and citing articles. Some stated that the risk of miscarriage in vaccinated women was similar to historical values reported before the vaccines approval. The others stated that risk was highly above-normative in women vaccinated during the first and second trimesters. We found several problems with the statistical treatment/interpretation of the originally presented values: a substantial percentage (up to 95.6%) of missing data, an incorrect denominator used for risk estimation, and too short follow-up that disabled the evaluation of the studys endpoint in numerous participants. Eventually, the Authors published a corrigendum on September 8, 2021, and pointed to updated data. Herein, we explain the statistical controversies raised by the original presentation and stress that analyzing the trade-off between knowledge and confusion brought by the release of incomplete results of such a high social interest, should aid in solving the dilemma of whether to publish preliminary data or none.
|
|
| 4. |
- Blom, Anna, et al.
(författare)
-
A novel method for direct measurement of complement convertases activity in human serum.
- 2014
-
Ingår i: Clinical and Experimental Immunology. - : Oxford University Press (OUP). - 0009-9104 .- 1365-2249. ; 178:1, s. 142-153
-
Tidskriftsartikel (refereegranskat)abstract
- Complement convertases are enzymatic complexes that play a central role in sustaining and amplification of the complement cascade. Impairment of complement function directly or indirectly leads to pathologic conditions including higher infection rate, kidney diseases, autoimmune- or neurodegenerative diseases and ischemia-reperfusion injury. An assay for direct measurement of activity of the convertases in patient sera is not available. Existing assays testing convertase function are based on purified complement components and thus, convertase formation occurs under non-physiological conditions. We designed a new assay, in which C5 blocking compounds enabled separation of the complement cascade into two phases: the first ending at the stage of C5 convertases and the second ending with membrane attack complex formation. Use of rabbit erythrocytes or antibody-sensitized sheep erythrocytes as the platforms for convertase formation enabled easy readout based on measurement of hemolysis. Thus, properties of patient sera could be studied directly regarding convertase activity and membrane attack complex formation. Another advantage of this assay was the possibility to screen for host factors such as C3 nephritic factor and other anti-complement autoantibodies, or gain-of-function mutations, which prolong half-live of complement convertases. Herein, we present proof of concept, detailed description and validation of this novel assay.
|
|
| 5. |
- Blom, Anna, et al.
(författare)
-
Antibodies reactive to cleaved sites in complement proteins enable highly specific measurement of soluble markers of complement activation.
- 2015
-
Ingår i: Molecular Immunology. - : Elsevier BV. - 1872-9142 .- 0161-5890. ; 66:2, s. 164-170
-
Tidskriftsartikel (refereegranskat)abstract
- An emerging number of diseases and therapeutic approaches with defined involvement of the complement system justify a need for specific markers reflecting activation of particular effector arms of the complement cascade. Measurement of such soluble markers in circulation is a challenge since the specificity of antibodies must be limited to activated complement fragments but not predominant and ubiquitous parental molecules. Existing assays for the measurement of soluble, activated complement proteins are based on the detection of conformational neoepitopes. We tested an alternative approach based on detection of short linear neoepitopes exposed at the cleavage sites after activation of the actual complement component. Obtained antibodies reactive to C4d and C5b fragments enabled us to set up highly specific sandwich ELISAs, which ensured trustful measurements without false positive readouts characteristic for some of the widely used assays.
|
|
| 6. |
- Blom, Anna M., et al.
(författare)
-
Testing the Activity of Complement Convertases in Serum/Plasma for Diagnosis of C4NeF-Mediated C3 Glomerulonephritis
- 2016
-
Ingår i: Journal of Clinical Immunology. - : Springer Science and Business Media LLC. - 0271-9142 .- 1573-2592. ; , s. 517-527
-
Tidskriftsartikel (refereegranskat)abstract
- Autoantibodies termed C3-nephritic factor (C3NeF), which stabilize convertases of the alternative complement pathway, often stimulate autoinflammatory diseases. However, knowledge about analogous autoantibodies acting on the classical pathway (C4NeF) is limited to a few reports, which indicate association with kidney dysfunction, systemic lupus erythematous, and infections. C4NeF may appear independently from C3NeF, but the lack of a routine diagnostic method predisposes C4NeF for being an underestimated player in autoinflammatory episodes. We tested the activity of classical convertases directly in serum/plasma to screen samples from 13 patients with C3 glomerulopathies and identified one patient showing significantly prolonged half-life of these enzymes. Observed effect was reproduced by immunoglobulins purified from patient’s plasma and additionally confirmed on classical convertase built from purified components. Isolated immunoglobulins protected classical convertases from both spontaneous and inhibitor-driven decay but not from C4b proteolysis. The patient had a decreased serum level of C3, elevated sC5b-9, and normal concentrations of factor B and C4. Neither C3NeF nor other autoantibodies directed against alternative pathway proteins (factor H, factor B, factor I, C3, and properdin) were found. Genetic analysis showed no mutations in C3, CFB, CFH, CFI, MCP, THBD, and DGKE genes. Renal biopsy revealed a membranoproliferative pattern with intense C3 deposits. Our results underline the importance of C4NeF as an independent pathogenic factor and a need for the implementation of routine examination of classical convertase activity. Proposed method may enable robust inspection of such atypical cases.
|
|
| 7. |
|
|
| 8. |
- Escudero-Esparza, Astrid, et al.
(författare)
-
Complement inhibitor CSMD1 acts as tumor suppressor in human breast cancer
- 2016
-
Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:47, s. 76920-76933
-
Tidskriftsartikel (refereegranskat)abstract
- Human CUB and Sushi multiple domains 1 (CSMD1) is a membrane-bound complement inhibitor suggested to act as a putative tumor suppressor gene, since allelic loss of this region encompassing 8p23 including CSMD1 characterizes various malignancies. Here, we assessed the role of CSMD1 as a tumor suppressor gene in the development of breast cancer in vitro and in vivo. We found that human breast tumor tissues expressed CSMD1 at lower levels compared to that in normal mammary tissues. The decreased expression of CSMD1 was linked to a shorter overall survival of breast cancer patients. We also revealed that expression of CSMD1 in human breast cancer cells BT-20 and MDA-MB-231 significantly inhibited their malignant phenotypes, including migration, adhesion and invasion. Conversely, stable silencing of CSMD1 expression in T47D cells enhanced cancer cell migratory, adherent and clonogenic abilities. Moreover, expression of CSMD1 in the highly invasive MDA-MB-231 cells diminished their signaling potential as well as their stem cell-like properties as assessed by measurement of aldehyde dehydrogenase activity. In a xenograft model, expression of CSMD1 blocked the ability of cancer cells to metastasize to secondary sites in vivo, likely via inhibiting local invasion but not the extravasation into distant tissues. Taken together, these findings demonstrate the role of CSMD1 as a tumor suppressor gene in breast cancer.
|
|
| 9. |
- Felberg, Anna, et al.
(författare)
-
Elevated expression of complement factor I in lung cancer cells associates with shorter survival–Potentially via non-canonical mechanism
- 2024
-
Ingår i: Translational Research. - 1931-5244. ; 269, s. 1-13
-
Tidskriftsartikel (refereegranskat)abstract
- While numerous membrane-bound complement inhibitors protect the body's cells from innate immunity's autoaggression, soluble inhibitors like complement factor I (FI) are rarely produced outside the liver. Previously, we reported the expression of FI in non-small cell lung cancer (NSCLC) cell lines. Now, we assessed the content of FI in cancer biopsies from lung cancer patients and associated the results with clinicopathological characteristics and clinical outcomes. Immunohistochemical staining intensity did not correlate with age, smoking status, tumor size, stage, differentiation grade, and T cell infiltrates, but was associated with progression-free survival (PFS), overall survival (OS) and disease-specific survival (DSS). Multivariate Cox analysis of low vs. high FI content revealed HR 0.55, 95 % CI 0.32-0.95, p=0.031 for PFS, HR 0.51, 95 % CI 0.25-1.02, p=0.055 for OS, and HR 0.32, 95 % CI 0.12-0.84, p=0.021 for DSS. Unfavorable prognosis might stem from the non-canonical role of FI, as the staining pattern did not correlate with C4d - the product of FI-supported degradation of active complement component C4b. To elucidate that, we engineered three human NSCLC cell lines naturally expressing FI with CRISPR/Cas9 technology, and compared the transcriptome of FI-deficient and FI-sufficient clones in each cell line. RNA sequencing revealed differentially expressed genes engaged in intracellular signaling pathways controlling proliferation, apoptosis, and responsiveness to growth factors. Moreover, in vitro colony-formation assays showed that FI-deficient cells formed smaller foci than FI-sufficient NSCLC cells, but their size increased when purified FI protein was added to the medium. We postulate that a non-canonical activity of FI influences cellular physiology and contributes to the poor prognosis of lung cancer patients.
|
|
| 10. |
- Felberg, Anna, et al.
(författare)
-
Monitoring of the Complement System Status in Patients With B-Cell Malignancies Treated With Rituximab
- 2020
-
Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- Rituximab is a pioneering anti-CD20 monoclonal antibody that became the first-line drug used in immunotherapy of B-cell malignancies over the last twenty years. Rituximab activates the complement system in vitro, but there is an ongoing debate on the exact role of this effector mechanism in therapeutic effect. Results of both in vitro and in vivo studies are model-dependent and preclude clear clinical conclusions. Additional confounding factors like complement inhibition by tumor cells, loss of target antigen and complement depletion due to excessively applied immunotherapeutics, intrapersonal variability in the concentration of main complement components and differences in tumor burden all suggest that a personalized approach is the best strategy for optimization of rituximab dosage and therapeutic schedule. Herein we critically review the existing knowledge in support of such concept and present original data on markers of complement activation, complement consumption, and rituximab accumulation in plasma of patients with chronic lymphocytic leukemia (CLL) and non-Hodgkin’s lymphomas (NHL). The increase of markers such as C4d and terminal complement complex (TCC) suggest the strongest complement activation after the first administration of rituximab, but not indicative of clinical outcome in patients receiving rituximab in combination with chemotherapy. Both ELISA and complement-dependent cytotoxicity (CDC) functional assay showed that a substantial number of patients accumulate rituximab to the extent that consecutive infusions do not improve the cytotoxic capacity of their sera. Our data suggest that individual assessment of CDC activity and rituximab concentration in plasma may support clinicians’ decisions on further drug infusions, or instead prescribing a therapy with anti-CD20 antibodies like obinutuzumab that more efficiently activate effector mechanisms other than complement.
|
|
| 11. |
- Felberg, Anna, et al.
(författare)
-
Mutations resulting in the formation of hyperactive complement convertases support cytocidal effect of anti-CD20 immunotherapeutics
- 2019
-
Ingår i: Cancer Immunology, Immunotherapy. - : Springer Science and Business Media LLC. - 0340-7004 .- 1432-0851. ; 68:4, s. 587-598
-
Tidskriftsartikel (refereegranskat)abstract
- Anti-CD20 monoclonal antibodies (mAbs) rituximab and ofatumumab are potent activators of the classical complement pathway, and have been approved for the treatment of B-cell malignancies. However, complement exhaustion and overexpression of complement inhibitors by cancer cells diminish their therapeutic potential. The strategies of targeting membrane complement inhibitors by function-blocking antibodies and the supplementation with fresh frozen plasma have been proposed to overcome tumour cell resistance. We present a novel approach, which utilizes gain-of-function variants of complement factor B (FB), a component of alternative C3/C5 convertases, which augment mAb-activated reactions through a positive feedback mechanism called an amplification loop. If complement concentration is limited, an addition of quadruple gain-of-function FB mutant p.D279G p.F286L p.K323E p.Y363A (or selected single mutants) results in significantly increased complement-mediated lysis of ofatumumab-resistant tumour cells, as well as the complete lysis of moderately sensitive cells. Importantly, this effect cannot be achieved by further increasing ofatumumab concentration. Potentiation of cytotoxic effect towards moderately sensitive cells was less apparent at physiological serum concentration. However, an addition of hyperactive FB could compensate the loss of cytotoxic potential of serum collected from the NHL and CLL patients after infusion of rituximab. Residual levels of rituximab in such sera, in combination with added FB, were able to efficiently lyse tumour cells. We suggest that the administration of gain-of-function variants of FB can restore CDC potential of complement-exhausted serum and maximize the therapeutic effect of circulating anti-CD20 mAbs.
|
|
| 12. |
|
|
| 13. |
- Kamysz, Wojciech, et al.
(författare)
-
In vitro activity of synthetic antimicrobial peptides against Candida
- 2006
-
Ingår i: Polish Journal of Microbiology. - 1733-1331. ; 55:4, s. 303-307
-
Tidskriftsartikel (refereegranskat)abstract
- Yeast-like fungi are the most common cause of fungal infections in humans. Actually, in the age of opportunistic infections and increasing resistance, development of modern antifungal agents becomes a very important challenge. This paper describes synthesis and antimicrobial assay of four naturally occurring peptide antibiotics (aurein 1.2, citropin 1.1, temporin A, uperin 3.6) and three chemically engineered analogues actually passing clinical trials (iseganan, pexiganan, omiganan) against Candida strains isolated from patients with infections of the oral cavity or respiratory tract. The peptides were synthesized using solid-phase method and purified by high-performance liquid chromatography. Biological tests were performed using the broth microdilution method. The antifungal activity of the peptide antibiotics was compared to that of nystatin and amphotericin B. We found synthetic peptides to be generally less potent than amphotericin B or nystatin. However, some of the naturally occurring peptides still retained reasonable antifungal activities which were higher than these of iseganan, pexiganan or omiganan. We think that the naturally occurring peptide antibiotics included in our study can be a good matrix for development of novel antifungal compounds.
|
|
| 14. |
- Kraaij, Tineke, et al.
(författare)
-
Measuring plasma C4D to monitor immune complexes in lupus nephritis
- 2019
-
Ingår i: Lupus Science and Medicine. - : BMJ. - 2053-8790. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Objective Because currently available assays that measure circulating immune complexes (ICx) are suboptimal, a novel assay was recently developed measuring C4d, a stable product of activation of the classical complement pathway. The present study aimed to establish the value of measuring plasma C4d levels in a longitudinal cohort of patients with severe refractory SLE who were treated with a combination therapy of rituximab with belimumab (RTX+BLM). Methods Fifteen patients with SLE who were treated with RTX+BLM in a phase 2A, open label study were included to sequentially measure plasma C4d levels and correlated to well-established markers of ICx-formation, that is, autoantibodies against double-stranded (ds) DNA, autoantibodies against C1q and proteinuria. The performance of plasma C4d measurements, C4 measurements and the ratio of C4d over C4 (C4d:C4) was evaluated. Results After establishing that on RTX+BLM treatment kinetics of C4d levels was distinct from traditional C3 and C4 levels, we found strong correlation of C4d:C4 with anti-dsDNA (R=0.76, p<0.001) and anti-C1q (R=0.65, p<0.001) autoantibody levels, which outperformed both stand-alone C4 and C4d levels. Additionally, changes in C4d:C4 over time correlated strongly with changes in proteinuria (R=0.59, p<0.001) as well as anti-dsDNA (R=0.46, p=0.003) and anti-C1q (R=0.47, p=0.002). Conclusion In patients with severe SLE, plasma C4d levels in relation to C4 levels is useful for longitudinal monitoring after RTX+BLM treatment to reflect amelioration of classical complement activation by ICx as well as proteinuria.
|
|
| 15. |
- Mark, Linda, et al.
(författare)
-
Molecular characterization of the rhesus rhadinovirus (RRV) ORF4 gene and the RRV complement control protein it encodes
- 2007
-
Ingår i: Journal of Virology. - 1098-5514. ; 81:8, s. 4166-4176
-
Tidskriftsartikel (refereegranskat)abstract
- The diversity of viral strategies to modulate complement activation indicates that this component of the immune system has significant antiviral potential. One example is the Kaposi's sarcoma-associated herpesvirus (KSHV) complement control protein (KCP), which inhibits progression of the complement cascade. Rhesus rhadinovirus (RRV), like KSHV, is a member of the subfamily Gammaherpesvirinae and currently provides the only in vivo model of KSHV pathobiology in primates. In the present study, we characterized the KCP homologue encoded by RRV, RRV complement control protein (RCP). Two strains of RRV have been sequenced to date (H26-95 and 17577), and the RCPs they encode differ substantially in structure: RCP from strain H26-95 has four complement control protein (CCP) domains, whereas RCP from strain 17577 has eight CCP domains. Transcriptional analyses of the RCP gene (ORF4, referred to herein as RCP) in infected rhesus macaque fibroblasts mapped the ends of the transcripts of both strains. They revealed that H26-95 encodes a full-length, unspliced RCP transcript, while 17577 RCP generates a full-length unspliced mRNA and two alternatively spliced transcripts. Western blotting confirmed that infected cells express RCP, and immune electron microscopy disclosed this protein on the surface of RRV virions. Functional studies of RCP encoded by both RRV strains revealed their ability to suppress complement activation by the classical (antibody-mediated) pathway. These data provide the foundation for studies into the biological significance of gammaherpesvirus complement regulatory proteins in a tractable, non-human primate model.
|
|
| 16. |
- Martin, Myriam, et al.
(författare)
-
Plasma C4d as marker for lupus nephritis in systemic lupus erythematosus
- 2017
-
Ingår i: Arthritis Research and Therapy. - : Springer Science and Business Media LLC. - 1478-6354 .- 1478-6362. ; 19:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: In the present study, we sought to evaluate the complement activation product C4d as a marker for lupus nephritis in systemic lupus erythematosus (SLE). Methods: C4d levels were determined by enzyme-linked immunosorbent assay in plasma samples of patients with established SLE using a novel approach based on detection of a short linear cleavage neoepitope. Cross-sectional associations were studied in 98 patients with SLE with samples taken at lower or higher respective disease activity. Temporal associations were investigated in 69 patients with SLE who were followed longitudinally for up to 5 years. Plasma samples from 77 healthy donors were included as controls. Results: C4d levels were negligible in healthy control subjects and significantly increased in patients with SLE in the cross-sectional study (p < 0.0001). C4d levels discriminated between higher and lower disease activity according to ROC curve analysis (p < 0.001), exhibiting a positive predictive value of 68%. At higher disease activity, C4d levels correlated with the modified Systemic Lupus Erythematosus Disease Activity Index (p = 0.011) and predominantly with lupus nephritis (p = 0.003), exhibiting a sensitivity of 79% to identify patients with nephritis. High C4d levels together with the presence of anti-dsDNA autoantibodies preceded and thus predicted future lupus nephritis in the longitudinal study (OR 5.4, 95% CI 1.4-21.3). When we considered only patients with renal involvement (19 of 69) during the longitudinal study, we found that high C4d levels alone could forecast recurrence of future lupus nephritis (OR 3.3, 95% CI 1.2-9.6). Conclusions: C4d appears to be a valuable marker for use in monitoring of patients with SLE, particularly for lupus nephritis. Importantly, C4d levels can predict impending flares of lupus nephritis and may thus be useful for informing treatment.
|
|
| 17. |
- Michels, Marloes A.H.M., et al.
(författare)
-
Overactivity of alternative pathway convertases in patients with complement-mediated renal diseases
- 2018
-
Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 9:APR
-
Tidskriftsartikel (refereegranskat)abstract
- Overactivation of the alternative pathway of the complement system is associated with the renal diseases atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G). C3 nephritic factors (C3NeF) play an important role in C3G pathogenesis by stabilizing the key enzymatic complex of complement, the C3 convertase. However, the reliability of assays detecting these autoantibodies is limited. Therefore, in this study, we validated and optimized a prototype hemolytic method for robust detection and characterization of factors causing convertase overactivity in large patient cohorts. The assay assesses convertase activity directly in the physiological milieu of serum and therefore is not restricted to detection of stabilizing autoantibodies such as C3NeF but may also reveal genetic variants resulting in prolonged convertase activity. We first defined clear cutoff values based on convertase activity in healthy controls. Next, we evaluated 27 C3G patient samples and found 16 positive for prolonged convertase activity, indicating the presence of factors influencing convertase stability. In three patients, the overactive convertase profile was persistent over disease course while in another patient the increased stability normalized in remission. In all these four patients, the convertase-stabilizing activity resided in the purified immunoglobulin (Ig) fraction, demonstrating the autoantibody nature. By contrast, the Igs of a familial aHUS patient carrying the complement factor B mutation p.Lys323Glu did not reveal convertase stabilization. However, in serum prolonged convertase activity was observed and segregated with the mutation in both affected and unaffected family members. In conclusion, we present a robust and reliable method for the detection, characterization, and evaluation over time of factors prolonging convertase activity (C3NeF or certain mutations) in patient cohorts. This assay may provide new insights in disease pathogenesis and may contribute to the development of more personalized treatment strategies.
|
|
| 18. |
- Okroj, Marcin, et al.
(författare)
-
A novel mechanism of action of the fumagillin analog, TNP-470, in the B16F10 murine melanoma cell line
- 2005
-
Ingår i: Anti-Cancer Drugs. - 0959-4973. ; 16:8, s. 817-823
-
Tidskriftsartikel (refereegranskat)abstract
- TNP-470, a semisynthetic derivative of fumagillin, is an acknowledged angiogenesis inhibitor, presently undergoing clinical trials. It exerts an anti-proliferative effect directed against endothelial cells. This effect is known to be based on cell cycle inhibition effected by the p53/p21 pathway. We observed short-term toxicity of TNP-470 in the B16F10 murine melanoma cell line in vitro and investigated the mechanism of action. Cell death occurred as soon as 2 h after the addition of TNP-470, without typical apoptotic features. The toxic effect could be modulated and it depended on the type of culture medium or supplementation with anti-oxidants. Addition of N-acetylcysteine protected B16F10 cells from TNP-470-induced death and inhibited an increase in the generation of reactive oxygen species (ROS), which are detected by the 2',7'-dichlorodihydrofluorescein diacetate probe. We conclude that TNP-470 can induce intracellular generation of ROS, which act toxically inside B16F10 cells. One may suggest that this novel activity of TNP-470 might be beneficial in some cases, but it could also be responsible for some undesirable side-effects. The possibility of its modulation gives a prospect for controlling the action of this potential drug and probably its derivatives.
|
|
| 19. |
- Okrój, Marcin, et al.
(författare)
-
Analysis of complement biomarkers in systemic sclerosis indicates a distinct pattern in scleroderma renal crisis
- 2016
-
Ingår i: Arthritis Research and Therapy. - : Springer Science and Business Media LLC. - 1478-6354 .- 1478-6362. ; 18:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The complement system has been implicated in pathogenesis of systemic sclerosis (SSc). The goal of the present study was to evaluate improved complement biomarkers in SSc. Methods: The presence of C4d, reflecting activation of the classical/lectin pathways, C3bBbP corresponding to activation of the alternative pathway, and soluble terminal complement complexes (all complement pathways), was measured in plasma samples by enzyme-linked immunosorbent assay and correlated to clinical parameters. The study included 81 patients with limited cutaneous SSc and 41 with diffuse cutaneous SSc, as well as 47 matched healthy controls and 81 patients with rheumatoid arthritis, 22 with psoriatic arthritis and 20 with ankylosing spondylitis. Skin and kidney biopsies of selected patients were stained to detect deposited C3b as a marker of local complement activation. Results: Biomarkers of activation of all complement pathways were increased in SSc compared with healthy controls and were similar to those in other rheumatic diseases. When patients with SSc were divided into subgroups, a distinct pattern of complement markers was observed in individuals with scleroderma renal crisis (SRC). By functional assay, we confirmed a significant decrease in complement haemolytic activity in SRC vs. non-SRC patients, indicating complement consumption. Further, we detected glomerular deposits of C3b in some patients with SRC. Conclusions: The data indicate that complement activation is an important feature of SRC.
|
|
| 20. |
- Okroj, Marcin, et al.
(författare)
-
Antibodies against Kaposi sarcoma-associated herpes virus (KSHV) complement control protein (KCP) in infected individuals
- 2007
-
Ingår i: Vaccine. - : Elsevier BV. - 1873-2518 .- 0264-410X. ; 25:48, s. 8102-8109
-
Tidskriftsartikel (refereegranskat)abstract
- Kaposi sarcoma-associated herpesvirus (KSHV) is the most important etiopathological factor of Kaposi's sarcoma (KS) and some specific types of malignant lymphomas. One of the viral lytic genes encodes the KSHV complement control protein (KCP), which functionally mimics human complement inhibitors. Although this protein provides an advantage for evading the complement attack, it can serve as target for adaptive immune response. Herein, we identified anti-KCP IgG antibodies in patients with KS and KSHV-related lymphomas. KCP-specific antibodies were only detected in sera of those patients who had high titres of antibodies against lytic or latent KSHV antigens. Complement control protein domain 2 (CCP2) was found to be the most immunogenic part of the KCP protein. Furthermore, pre-incubation of KCP-expressing CHO cells with patient sera containing anti-KCP antibodies resulted in an increased complement deposition when incubated with human serum.
|
|
| 21. |
- Okrój, Marcin, et al.
(författare)
-
C4b-Binding Protein
- 2017
-
Ingår i: The Complement FactsBook : Second Edition - Second Edition. - 9780128104200 ; , s. 251-259
-
Bokkapitel (refereegranskat)abstract
- C4b-binding protein (C4BP) is the main fluid-phase inhibitor of the classical complement pathway. It serves as cofactor in factor I-mediated cleavage of C4b and C3b and it accelerates the decay of complement convertases. The main role of C4BP is to prevent overt complement-mediated inflammation both in solution and on self-molecules recognised by C1q, such as amyloid. Furthermore, C4BP is frequently recruited onto the surface of various pathogens, which allows these to evade immune response. The main isoform of C4BP has a oligomeric structure and consists of seven chains, which confer complement inhibitory activity, and a single chain, which binds anticoagulant protein S and docks the molecule to negatively charged phospholipids exposed, e.g., on the surface of dying cells. Both α- and β- chains are built from complement control protein (CCP) domains typical of complement inhibitors. C4BP is one of the acute-phase proteins and its expression is upregulated by proinflammatory cytokines.
|
|
| 22. |
|
|
| 23. |
- Okroj, Marcin, et al.
(författare)
-
Characterization of the complement inhibitory function of Rhesus rhadinovirus complement control protein (RCP).
- 2009
-
Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 2008:Nov 6., s. 505-514
-
Tidskriftsartikel (refereegranskat)abstract
- Rhesus Rhadinovirus (RRV) is currently the closest known, fully sequenced homolog of human Kaposi's sarcoma-associated herpesvirus (KSHV). Both these viruses encode complement inhibitors: KSHV-complement control protein (KCP) and RRV-complement control protein (RCP). Previously we characterized in detail the functional properties of KCP as complement inhibitor. Herein, we performed comparative analyses for two variants of RCP protein, encoded by RRV strains H26-95 and 17577. Both RCP variants and KCP inhibited human and rhesus complement when tested in hemolytic assays measuring all steps of activation via the classical and the alternative pathway. RCP variants from both RRV strains supported C3b- and C4b-degradation by factor I and decay-acceleration of the classical C3 convertase, similar to KCP. Additionally, the 17577 RCP variant accelerated decay of the alternative C3 convertase, which was not seen for KCP. In contrast to KCP, RCP showed no affinity to heparin and is the first described complement inhibitor in which the binding site for C3b/C4b does not interact with heparin. Molecular modeling shows a structural disruption in the region of RCP that corresponds to the KCP-heparin binding site. This makes RRV a superior model for future in vivo investigations of complement evasion, as RCP does not play a supportive role in viral attachment as KCP does.
|
|
| 24. |
- Okroj, Marcin, et al.
(författare)
-
Effector mechanisms of anti-CD20 monoclonal antibodies in B cell malignancies.
- 2013
-
Ingår i: Cancer Treatment Reviews. - : Elsevier BV. - 1532-1967 .- 0305-7372. ; 39:6, s. 632-639
-
Forskningsöversikt (refereegranskat)abstract
- Activation of the complement system by tumor cells was long believed to only benefit the host. Overexpression of complement inhibitors by many tumor cell types and results obtained in several experimental animal models were all in agreement with this hypothesis. However, recent reports imply that the situation is more complex than initially believed and that under certain circumstances tumor cells may use complement to their own advantage, e.g. by recruitment of suppressor T cells or promoting local angiogenesis. Such a dual role of complement may also be apparent when considering the effect of therapeutic monoclonal antibodies (mAb) used to successfully treat B cell malignancies, such as CD20 mAbs. Some argue that besides direct tumor cell killing by mAbs, two main immune effector mechanisms, complement dependent cytotoxicity (CDC) and antibody dependent cellular cytotoxicity (ADCC), may be competing with each other. Experiments aiming at answering the question whether complement is our friend or foe in mAb therapy ended up with seemingly contradictory conclusions. Herein, we revisit the existing knowledge on this pivotal issue based on rituximab and other anti-CD20 mAb as a model of therapeutic agents.
|
|
| 25. |
- Okrój, Marcin, et al.
(författare)
-
Factor I
- 2017
-
Ingår i: The Complement FactsBook : Second Edition - Second Edition. - 9780128104200 ; , s. 147-154
-
Bokkapitel (refereegranskat)abstract
- Factor I (FI) is a serine protease with narrow specificity restricted to activated complement components C3b and C4b. Supported by appropriate cofactors such as factor H or C4b-binding protein, FI cleaves peptide bonds in C3b/C4b after arginyl residues. By doing so it inhibits further propagation of the complement cascade thus contributing to protection from misguided or excessive complement attack on own cells and tissues. Furthermore, inactivated fragments of C3b bind to specific receptors on immune cells and influence their function such as phagocytosis. Production and secretion of FI into bloodstream is mainly supported by liver but extrahepatic sources were also identified, such as keratinocytes, fibroblasts, monocytes and endothelial cells. Mutations/polymorphism in FI may diminish its secretion or cause loss of function. When leading to complete deficiency, alterations in FI markedly distort the balance between complement activation and inhibition. The outcome is increased rate of bacterial infections and glomerulonephritis. Partial deficiency of FI predisposes to atypical haemolytic uraemic syndrome or age-related macular degeneration.
|
|
