ResearchPad - monoclonal-antibodies https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[When two are better than one: Modeling the mechanisms of antibody mixtures]]> https://www.researchpad.co/article/elastic_article_14641 With the rise of new antibody combinations in therapeutic regimens, it is important to understand how antibodies work together as well as individually. Here, we investigate the specific case of monoclonal antibodies targeting a cancer-causing receptor or the influenza virus and develop a statistical mechanical framework that predicts the effectiveness of a mixture of antibodies. The power of this model lies in its ability to make a large number of predictions based on a limited amount of data. For example, once 10 antibodies have been individually characterized and their epitopes have been mapped, our model can predict how any of the 210 = 1024 combinations will behave. This predictive power can aid therapeutic efforts by assessing which combinations of antibodies will elicit the most effective response.

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<![CDATA[Conformational Fingerprinting Using Monoclonal Antibodies (on the Example of Angiotensin I-Converting Enzyme-ACE)]]> https://www.researchpad.co/article/N6940fa2d-fa01-4779-89c6-e378a30954bb

During the past 30 years my laboratory has generated 40+ monoclonal antibodies (mAbs) directed to structural and conformational epitopes on human ACE as well as ACE from rats, mice and other species. These mAbs were successfully used for detection and quantification of ACE by ELISA, Western blotting, flow cytometry and immunohistochemistry. In all these applications mainly single mAbs were used. We hypothesized that we can obtain a completely new kind of information about ACE structure and function if we use the whole set of mAbs directed to different epitopes on the ACE molecule. When we finished epitope mapping of all mAbs to ACE (and especially, those recognizing conformational epitopes), we realized that we had obtained a new tool to study ACE. First, we demonstrated that binding of some mAbs is very sensitive to local conformational changes on the ACE surface—due to local denaturation, inactivation, ACE inhibitor or mAbs binding or due to diseases. Second, we were able to detect, localize and characterize several human ACE mutations. And, finally, we established a new concept—conformational fingerprinting of ACE using mAbs that in turn allowed us to obtain evidence for tissue specificity of ACE, which has promising scientific and diagnostic perspectives. The initial goal for the generation of mAbs to ACE 30 years ago was obtaining mAbs to organ-specific endothelial cells, which could be used for organ-specific drug delivery. Our systematic work on characterization of mAbs to numerous epitopes on ACE during these years has lead not only to the generation of the most effective mAbs for specific drug/gene delivery into the lung capillaries, but also to the establishment of the concept of conformational fingerprinting of ACE, which in turn gives a theoretical base for the generation of mAbs, specific for ACE from different organs. We believe that this concept could be applicable for any glycoprotein against which there is a set of mAbs to different epitopes.

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<![CDATA[Monoclonal Antibody Against Stromal Cell-Derived Factor 2]]> https://www.researchpad.co/article/N124d37a7-473d-4a77-85a7-a604c15d4672 ]]> <![CDATA[Field evaluation of a locally produced rapid diagnostic test for early detection of cholera in Bangladesh]]> https://www.researchpad.co/article/5c5ca2d4d5eed0c48441eb87

Background

Cholera remains a substantial health burden in Asia and Africa particularly in resource poor settings. The standard procedures to identify the etiological organism V. cholerae are isolation from microbiological culture from stool as well as Polymerase Chain Reaction (PCR). Both the processes are highly lab oriented, labor extensive, time consuming, and expensive. In an effort to control for outbreaks and epidemics; an effective, convenient, quick and relatively less expensive detection method is imperative, without compromising the sensitivity and specificity that exists at present. The objective of this component of the study was to evaluate the effectiveness of a locally produced rapid diagnostic test (RDT) for cholera diagnosis.

Methods

In Bangladesh, nationwide cholera surveillance is ongoing in 22 hospitals covering all 8 divisions of the country since June, 2016. In the surveillance, stool samples have been collected from patients presenting to hospitals with acute watery diarrhea. Crystal VCTM (Span diagnostics, India) and Cholkit (locally produced RDT) have been used to detect V. cholerae from stool samples. Samples have also been sent to the main laboratory at icddr,b where the culture based isolation is routinely performed. All the tests were carried out for both direct and enriched stool samples. RDT sensitivity and specificity were calculated using stool culture as the gold standard.

Results

A total of 7720 samples were tested. Among these, 5865 samples were solely tested with Crystal VC and 1355 samples with Cholkit whereas 381 samples were tested with both the RDTs. In comparison with culture, direct testing with Crystal VC showed a sensitivity of 72% (95% CI: 50.6% to 87.9%) and specificity of 86.8% (95% CI: 82.8% to 90.1%). After enrichment the sensitivity and specificity was 68% (95% CI: 46.5% to 85.1%) and 97.5% (95% CI: 95.3% to 98.8%) respectively. The direct Cholkit test showed sensitivity of 76% (95% CI: 54.9% to 90.6%) and specificity of 90.2% (95% CI: 86.6% to 93.1%).

Conclusion

This evaluation has demonstrated that the sensitivity and specificity of Cholkit is similar to the commercially available test, Crystal VC when used in field settings for detecting V. cholerae from stool specimens. The findings from this study suggest that the Cholkit could be a possible alternative for cholera endemic regions where V. cholerae O1 is the major causative organism causing cholera.

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<![CDATA[A meta-analysis of anti-interleukin-13 monoclonal antibodies for uncontrolled asthma]]> https://www.researchpad.co/article/5c5ca306d5eed0c48441f014

More and more clinical trials have tried to assess the clinical benefit of anti-interleukin (IL)-13 monoclonal antibodies for uncontrolled asthma. The aim of this study is to evaluate the efficacy and safety of anti-IL-13 monoclonal antibodies for uncontrolled asthma. Major databases were searched for randomized controlled trials comparing the anti-IL-13 treatment and a placebo in uncontrolled asthma. Outcomes, including asthma exacerbation rate, forced expiratory volume in 1 second (FEV1), Asthma Quality of Life Questionnaire (AQLQ) scores, rescue medication use, and adverse events were extracted from included studies for systematic review and meta-analysis. Five studies involving 3476 patients and two anti-IL-13 antibodies (lebrikizumab and tralokinumab) were included in this meta-analysis. Compared to the placebo, anti-IL-13 treatments were associated with significant improvement in asthma exacerbation, FEV1 and AQLQ scores, and reduction in rescue medication use. Adverse events and serious adverse events were similar between two groups. Subgroup analysis showed patients with high periostin level had a lower risk of asthma exacerbation after receiving anti-IL-13 treatment. Our study suggests that anti-IL-13 monoclonal antibodies could improve the management of uncontrolled asthma. Periostin may be a good biomarker to detect the specific subgroup who could get better response to anti-IL-13 treatments. In view of blocking IL-13 alone is possibly not enough to achieve asthma control because of the overlapping pathophysiological roles of IL-13/IL-4 in inflammatory pathways, combined blocking of IL-13 and IL-4 with monoclonal antibodies may be more encouraging.

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<![CDATA[Development of the covalent antibody-DNA conjugates technology for detection of IgE and IgM antibodies by immuno-PCR]]> https://www.researchpad.co/article/5c390bc3d5eed0c48491e355

Immuno-PCR (iPCR) is one of the methods used for the detection of a wide range of analytes and features the high sensitivity of the polymerase chain reaction (PCR) method. iPCR uses antibodies coupled to DNA, followed by the amplification of the attached DNA using RT-PCR. Two major types of antibody-DNA conjugates are currently used, which are obtained as a result of non-covalent (biotin-streptavidin) or covalent interactions. Using a strain-promoted azide-alkyne cycloaddition (SPAAC), we synthesized covalent DNA-antibody conjugates, optimized the reaction conditions, and developed an efficient protocol for the purification of conjugates, with which all unreacted antibodies and oligonucleotides are separated. Covalent DNA-antibody conjugates were tested with iPCR assays that were previously developed for the detection of IgE and IgM antibodies with the use of the supramolecular complex of 5'- and 3'-biotinylated DNA and streptavidin. The results show that the modification of antibodies with amino groups did not allow us to obtain monolabeled antibodies or antibodies with a strictly defined number of DNA-labels. The degree of labeling determined by the dyes introduced through the azido group reflects the actual labeling degree statistically. If the average labeling degree for azido groups is 1.1, the conjugates contain 25% mono-labeled antibodies, 50% double-labeled antibodies, and 25% unlabeled ones. The specificity of the monoclonal antibody to human IgE (BE5) changed after conjugation with the oligonucleotide. The sensitivity of iPCR in the detection of IgM antibodies produced against the LeC disaccharide using a covalent conjugate was similar to that of a supramolecular complex of 5'- and 3'-biotinylated DNA and streptavidin, but the new procedure is two steps shorter.

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<![CDATA[Broadly-Reactive Neutralizing and Non-neutralizing Antibodies Directed against the H7 Influenza Virus Hemagglutinin Reveal Divergent Mechanisms of Protection]]> https://www.researchpad.co/article/5989db08ab0ee8fa60bc9455

In the early spring of 2013, Chinese health authorities reported several cases of H7N9 influenza virus infections in humans. Since then the virus has established itself at the human-animal interface in Eastern China and continues to cause several hundred infections annually. In order to characterize the antibody response to the H7N9 virus we generated several mouse monoclonal antibodies against the hemagglutinin of the A/Shanghai/1/13 (H7N9) virus. Of particular note are two monoclonal antibodies, 1B2 and 1H5, that show broad reactivity to divergent H7 hemagglutinins. Monoclonal antibody 1B2 binds to viruses of the Eurasian and North American H7 lineages and monoclonal antibody 1H5 reacts broadly to virus isolates of the Eurasian lineage. Interestingly, 1B2 shows broad hemagglutination inhibiting and neutralizing activity, while 1H5 fails to inhibit hemagglutination and demonstrates no neutralizing activity in vitro. However, both monoclonal antibodies were highly protective in an in vivo passive transfer challenge model in mice, even at low doses. Experiments using mutant antibodies that lack the ability for Fc/Fc-receptor and Fc/complement interactions suggest that the protection provided by mAb 1H5 is, at least in part, mediated by the Fc-fragment of the mAb. These findings highlight that a protective response to a pathogen may not only be due to neutralizing antibodies, but can also be the result of highly efficacious non-neutralizing antibodies not readily detected by classical in vitro neutralization or hemagglutination inhibition assays. This is of interest because H7 influenza virus vaccines induce only low hemagglutination inhibiting antibody titers while eliciting robust antibody titers as measured by ELISA. Our data suggest that these binding but non-neutralizing antibodies contribute to protection in vivo.

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<![CDATA[Generation of a rabbit single-chain fragment variable (scFv) antibody for specific detection of Bradyrhizobium sp. DOA9 in both free-living and bacteroid forms]]> https://www.researchpad.co/article/5989db5fab0ee8fa60be1253

A simple and reliable method for the detection of specific nitrogen-fixing bacteria in both free-living and bacteroid forms is essential for the development and application of biofertilizer. Traditionally, a polyclonal antibody generated from an immunized rabbit was used for detection. However, the disadvantages of using a polyclonal antibody include limited supply and cross-reactivity to related bacterial strains. This is the first report on the application of phage display technology for the generation of a rabbit recombinant monoclonal antibody for specific detection and monitoring of nitrogen-fixing bacteria in both free-living form and in plant nodules. Bradyrhizobium sp. DOA9, a broad host range soil bacteria, originally isolated from the root nodules of Aeschynomene americana in Thailand was used as a model in this study. A recombinant single-chain fragment variable (scFv) antibody library was constructed from the spleen of a rabbit immunized with DOA9. After three rounds of biopanning, one specific phage-displayed scFv antibody, designated bDOA9rb8, was identified. Specific binding of this antibody was confirmed by phage enzyme-linked immunosorbent assay (phage ELISA). The phage antibody could bind specifically to DOA9 in both free-living cells (pure culture) and bacteroids inside plant nodules. In addition to phage ELISA, specific and robust immunofluorescence staining of both free-living and bacteroid forms could also be observed by confocal-immunofluorescence imaging, without cross-reactivity with other tested bradyrhizobial strains. Moreover, specific binding of free scFv to DOA9 was also demonstrated by ELISA. This recombinant antibody can also be used for the study of the molecular mechanism of plant–microbe interactions in the future.

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<![CDATA[The Presence and Anti-HIV-1 Function of Tenascin C in Breast Milk and Genital Fluids]]> https://www.researchpad.co/article/5989db42ab0ee8fa60bd72cf

Tenascin-C (TNC) is a newly identified innate HIV-1-neutralizing protein present in breast milk, yet its presence and potential HIV-inhibitory function in other mucosal fluids is unknown. In this study, we identified TNC as a component of semen and cervical fluid of HIV-1-infected and uninfected individuals, although it is present at a significantly lower concentration and frequency compared to that of colostrum and mature breast milk, potentially due to genital fluid protease degradation. However, TNC was able to neutralize HIV-1 after exposure to low pH, suggesting that TNC could be active at low pH in the vaginal compartment. As mucosal fluids are complex and contain a number of proteins known to interact with the HIV-1 envelope, we further studied the relationship between the concentration of TNC and neutralizing activity in breast milk. The amount of TNC correlated only weakly with the overall innate HIV-1-neutralizing activity of breast milk of uninfected women and negatively correlated with neutralizing activity in milk of HIV-1 infected women, indicating that the amount of TNC in mucosal fluids is not adequate to impede HIV-1 transmission. Moreover, the presence of polyclonal IgG from milk of HIV-1 infected women, but not other HIV-1 envelope-binding milk proteins or monoclonal antibodies, blocked the neutralizing activity of TNC. Finally, as exogenous administration of TNC would be necessary for it to mediate measurable HIV-1 neutralizing activity in mucosal compartments, we established that recombinantly produced TNC has neutralizing activity against transmitted/founder HIV-1 strains that mimic that of purified TNC. Thus, we conclude that endogenous TNC concentration in mucosal fluids is likely inadequate to block HIV-1 transmission to uninfected individuals.

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<![CDATA[Prognostic Value of NME1 (NM23-H1) in Patients with Digestive System Neoplasms: A Systematic Review and Meta-Analysis]]> https://www.researchpad.co/article/5989dad1ab0ee8fa60bb65d1

Objective

There is a heated debate on whether the prognostic value of NME1 is favorable or unfavorable. Thus, we carried out a meta-analysis to evaluate the relationship between NME1 expression and the prognosis of patients with digestive system neoplasms.

Methods

We searched PubMed, EMBASE and Web of Science for relevant articles. The pooled odd ratios (ORs) and corresponding 95%CI were calculated to evaluate the prognostic value of NME1 expression in patients with digestive system neoplasms, and the association between NME1 expression and clinicopathological factors. We also performed subgroup analyses to find out the source of heterogeneity.

Results

2904 patients were pooled from 28 available studies in total. Neither the incorporative OR combined by 17 studies with overall survival (OR = 0.65, 95%CI:0.41–1.03, P = 0.07) nor the pooled OR with disease-free survival (OR = 0.75, 95%CI:0.17–3.36, P = 0.71) in statistics showed any significance. Although we couldn’t find any significance in TNM stage (OR = 0.78, 95%CI:0.44–1.36, P = 0.38), elevated NME1 expression was related to well tumor differentiation (OR = 0.59, 95%CI:0.47–0.73, P<0.00001), negative N status (OR = 0.54, 95%CI:0.36–0.82, P = 0.003) and Dukes’ stage (OR = 0.43, 95%CI:0.24–0.77, P = 0.004). And in the subgroup analyses, we only find the “years” which might be the source of heterogeneity of overall survival in gastric cancer.

Conclusions

The results showed that statistically significant association was found between NME1 expression and the tumor differentiation, N status and Dukes’ stage of patients with digestive system cancers, while no significance was found in overall survival, disease-free survival and TNM stage. More and further researches should be conducted to reveal the prognostic value of NME1.

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<![CDATA[Development of a Sensitive and Specific Polyclonal Antibody for Serological Detection of Clavibacter michiganensis subsp. sepedonicus]]> https://www.researchpad.co/article/5989daedab0ee8fa60bbfdcd

The quarantine bacterium Clavibacter michiganensis subsp. sepedonicus (Cms) causes bacterial ring rot (BRR) in potato but is difficult to detect, hampering the diagnosis of this disease. ELISA immunoassays have not been widely used to detect Cms because commercially available anti-Cms antibodies detect mainly EPS-producing bacteria and can fail to detect strains that do not produce EPS. In the current study, we developed a new type of polyclonal antibody that specifically detects Clavibacter michiganensis subsp. sepedonicus bacteria irrespective of their EPS level. We first found that the presence of bacterial EPS precluded quantitative measurement of bacteria by currently available immunoenzymatic methods, but that washing Cms cells with acidic and basic buffers to remove EPS before analysis successfully standardized ELISA results. We used a mix of three strains of Cms with diverse EPS levels to generate antigen for production of antibodies recognizing Cms cells with and without an EPS layer (IgG-EPS and IgG-N-EPS, respectively). The resulting IgG-N-EPS recognized almost all Cms strains tested in this work regardless of their mucoidal level. The availability of this new antibody renders immunological diagnostics of Cms more sensitive and reliable, as our newly developed antibodies can be used in many type of immunoassays. This work represents an important step forward in efforts to diagnose and prevent the spread of BRR, and the methods and solutions developed in this work are covered by six Polish, one European and one US patents.

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<![CDATA[Mechanism of Collaborative Enhancement of Binding of Paired Antibodies to Distinct Epitopes of Platelet Endothelial Cell Adhesion Molecule-1]]> https://www.researchpad.co/article/5989d9feab0ee8fa60b73029

Monoclonal antibodies (mAbs) directed to extracellular epitopes of human and mouse Platelet Endothelial Cell Adhesion Molecule-1 (CD31 or PECAM-1) stimulate binding of other mAbs to distinct adjacent PECAM-1 epitopes. This effect, dubbed Collaborative Enhancement of Paired Affinity Ligands, or CEPAL, has been shown to enhance delivery of mAb-targeted drugs and nanoparticles to the vascular endothelium. Here we report new insights into the mechanism underlying this effect, which demonstrates equivalent amplitude in the following models: i) cells expressing a full length PECAM-1 and mutant form of PECAM-1 unable to form homodimers; ii) isolated fractions of cellular membranes; and, iii) immobilized recombinant PECAM-1. These results indicate that CEPAL is mediated not by interference in cellular functions or homophilic PECAM-1 interactions, but rather by conformational changes within the cell adhesion molecule induced by ligand binding. This mechanism, mediated by exposure of partially occult epitopes, is likely to occur in molecules other than PECAM-1 and may represent a generalizable phenomenon with valuable practical applications.

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<![CDATA[NFATc1 phosphorylation by DYRK1A increases its protein stability]]> https://www.researchpad.co/article/5989db50ab0ee8fa60bdbe1e

NFATs are transcription factors involved in immune activation and tumor progression. Previous reports showed that DYRK1A suppressed NFATc2 transcriptional activity through phosphorylation. Nonetheless, our results showed that DYRK1A increased NFATc1/αA protein level and subsequent transcriptional activity. DYRK1A phosphorylation of NFATc1/αA at S261, S278, S403 and S409 interfered with NFATc1 ubiquitination and ubiquitin-proteasome degradation. Our results imply that DYRK1A is a positive kinase in regulation of NFATc1.

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<![CDATA[Pycnosomes: Condensed Endosomal Structures Secreted by Dictyostelium Amoebae]]> https://www.researchpad.co/article/5989db07ab0ee8fa60bc8d0b

Dictyostelium discoideum has been used largely as a model organism to study the organization and function of the endocytic pathway. Here we describe dense structures present in D. discoideum endocytic compartments, which we named pycnosomes. Pycnosomes are constitutively secreted in the extracellular medium, from which they can be recovered by differential centrifugation. We identified the most abundant protein present in secreted pycnosomes, that we designated SctA. SctA defines a new family of proteins with four members in D. discoideum, and homologous proteins in other protists and eumetazoa. We developed a monoclonal antibody specific for SctA and used it to further characterize secreted and intracellular pycnosomes. Within cells, immunofluorescence as well as electron microscopy identified pycnosomes as SctA-enriched dense structures in the lumen of endocytic compartments. Pycnosomes are occasionally seen in continuity with intra-endosomal membranes, particularly in U18666A-treated cells where intraluminal budding is highly enhanced. While the exact nature, origin and cellular function of pycnosomes remain to be established, this study provides a first description of these structures as well as a characterization of reagents that can be used for further studies.

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<![CDATA[Clearance of Human IgG1-Sensitised Red Blood Cells In Vivo in Humans Relates to the In Vitro Properties of Antibodies from Alternative Cell Lines]]> https://www.researchpad.co/article/5989db0eab0ee8fa60bcb4dc

We previously produced a recombinant version of the human anti-RhD antibody Fog-1 in the rat myeloma cell line, YB2/0. When human, autologous RhD-positive red blood cells (RBC) were sensitised with this IgG1 antibody and re-injected, they were cleared much more rapidly from the circulation than had been seen earlier with the original human-mouse heterohybridoma-produced Fog-1. Since the IgG have the same amino acid sequence, this disparity is likely to be due to alternative glycosylation that results from the rat and mouse cell lines. By comparing the in vitro properties of YB2/0-produced Fog-1 IgG1 and the same antibody produced in the mouse myeloma cell line NS0, we now have a unique opportunity to pinpoint the cause of the difference in ability to clear RBC in vivo. Using transfected cell lines that express single human FcγR, we showed that IgG1 made in YB2/0 and NS0 cell lines bound equally well to receptors of the FcγRI and FcγRII classes but that the YB2/0 antibody was superior in FcγRIII binding. When measuring complexed IgG binding, the difference was 45-fold for FcγRIIIa 158F, 20-fold for FcγRIIIa 158V and approximately 40-fold for FcγRIIIb. The dissimilarity was greater at 100-fold in monomeric IgG binding assays with FcγRIIIa. When used to sensitise RBC, the YB2/0 IgG1 generated 100-fold greater human NK cell antibody-dependent cell-mediated cytotoxicity and had a 103-fold advantage over the NS0 antibody in activating NK cells, as detected by CD54 levels. In assays of monocyte activation and macrophage adherence/phagocytosis, where FcγRI plays major roles, RBC sensitised with the two antibodies produced much more similar results. Thus, the alternative glycosylation profiles of the Fog-1 antibodies affect only FcγRIII binding and FcγRIII-mediated functions. Relating this to the in vivo studies confirms the importance of FcγRIII in RBC clearance.

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<![CDATA[Complete mapping of viral escape from neutralizing antibodies]]> https://www.researchpad.co/article/5989db54ab0ee8fa60bdd03c

Identifying viral mutations that confer escape from antibodies is crucial for understanding the interplay between immunity and viral evolution. We describe a high-throughput approach to quantify the selection that monoclonal antibodies exert on all single amino-acid mutations to a viral protein. This approach, mutational antigenic profiling, involves creating all replication-competent protein variants of a virus, selecting with antibody, and using deep sequencing to identify enriched mutations. We use mutational antigenic profiling to comprehensively identify mutations that enable influenza virus to escape four monoclonal antibodies targeting hemagglutinin, and validate key findings with neutralization assays. We find remarkable mutation-level idiosyncrasy in antibody escape: for instance, at a single residue targeted by two antibodies, some mutations escape both antibodies while other mutations escape only one or the other. Because mutational antigenic profiling rapidly maps all mutations selected by an antibody, it is useful for elucidating immune specificities and interpreting the antigenic consequences of viral genetic variation.

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<![CDATA[Development and validation of novel biomarker assays for osteoarthritis]]> https://www.researchpad.co/article/5b419eb0463d7e6c0461640f

Background

Osteoarthritis (OA) is the most common chronic joint disease usually diagnosed at relatively advanced stages when there is irreparable damage to the joint(s). Recently, we have identified two novel biomarkers C3f and V65 which appear to be OA-specific and therefore potential markers of early disease. We report the development of immunoassays for quantitative measure of these two novel biomarkers.

Method

Monoclonal and polyclonal antibodies were generated by immunising mouse and rabbits respectively with peptide-carrier conjugates of C3f and V65. Affinity purified antibodies were used for immunoassays development and assays validated using serum from OA patients and controls.

Results

The ELISAs developed showed spiked recovery of up to 96% for C3f and V65 peptides depending on serum dilutions with a coefficient of variation (CV) <10%. The intra- and inter-assay CVs for C3f and V65 were 1.3–10.8% and 4.2–10.3% respectively. Both assays were insensitive for measurements of the peptides in patients and the use of different signal amplification systems did not increase assay sensitivity.

Conclusion

We have developed two immunoassays for measurements of C3f and V65 peptides biomarkers discovered by our earlier proteomic study. These assays could detect the endogenous peptides in serum samples from patients and controls but lacked sensitivity for accurate measurements of the peptides in patients. Our study highlights the difficulties and challenges of validating biomarker from proteomic studies and demonstrates how to overcome some of the technical challenges associated with developing immunoassays for small peptides.

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<![CDATA[PLoS Neglected Tropical Diseases Issue Image | Vol. 12(8) August 2018]]> https://www.researchpad.co/article/5b9aa08140307c59b21f7956

Immunolocalization of native Cs1 protein (green) in adult C. sinensis

C. sinensis adults were incubated with anti-Cs1 monoclonal antibody. A strong positive reaction was observed in the cells in a granulate, gland-like structure surrounding the acetabulum of C. sinensis adult worms, and a moderately positive reaction was seen in the outer tegument of the acetabulum. Cheng, Xu, et al. (2018)

Image Credit: Xue-Nian Xu, Na Cheng and Yan Zhou

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<![CDATA[Preparation of a novel antiserum to aromatase with high affinity and specificity: Its clinicopathological significance on breast cancer tissue]]> https://www.researchpad.co/article/5989db5aab0ee8fa60bdf697

Aromatase inhibitors have been widely used for the endocrine treatment of estrogen-dependent breast cancer in postmenopausal patients. However, clinicopathological studies of aromatase have been limited due to unsatisfactory specificity and/or restricted availability of anti-aromatase antibodies. Here, we have generated a polyclonal antiserum with high affinity and specificity for human aromatase using a monoclonal antibody tagged immunoaffinity chromatography on an industrial production scale. Our preliminary immunohistochemical analysis of 221 invasive breast cancer cases indicated that 87.3% (193/221) had at least 5% aromatase positive cells. The histoscore for aromatase was inversely correlated with pT (p = 0.019), pN (p = 0.001), stage (p < 0.001), histologic grade (p = 0.003), lymphatic infiltration (p < 0.001), venous infiltration (p < 0.001), and Ki-67 index (p < 0.001). However, cancer aromatase expression was independent of estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 statuses. This antiserum will be applicable to clinicopathological examination of aromatase in addition to ER and PgR for an appropriate use of aromatase inhibitor on the treatment of breast cancer. Further studies on the relationship between Aromatase inhibitors have been widely used for the endocrine treatment of estrogen-dependent breast cancer in postmenopausal patients. However, clinicopathological studies of aromatase have been limited due to unsatisfactory specificity and/or restricted availability of anti-aromatase antibodies. Here, we have generated a polyclonal antiserum with high affinity and specificity for human aromatase using a monoclonal antibody tagged immunoaffinity chromatography on an industrial production scale. Our preliminary immunohistochemical analysis of 221 invasive breast cancer cases indicated that 87.3% (193/221) had at least 5% aromatase positive cells. The histoscore for aromatase was inversely correlated with pT (p = 0.019), pN (p = 0.001), stage (p < 0.001), histologic grade (p = 0.003), lymphatic infiltration (p < 0.001), venous infiltration (p < 0.001), and Ki-67 index (p < 0.001). However, cancer aromatase expression was independent of estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 statuses. This antiserum will be applicable to clinicopathological examination of aromatase in addition to ER and PgR for an appropriate use of aromatase inhibitor on the treatment of breast cancer. Further studies on the relationship between aromatase expression and aromatase inhibitors are warranted.

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<![CDATA[Surface Molecules Released by Trypanosoma cruzi Metacyclic Forms Downregulate Host Cell Invasion]]> https://www.researchpad.co/article/5989da56ab0ee8fa60b8ef20

Background

The question whether metacylic trypomastigote (MT) forms of different T. cruzi strains differentially release surface molecules, and how they affect host cell invasion, remains to be fully clarified. We addressed that question using T. cruzi strains that differ widely in the ability to invade cells.

Methodology/Principal Findings

Metacyclic forms were incubated at 37°C for 1 h in complete D10 medium or in nutrient-deprived PBS containing Ca2+ and Mg2+ (PBS++). The conditioned medium (CM), collected after parasite centrifugation, was used for cell invasion assays and Western blot analysis, using monoclonal antibodies directed to gp82 and gp90, the MT surface molecules that promote and negatively regulate invasion, respectively. CM of poorly invasive G strain (G-CM) contained high amounts of gp90 and gp82, either in vesicles or as soluble molecules. CM of highly invasive CL strain (CL-CM) contained gp90 and gp82 at very low levels. HeLa cells were incubated for 1 h with CL strain MT in D10, in absence or in the presence of G-CM or CL-CM. Parasite invasion was significantly inhibited by G-CM, but not by CL-CM. As G strain MT invasion rate in D10 is very low, assays with this strain were performed in PBS++, which induces invasion-promoting lysosome-spreading. G-CM, but not CL-CM, significantly inhibited G strain internalization, effect that was counteracted by preincubating G-CM with an anti-gp90 monoclonal antibody or anti-gp82 polyclonal antibody that do not recognize live MT. G strain CM generated in PBS++ contained much lower amounts of gp90 and gp82 as compared to CM produced in D10, and exhibited lower inhibitory effect on host cell invasion.

Conclusion/Significance

Our data suggest that the surface molecules spontaneously released by MT impair parasite-host cell interaction, gp82 presumably competing with the molecule expressed on MT surface for the host cell receptor, and gp90 further contributing to down modulate invasion.

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