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Fulltext Anti-hepatitis A seroprevalence among chronic viral hepatitis patients in Kelantan, Malaysia

Ahmad F, Hamzah NA, Mustaffa N, Gan SH

World J Gastroenterol, 2011 Sep 28;17(36):4130-4.
PMID: 22039329 DOI: 10.3748/wjg.v17.i36.4130

To determine the seroprevalence of anti-hepatitis A virus (HAV) antibodies in patients with chronic liver disease (CLD) and to justify the need for hepatitis A vaccination.

Matched MeSH terms: Hepatitis A Antibodies/immunology
Fulltext ABO-Incompatible Living-Donor Kidney Transplantation in a Developing Country: A Multicenter Experience in Malaysia

Gan CC, Jalalonmuhali M, Nordin NZ, Abdul Wahab MZ, Yahya R, Ng KP, et al.

Transplant Proc, 2021 Apr;53(3):856-864.
PMID: 33487455 DOI: 10.1016/j.transproceed.2020.10.038

Malaysia has a low deceased-donor donation rate and has not embarked on a paired kidney exchange program; therefore, ABO-incompatible and HLA-incompatible transplantation remain the main contributor to the sustainability of the national kidney transplantation (KT) program. There were 26 cases of ABO-incompatible KTs performed from 2011 to 2018 in 3 major transplant centers, namely, Hospital Kuala Lumpur, University Malaya Medical Centre, and Prince Court Medical Centre. We collected perioperative and follow-up data through June 2019. The desensitization protocol varies and is center specific: the localized Japanese protocol and Swedish protocol with a target anti-A/B isoagglutinin titer of 16 or 32 on the day of transplant. The induction and tacrolimus-based maintenance protocol was nearly identical. The median follow-up time was 62.3 months (interquartile range, 37.0-79.7). Fifteen subjects had the highest predesensitization anti-A/B titer of ≥32 (57.7%). The acute cellular rejection and antibody-mediated rejection incidence were 12.5% (3 cases) and 8.3% (2 cases), respectively. Patient, graft, and death-censored graft survival rates were 96.2%, 92.3%, and 96.0%, respectively, 1 year post-living-donor KT (LDKT) and 96.2%, 87.2%, and 90.7%, respectively, 5 years post-LDKT. Our experience shows that ABO-incompatible LDKT using a suitable desensitization technique could be a safe and feasible choice for LDKT even with varied desensitization regimens for recipients with relatively high baseline isoagglutinin titers.

Matched MeSH terms: Antibodies/immunology
One-Year Outcomes of Living Related Kidney Transplant in Patients With Preformed HLA Donor-Specific Antibodies: A Single-Center Experience in Malaysia

Jalalonmuhali M, Ng KP, Mohd Shariff NH, Lee YW, Wong AH, Gan CC, et al.

Transplant Proc, 2020 05 21;52(6):1718-1722.
PMID: 32448671 DOI: 10.1016/j.transproceed.2020.02.140

The shortage of deceased donors led to an increase of living related renal transplant performed in the presence of donor-specific antibodies (DSAs) or ABO incompatibilities. There are various desensitization protocols that have been proposed. Here, we describe the outcome of these sensitized patients. This is a prospective cohort study recruiting all kidney transplant recipients from August 2016 until June 2018. Deceased donations, ABO incompatible patients, and sensitized patients who were not prescribed on our desensitization protocol were excluded. Recipients were screened for the presence of HLA-antibodies 1 month before transplant. Those with positive DSA will undergo flow cytometry (risk stratification). We are using a protocol that consisted of intravenous rituximab 200 mg (day -14), intravenous antithymocyte globulin 5mg/kg (day 0-4), plasma exchange post transplant for patients with mean fluorescent intensity (MFI) < 3000, and negative flow cytometry. Those patients with MFI ≥ 3000 or positive flow cytometry need extra cycles pretransplant. A total of 40 patients were recruited, and 20 were sensitized patients. Among the sensitized group 4 of 20 had flow cytometry crossmatch positive, while all had preformed HLA-DSA. A total of 8 of 20 had class I HLA-DSA, 11 of 20 had class II HLA-DSA, and 1of 20 was positive for both class I and II HLA-DSA. Mean immunodominant MFI was 2133.4 (standard deviation [SD], 4451.24) and 1383.7 (SD, 2979.02) for class I and class II, respectively. At 1 year, mean serum creatinine was 108.90 (SD, 25.95) and 118.42 (SD, 31.68) in sensitized and unsensitized patients, respectively. One of 20 unsensitized patients had Banff 1B rejection at 3 months, and there was no significant rejection in sensitized patients at 6 months and 1 year. There was no difference in the occurrence of de novo HLA-DSA between the groups. Desensitization protocols may help to overcome incompatibility barriers in living donor renal transplant. The combination of low-dose rituximab, antithymocyte globulin, and judicious use of plasma exchange has worked well for our cohort.

Matched MeSH terms: Antibodies/immunology
Fulltext Electrochemical Immunosensor for Detection of Aflatoxin B₁ Based on Indirect Competitive ELISA

Azri FA, Sukor R, Selamat J, Abu Bakar F, Yusof NA, Hajian R

Toxins (Basel), 2018 May 11;10(5).
PMID: 29751668 DOI: 10.3390/toxins10050196

Mycotoxins are the secondary toxic metabolites produced naturally by fungi. Analysis of mycotoxins is essential to minimize the consumption of contaminated food and feed. In this present work, an ultrasensitive electrochemical immunosensor for the detection of aflatoxin B₁ (AFB₁) was successfully developed based on an indirect competitive enzyme-linked immunosorbent assay (ELISA). Various parameters of ELISA, including antigen⁻antibody concentration, blocking agents, incubation time, temperature and pH of reagents, were first optimized in a 96-well microtiter plate to study the antigen⁻antibody interaction and optimize the optimum parameters of the assay. The optimized assay was transferred onto the multi-walled carbon nanotubes/chitosan/screen-printed carbon electrode (MWCNTs/CS/SPCE) by covalent attachment with the aid of 1-Ethyl-3-(3-dimetylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Competition occurred between aflatoxin B₁-bovine serum albumin (AFB₁⁻BSA) and free AFB₁ (in peanut sample and standard) for the binding site of a fixed amount of anti-AFB₁ antibody. Differential pulse voltammetry (DPV) analysis was used for the detection based on the reduction peak of TMB(ox). The developed immunosensor showed a linear range of 0.0001 to 10 ng/mL with detection limit of 0.3 pg/mL. AFB₁ analysis in spiked peanut samples resulted in recoveries between 80% and 127%. The precision of the developed immunosensor was evaluated by RSD values (n = 5) as 4.78% and 2.71% for reproducibility and repeatability, respectively.

Matched MeSH terms: Antibodies/immunology
Generation of a naïve human single chain variable fragment (scFv) library for the identification of monoclonal scFv against Salmonella Typhi Hemolysin E antigen

Lim BN, Chin CF, Choong YS, Ismail A, Lim TS

Toxicon, 2016 Jul;117:94-101.
PMID: 27090555 DOI: 10.1016/j.toxicon.2016.04.032

Antibody phage display is a useful tool for the isolation and identification of monoclonal antibodies. Naive antibody libraries are able to overcome the limitations associated with the traditional hybridoma method for monoclonal antibody generation. Antibody phage display is also a preferred method for antibody generation against toxins as it does not suffer from toxicity mediated complications. Here, we describe a naïve multi ethnic scFv antibody library generated via two-step cloning with an estimated diversity of 2 × 10(9). The antibody library was used to screen for monoclonal antibodies against Hemolysin E antigen, a pore forming toxin produced by Salmonella enterica serovar Typhi. A soluble monoclonal scFv antibody against the HlyE toxin (IgM scFv D7 anti-hlyE) was isolated from the library. This shows the value of the naïve library to generate antibodies against toxin targets in addition to the potential use of the library to isolate antibodies against other immunogenic targets.

Matched MeSH terms: Single-Chain Antibodies/immunology*
Fulltext Acquired haemophilia--a therapeutic challenge

Teh A, Leong KW, Bosco JJ, Koong PL, Jayaranee S

Med J Malaysia, 1995 Jun;50(2):166-70.
PMID: 7565188

Acquired haemophilia is a rare clinical condition arising from the spontaneous development of inhibitors to factor VIII. We describe two cases encountered in the University Hospital over the past five years. We also review the literature and discuss the therapeutic difficulties faced in dealing with patients with high levels of inhibitors. In one of these patients we also describe, for the first time in this region, a novel method in managing the acute bleeding episode in acquired haemophilia using recombinant factor VIIa.

Matched MeSH terms: Antibodies/immunology
Diagnostic performance of anti-RA33 antibody as a serological marker for rheumatoid arthritis

Syed Mohamed Suhail SM, Nur Atiqah I, Nur Salimi Zakirah ZA, Lailatul Syazwani Z, Batis WW, Md Monoto EM, et al.

Malays J Pathol, 2019 Dec;41(3):259-265.
PMID: 31901910

INTRODUCTION: Rheumatoid arthritis is diagnosed based on the 2010 Rheumatoid Arthritis Classification Criteria whereby rheumatoid factor and anti-citrullinated protein antibody are the serological markers included in these criteria. Anti-RA33 antibody has the potential to provide additional diagnostic value in rheumatoid arthritis. The aim of this study is to determine the diagnostic performance of anti-RA33 antibody as a serological marker for rheumatoid arthritis.
MATERIAL AND METHODS: Thirtyfour patients with rheumatoid arthritis and 34 non-rheumatoid arthritis individuals were included in this cross-sectional study. Anti-RA33 antibody and rheumatoid factor were performed on all samples.
RESULTS: The sensitivity, specificity, positive and negative predictive value for anti-RA33 antibody and rheumatoid factor were 41.1%, 97.1%, 93.3%, 62.3% and 64.7%, 79.4%, 75.9%, 69.2% respectively. The overall sensitivity and specificity if either anti-RA33 antibody or rheumatoid factor are positive were 79.4% and 76.47% respectively.
CONCLUSION: Anti-RA33 antibody showed good specificity and positive predictive value and could be considered as a potential serological marker for rheumatoid arthritis diagnosis.

Matched MeSH terms: Antibodies/immunology
Fulltext Chronic hepatitis C infection associated with neuromyelitis optica and antinuclear antibodies

Earnest BS, Men LC, Sukvinder Kaur G, Alias RB, Sunita Devi H

J Assoc Physicians India, 2010 Feb;58(2):118-20.
PMID: 20653157

The neurological manifestations of chronic hepatitis C is most often a peripheral sensory neuropathy characterised by numbness, burning and sensation of "pins and needles". Peripheral motor neuropathy, mononeuropathy, mononeuropathy multiplex and transverse myelitis also occur. Ischemic stroke and transient cerebral ischemia have also been reported. Anterior ischemic optic neuropathy is seen, often following interferon therapy. We report an exceptional case of neuromyelitis optica in chronic hepatitis C infection in the absence of interferon therapy.

Matched MeSH terms: Hepatitis C Antibodies/immunology*
Positive Hepatitis B Core Antibody Is Associated With Cirrhosis and Hepatocellular Carcinoma in Nonalcoholic Fatty Liver Disease

Chan TT, Chan WK, Wong GL, Chan AW, Nik Mustapha NR, Chan SL, et al.

Am J Gastroenterol, 2020 06;115(6):867-875.
PMID: 32149781 DOI: 10.14309/ajg.0000000000000588

OBJECTIVES: Previous exposure to hepatitis B virus (HBV) may increase the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis C. We aim to study the impact of previous HBV infection on the severity and outcomes of patients with nonalcoholic fatty liver disease (NAFLD).
METHODS: This was a multicenter study of 489 patients with biopsy-proven NAFLD and 69 patients with NAFLD-related or cryptogenic HCC. Antihepatitis B core antibody (anti-HBc) was used to detect the previous HBV infection.
RESULTS: In the biopsy cohort, positive anti-HBc was associated with lower steatosis grade but higher fibrosis stage. 18.8% and 7.5% of patients with positive and negative anti-HBc had cirrhosis, respectively (P < 0.001). The association between anti-HBc and cirrhosis remained significant after adjusting for age and metabolic factors (adjusted odds ratio 2.232; 95% confidence interval, 1.202-4.147). At a mean follow-up of 6.2 years, patients with positive anti-HBc had a higher incidence of HCC or cirrhotic complications (6.5% vs 2.2%; P = 0.039). Among patients with NAFLD-related or cryptogenic HCC, 73.9% had positive anti-HBc. None of the patients had positive serum HBV DNA. By contrast, antihepatitis B surface antibody did not correlate with histological severity.
DISCUSSION: Positive anti-HBc is associated with cirrhosis and possibly HCC and cirrhotic complications in patients with NAFLD. Because a significant proportion of NAFLD-related HCC may develop in noncirrhotic patients, future studies should define the role of anti-HBc in selecting noncirrhotic patients with NAFLD for HCC surveillance.

Matched MeSH terms: Hepatitis B Antibodies/immunology*
Fulltext Broad specificity of immune helminth scFv library to identify monoclonal antibodies targeting Strongyloides

Rahumatullah A, Balachandra D, Noordin R, Baharudeen Z, Lim YY, Choong YS, et al.

Sci Rep, 2021 01 28;11(1):2502.
PMID: 33510342 DOI: 10.1038/s41598-021-82125-3

Antibodies have different chemical properties capable of targeting a diverse nature of antigens. Traditionally, immune antibody libraries are perceived to be disease-specific with a skewed repertoire. The complexity during the generation of a combinatorial antibody library allows for a skewed but diverse repertoire to be generated. Strongyloides stercoralis is a parasite that causes strongyloidiasis, a potentially life-threatening disease with a complex diagnosis that impedes effective control and treatment of the disease. This study describes the isolation of monoclonal antibodies against S. stercoralis NIE recombinant protein using an immune antibody phage display library derived from lymphatic filaria-infected individuals. The isolated antibody clones showed both lambda and kappa light chains gene usage, with diverse amino acid distributions. Structural analysis showed that electropositivity and the interface area could determine the binding affinity of the clones with NIE. The successful identification of S. stercoralis antibodies from the filarial immune library highlights the breadth of antibody gene diversification in an immune antibody library that can be applied for closely related infections.

Matched MeSH terms: Single-Chain Antibodies/immunology*
Fulltext Development of a Phage Display Panning Strategy Utilizing Crude Antigens: Isolation of MERS-CoV Nucleoprotein human antibodies

Lim CC, Woo PCY, Lim TS

Sci Rep, 2019 Apr 15;9(1):6088.
PMID: 30988390 DOI: 10.1038/s41598-019-42628-6

Antibody phage display has been pivotal in the quest to generate human monoclonal antibodies for biomedical and research applications. Target antigen preparation is a main bottleneck associated with the panning process. This includes production complexity, downstream purification, quality and yield. In many instances, purified antigens are preferred for panning but this may not be possible for certain difficult target antigens. Here, we describe an improved procedure of affinity selection against crude or non-purified antigen by saturation of non-binders with blocking agents to promote positive binder enrichment termed as Yin-Yang panning. A naïve human scFv library with kappa light chain repertoire with a library size of 109 was developed. The improved Yin-Yang biopanning process was able to enrich monoclonal antibodies specific to the MERS-CoV nucleoprotein. Three unique monoclonal antibodies were isolated in the process. The Yin-Yang biopanning method highlights the possibility of utilizing crude antigens for the isolation of monoclonal antibodies by phage display.

Matched MeSH terms: Single-Chain Antibodies/immunology
Fulltext Highly specific antibodies for co-detection of human choline kinase α1 and α2 isoforms

Too WC, Wong MT, Few LL, Konrad M

PLoS One, 2010;5(9):e12999.
PMID: 20886003 DOI: 10.1371/journal.pone.0012999

Choline kinase is the first enzyme in the CDP-choline pathway that synthesizes phosphatidylcholine, the major phospholipid in eukaryotic cell membranes. In humans, choline kinase exists as three isoforms (CKα1, α2, and β). Specific inhibition of CKα has been reported to selectively kill tumoral cells. Monoclonal and polyclonal antibodies against CKα used in previous studies to detect the level of this isozyme in different cellular or biochemical contexts were able to detect either the α1 or the α2 isoform.

Matched MeSH terms: Antibodies/immunology
Fulltext Molecular endoscopic imaging for the detection of Barrett's metaplasia using biodegradable inorganic nanoparticles: An ex-vivo pilot study on human tissue

Ahmed S, Kreft A, Chowdhury EH, Hossain SM, Galle PR, Neumann H

PLoS One, 2020;15(10):e0239814.
PMID: 33002048 DOI: 10.1371/journal.pone.0239814

BACKGROUND AND STUDY AIMS: Despite major technical advancements, endoscopic surveillance for detecting premalignant lesions in Barrett's esophagus is challenging because of their flat appearance with only subtle morphological changes. Molecular endoscopic imaging (MEI) using nanoparticles (NPs), coupled with fluorescently labeled antibody permits visualization of disease-specific molecular alterations. The aim of this ex vivo study was to assess the diagnostic applicability of MEI with NPs to detect Barrett's metaplasia.
PATIENTS AND METHODS: Seven patients undergoing endoscopic surveillance of known Barrett's esophagus were recruited. Freshly resected biopsy specimens were incubated with NPs coupled with FITC labeled Muc-2 antibodies and examined with MEI. Fluorescence intensity from Barrett's mucosa and control specimens were compared, followed by histological confirmation.
RESULTS: Fluorescence signals, indicating the presence of goblet cells, were noted for traditional MEI using Muc-2 antibodies in Barrett's intestinal metaplasia. Significantly stronger fluorescence signals were achieved with NPs coupled with FITC-conjugated Muc-2 antibodies. The results of MEI with NPs for the prediction of Barrett's metaplasia correlated with the final histopathological examination in all the cases.
CONCLUSIONS: Highly-specific NPs detected Barrett's metaplasia more efficiently than conventional MEI in this first feasibility study. MEI was as effective as standard histopathology for identifying Muc-2 containing goblet cells for diagnosis of Barrett's metaplasia. (DRKS-ID: DRKS00017747).

Matched MeSH terms: Antibodies/immunology
L-arginine-dependent nitric oxide production of a murine macrophage-like RAW 264.7 cell line stimulated with Porphyromonas gingivalis lipopolysaccharide

Sosroseno W, Herminajeng E, Bird PS, Seymour GJ

Oral Microbiol. Immunol., 2004 Apr;19(2):65-70.
PMID: 14871343

The aim of this study was to determine nitric oxide (NO) production of a murine macrophage cell line (RAW 264.7 cells) when stimulated with Porphyromonas gingivalis lipopolysaccharides (Pg-LPS). RAW 264.7 cells were incubated with i) various concentrations of Pg-LPS or Salmonella typhosa LPS (St-LPS), ii) Pg-LPS with or without L-arginine and/or NG-monomethyl-L-arginine (NMMA), an arginine analog or iii) Pg-LPS and interferon-gamma (IFN-gamma) with or without anti-IFN-gamma antibodies or interleukin-10 (IL-10). Tissue culture supernatants were assayed for NO levels after 24 h in culture. NO was not observed in tissue culture supernatants of RAW 264.7 cells following stimulation with Pg-LPS, but was observed after stimulation with St-LPS. Exogenous L-arginine restored the ability of Pg-LPS to induce NO production; however, the increase in NO levels of cells stimulated with Pg-LPS with exogenous L-arginine was abolished by NMMA. IFN-gamma induced independent NO production by Pg-LPS-stimulated macrophages and this stimulatory effect of IFN-gamma could be completely suppressed by anti-IFN-gamma antibodies and IL-10. These results suggest that Pg-LPS is able to stimulate NO production in the RAW 264.7 macrophage cell model in an L-arginine-dependent mechanism which is itself independent of the action of IFN-gamma.

Matched MeSH terms: Antibodies/immunology
Fulltext Generation of High Affinity Anti-Peptide Polyclonal Antibodies Recognizing Goat αs1-Casein

Mohsin AZ, Sukor R, Selamat J, Meor Hussin AS, Ismail IH, Jambari NN, et al.

Molecules, 2020 Jun 05;25(11).
PMID: 32516919 DOI: 10.3390/molecules25112622

The chemical, technological and allergy properties of goat's milk are significantly affected by the level of αs1-casein. Detection and quantification of αs1-casein requires high-specificity methods to overcome high-sequence similarity between this protein and others in the casein family. Unavailability of antibodies with high affinity and specificity towards goat αs1-casein hinders the development of immuno-based analytical methods such as enzyme-linked immunosorbent assay (ELISA) and biosensors. Here, we report the generation of polyclonal antibodies (or immunoglobulins, IgGs) raised towards goat αs1-casein N- (Nter) and C-terminal (Cter) peptide sequences. The Nter and Cter peptides of goat αs1-casein were immunized in rabbits for the generation of antisera, which were purified using protein G affinity chromatography. The binding affinity of the antisera and purified IgGs were tested and compared using indirect ELISA, where peptide-BSA conjugates and goat αs1-casein were used as the coating antigens. The Nter antiserum displayed higher titer than Cter antiserum, at 1/64,000 and 1/32,000 dilutions, respectively. The purification step further yielded 0.5 mg/mL of purified IgGs from 3 mL of antisera. The purified Nter IgG showed a significantly (p < 0.05) higher binding affinity towards peptide-BSA and goat αs1-casein, with lower Kd value at 5.063 × 10-3 μM compared to 9.046 × 10-3 μM for the Cter IgG. A cross-reactivity test showed that there was no binding in neither Nter nor Cter IgGs towards protein extracts from the milk of cow, buffalo, horse and camel. High-quality antibodies generated will allow further development of immuno-based analytical methods and future in vitro studies to be conducted on goat αs1-casein.

Matched MeSH terms: Antibodies/immunology*
Delineation of BmSXP antibody V-gene usage from a lymphatic filariasis based immune scFv antibody library

Rahumatullah A, Ahmad A, Noordin R, Lim TS

Mol Immunol, 2015 Oct;67(2 Pt B):512-23.
PMID: 26277276 DOI: 10.1016/j.molimm.2015.07.040

Phage display technology is an important tool for antibody generation or selection. This study describes the development of a scFv library and the subsequent analysis of identified monoclonal antibodies against BmSXP, a recombinant antigen for lymphatic filariasis. The immune library was generated from blood of lymphatic filariasis infected individuals. A TA based intermediary cloning approach was used to increase cloning efficiency for the library construction process. A diverse immune scFv library of 10(8) was generated. Six unique monoclonal antibodies were identified from the 50 isolated clones against BmSXP. Analysis of the clones showed a bias for the IgHV3 and Vκ1 (45.5%) and IgHV2 and Vκ3 (27.3%) gene family. The most favored J segment for light chain is IgKJ1 (45.5%). The most favored D and J segment for heavy chain are IgHD6-13 (75%) and IgHJ3 (47.7%). The information may suggest a predisposition of certain V genes in antibody responses against lymphatic filariasis.

Matched MeSH terms: Single-Chain Antibodies/immunology*
Development and structural characterisation of human scFv targeting MDM2 spliced variant MDM215kDa

Lim CC, Chan SK, Lim YY, Ishikawa Y, Choong YS, Nagaoka Y, et al.

Mol Immunol, 2021 07;135:191-203.
PMID: 33930714 DOI: 10.1016/j.molimm.2021.04.016

The murine double minute 2 (MDM2) protein is a major negative regulator of the tumour suppressor protein p53. Under normal conditions, MDM2 constantly binds to p53 transactivation domain and/or ubiquinates p53 via its role as E3 ubiquitin ligase to promote p53 degradation as well as nuclear export to maintain p53 levels in cells. Meanwhile, amplification of MDM2 and appearance of MDM2 spliced variants occur in many tumours and normal tissues making it a prognostic indicator for human cancers. The mutation or deletion of p53 protein in half of human cancers inactivates its tumour suppressor activity. However, cancers with wild type p53 have its function effectively inhibited through direct interaction with MDM2 oncoprotein. Here, we described the construction of a MDM2 spliced variant (rMDM215kDa) consisting of SWIB/MDM2 domain and its central region for antibody generation. Biopanning with a human naïve scFv library generated four scFv clones specific to rMDM215kDa. Additionally, the selected scFv clones were able to bind to the recombinant full length MDM2 (rMDM2-FL). Computational prediction showed that the selected scFv clones potentially bind to exon 7-8 of MDM2 while leaving the MDM2/SWIB domain free for p53 interaction. The developed antibodies exhibit good specificity can be further investigated for downstream biomedical and research applications.

Matched MeSH terms: Single-Chain Antibodies/immunology*
Divalent ion-induced aggregation of gold nanoparticles for voltammetry Immunosensing: comparison of transducer signals in an assay for the squamous cell carcinoma antigen

Letchumanan I, Gopinath SCB, Arshad MKM

Mikrochim Acta, 2020 01 14;187(2):128.
PMID: 31938893 DOI: 10.1007/s00604-020-4115-0

A method is described for the electrochemical determination of squamous cell carcinoma (SCC) antigen, and by testing the effect of 30 nm gold nanoparticles (GNPs). Three comparative studies were performed in the presence and absence of GNPs, and with agglomerated GNPs. The divalent ion Ca(II) was used to induce a strong agglomeration of GNPs, as confirmed by colorimetry and voltammetry. Herein, colorimetry was used to test the best amount of salt needed to aggregate the GNPs. Despite, voltammetry was used to determine the status of biomolecules on the sensor. The topography of the surface of ZnO-coated interdigitated electrodes was analyzed by using 3D-nano profilometry, scanning electron microscopy, atomic force microscopy and high-power microscopy. The interaction between SCC antigen and antibody trigger vibrations on the sensor and cause dipole moment, which was measured using a picoammeter with a linear sweep from 0 to 2 V at 0.01 V step voltage. The sensitivity level was 10 fM by 3σ calculation for the dispersed GNP-conjugated antigen. This indicates a 100-fold enhancement compared to the condition without GNP conjugation. However, the sensitivity level for agglomerated GNPs conjugated antibody was not significant with 100 fM sensitivity. Specificity was tested for other proteins in serum, namely blood clotting factor IX, C-reactive protein, and serum albumin. The SCC antigen was quantified in spiked serum and gave recoveries that ranged between 80 and 90%. Graphical abstractSchematic representation of SCC (squamous cell carcinoma) antigen determination using divalent ion induced agglomerated GNPs. Sensitivity increment depends on the occurrence of more SCC antigen and antibody binding event via GNPs integration. Notably, lower detection limit was achieved at femto molar with proper orientation of biological molecules.

Matched MeSH terms: Antibodies/immunology
Mass Spectrometry Immuno Assay (MSIA™) Streptavidin Disposable Automation Research Tips (D.A.R.T's®) Antibody Phage Display Biopanning

Chin CF, Choong YS, Lim TS

Methods Mol Biol, 2018;1701:285-299.
PMID: 29116511 DOI: 10.1007/978-1-4939-7447-4_15

Antibody phage display has been widely established as the method of choice to generate monoclonal antibodies with various efficacies post hybridoma technology. This technique is a popular method which takes precedence over ease of methodology, time- and cost-savings with comparable outcomes to conventional methods. Phage display technology manipulates the genome of M13 bacteriophage to display large diverse collection of antibodies that is capable of binding to various targets (nucleic acids, peptides, proteins, and carbohydrates). This subsequently leads to the discovery of target-related antibody binders. There have been several different approaches adapted for antibody phage display over the years. This chapter focuses on the semi-automated phage display antibody biopanning method utilizing the MSIA™ streptavidin D.A.R.T's® system. The system employs the use of electronic multichannel pipettes with predefined programs to carry out the panning process. The method should also be adaptable to larger liquid handling instrumentations for higher throughput.

Matched MeSH terms: Single-Chain Antibodies/immunology
The design of target specific antibodies (scFv) by applying de novo workflow: Case study on BmR1 antigen from Brugia malayi

Khor BY, Lim TS, Noordin R, Choong YS

J Mol Graph Model, 2017 09;76:543-550.
PMID: 28811153 DOI: 10.1016/j.jmgm.2017.07.004

De novo approach was applied to design single chain fragment variable (scFv) for BmR1, a recombinant antigen from Bm17DIII gene which is the primary antigen used for the detection of anti-BmR1 IgG4 antibodies in the diagnostic of lymphatic filariasis. Three epitopes of the BmR1 was previously predicted form an ab initio derived three-dimensional structure. A collection of energetically favourable conformations was generated via hot-spot-centric approach. This resulted in a set of three different scFv scaffolds used to compute the high shape complementary conformations via dock-and-design approach with the predicted epitopes of BmR1. A total of 4227 scFv designs were generated where 200 scFv designs produced binding energies of less than -20 R.E.U with shape complementarity higher than 0.5. We further selected the design with at least one hydrogen bond and one salt bridge with the epitope, thus resulted in a total of 10, 1 and 19 sFv designs for epitope 1, 2 and 3, respectively. The results thus showed that de novo design can be an alternative approach to yield high affinity in silico scFv designs as a starting point for antibody or specific binder discovery processes.

Matched MeSH terms: Single-Chain Antibodies/immunology

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