MyMedR

Displaying publications 121 - 140 of 289 in total

Abstract:

Sort:

Overexpression, purification and validation of antigenic Salmonella enterica serovar Typhi proteins identified from LC-MS/MS

Chin CF, Teh BA, Anthony AA, Aziah I, Ismail A, Ong EB, et al.

Appl Biochem Biotechnol, 2014 Nov;174(5):1897-906.
PMID: 25149461 DOI: 10.1007/s12010-014-1173-y

In our earlier study, an immunoblot analysis using sera from febrile patients revealed that a 50-kDa band from an outer membrane protein fraction of Salmonella enterica serovar Typhi was specifically recognized only by typhoid sera and not sera from other febrile illnesses. Here, we investigated the identities of the proteins contained in the immunogenic 50-kDa band to pinpoint antigens responsible for its immunogenicity. We first used LC-MS/MS for protein identification, then used the online tool ANTIGENpro for antigenicity prediction and produced recombinant proteins of the lead antigens for validation in an enzyme-linked immunosorbent assay (ELISA). We found that proteins TolC, GlpK and SucB were specific to typhoid sera but react to antibodies differently under native and denatured conditions. This difference suggests the presence of linear and conformational epitopes on these proteins.

Matched MeSH terms: Bacterial Outer Membrane Proteins/immunology*
Fulltext Production and characterization of a polyclonal antibody of anti-rLipL21-IgG against leptospira for early detection of acute leptospirosis

Seenichamy A, Bahaman AR, Mutalib AR, Khairani-Bejo S

Biomed Res Int, 2014;2014:592858.
PMID: 24860824 DOI: 10.1155/2014/592858

Leptospirosis is one of the zoonotic diseases in animals and humans throughout the world. LipL21 is one of the important surface-exposed lipoproteins in leptospires and the most effective cross protective immunogenic antigen. It is widely considered as a diagnostic marker for leptospirosis. In this study, we evaluated the serodiagnostic potential of LipL21 protein of Leptospira interrogans serovar Pomona. We have successfully amplified, cloned, and expressed LipL21 in E. coli and evaluated its specificity by immunoblotting. Purified recombinant LipL21 (rLipL21) was inoculated into rabbits for the production of polyclonal antibody. Characterization of the purified IgG antibody against rLipL21 was performed by cross reactivity assay. Only sera from leptospirosis patients and rabbit hyperimmune sera recognized rLipL21 while the nonleptospirosis control sera showed no reaction in immunoblotting. We confirmed that anti-rLipL21-IgG antibody cross reacted with and detected only pathogenic leptospiral species and it did not react with nonpathogenic leptospires and other bacterial species. Results observed showed that anti-rLipL21-IgG antibody has high specificity and sensitivity to leptospires. The findings indicated that the antibody could be used in a diagnostic assay for detection of leptospires or their proteins in the early phase of infection.

Matched MeSH terms: Ribosomal Proteins/immunology*
Fulltext Mucosal genetic immunization through microsphere-based oral carriers

Rosli R, Nograles N, Hanafi A, Nor Shamsudin M, Abdullah S

Hum Vaccin Immunother, 2013 Oct;9(10):2222-7.
PMID: 24051430 DOI: 10.4161/hv.25325

Polymeric carriers in the form of cellulose acetate phthalate (CAP) and alginate (ALG) microspheres were used for encapsulation of plasmid DNA for oral mucosal immunization. Access into the intestinal mucosa by pVAX1 eukaryotic expression plasmid vectors carrying gene-coding sequences, either for the cholera enterotoxin B subunit (ctxB) immunostimulatory antigen or the green fluorescent protein (GFP), delivered from both types of microsphere carriers were examined in orally immunized BALB/c mice. Demonstration of transgene protein expression and IgA antibody responses at local mucosal sites suggest immunological response to a potential oral DNA vaccine formulated within the microsphere carriers.

Matched MeSH terms: Green Fluorescent Proteins/immunology
Fulltext Potential immunogenic polypeptides of Burkholderia pseudomallei identified by shotgun expression library and evaluation of their efficacy for serodiagnosis of melioidosis

Puah SM, Puthucheary SD, Chua KH

Int J Med Sci, 2013;10(5):539-47.
PMID: 23532805 DOI: 10.7150/ijms.5516

The search for novel immunogenic polypeptides to improve the accuracy and reliability of serologic diagnostic methods for Burkholderia pseudomallei infection is ongoing. We employed a rapid and efficient approach to identify such polypeptides with sera from melioidosis patients using a small insert genomic expression library created from clinically confirmed local virulent isolates of B. pseudomallei. After 2 rounds of immunoscreening, 6 sero-positive clones expressing immunogenic peptides were sequenced and their identities were: benzoate 1,2-dioxygenase beta subunit, a putative 200 kDa antigen p200, phosphotransferase enzyme family protein, short chain dehydrogenase and 2 hypothetical proteins. These immunogens were then transferred to an ELISA platform for further large scale screening. By combining shotgun expression library and ELISA assays, we identified 2 polypeptides BPSS1904 (benzoate 1,2-dioxygenase beta subunit) and BPSL3130 (hypothetical protein), which had sensitivities of 78.9% and 79.4% and specificities of 88.1% and 94.8%, respectively in ELISA test, thus suggesting that both are potential candidate antigens for the serodiagnosis of infections caused by B. pseudomallei.

Matched MeSH terms: Bacterial Proteins/immunology*
Fulltext Immunization with recombinant enterovirus 71 viral capsid protein 1 fragment stimulated antibody responses in hamsters

Ch'ng WC, Stanbridge EJ, Wong KT, Ong KC, Yusoff K, Shafee N

Virol J, 2012;9:155.
PMID: 22877087 DOI: 10.1186/1743-422X-9-155

Enterovirus 71 (EV71) causes severe neurological diseases resulting in high mortality in young children worldwide. Development of an effective vaccine against EV71 infection is hampered by the lack of appropriate animal models for efficacy testing of candidate vaccines. Previously, we have successfully tested the immunogenicity and protectiveness of a candidate EV71 vaccine, containing recombinant Newcastle disease virus capsids that display an EV71 VP1 fragment (NPt-VP11-100) protein, in a mouse model of EV71 infection. A drawback of this system is its limited window of EV71 susceptibility period, 2 weeks after birth, leading to restricted options in the evaluation of optimal dosing regimens. To address this issue, we have assessed the NPt-VP11-100 candidate vaccine in a hamster system, which offers a 4-week susceptibility period to EV71 infection. Results obtained showed that the NPt-VP11-100 candidate vaccine stimulated excellent humoral immune response in the hamsters. Despite the high level of antibody production, they failed to neutralize EV71 viruses or protect vaccinated hamsters in viral challenge studies. Nevertheless, these findings have contributed towards a better understanding of the NPt-VP11-100 recombinant protein as a candidate vaccine in an alternative animal model system.

Matched MeSH terms: Capsid Proteins/immunology*
Fulltext scFv antibody: principles and clinical application

Ahmad ZA, Yeap SK, Ali AM, Ho WY, Alitheen NB, Hamid M

Clin. Dev. Immunol., 2012;2012:980250.
PMID: 22474489 DOI: 10.1155/2012/980250

To date, generation of single-chain fragment variable (scFv) has become an established technique used to produce a completely functional antigen-binding fragment in bacterial systems. The advances in antibody engineering have now facilitated a more efficient and generally applicable method to produce Fv fragments. Basically, scFv antibodies produced from phage display can be genetically fused to the marker proteins, such as fluorescent proteins or alkaline phosphatase. These bifunctional proteins having both antigen-binding capacity and marker activity can be obtained from transformed bacteria and used for one-step immunodetection of biological agents. Alternatively, antibody fragments could also be applied in the construction of immunotoxins, therapeutic gene delivery, and anticancer intrabodies for therapeutic purposes. This paper provides an overview of the current studies on the principle, generation, and application of scFv. The potential of scFv in breast cancer research is also discussed in this paper.

Matched MeSH terms: Recombinant Fusion Proteins/immunology
Investigating membrane morphology and quantity of immobilized protein for the development of lateral flow immunoassay

Ahmad AL, Low SC, Shukor SR, Ismail A

J Immunoassay Immunochem, 2012 Jan;33(1):48-58.
PMID: 22181820 DOI: 10.1080/15321819.2011.591479

This study was aimed at gaining a quantitative understanding of the effect of protein quantity and membrane pore structure on protein immobilization. The concentration of immobilized protein was measured by staining with Ponceau S and measuring its color intensity. In this study, both membrane morphology and the quantity of deposited protein significantly influenced the quantity of protein immobilization on the membrane surface. The sharpness and intensity of the red protein spots varied depending on the membrane pore structure, indicating a dependence of protein immobilization on this factor. Membranes with smaller pores resulted in a higher color density, corresponding to enhanced protein immobilization and an increased assay sensitivity level. An increased of immobilized volume has a significant jagged outline on the protein spot but, conversely, no difference in binding capacity.

Matched MeSH terms: Immobilized Proteins/immunology
Can the acute-phase reactant proteins be used as cancer biomarkers?

Pang WW, Abdul-Rahman PS, Wan-Ibrahim WI, Hashim OH

Int. J. Biol. Markers, 2010 Jan-Mar;25(1):1-11.
PMID: 20155712

The association between the acute-phase reactant proteins (APRPs) and cancer has long been established. There have been numerous reports correlating altered levels of various APRPs with different types of cancers. However, researchers are often quick to dismiss the use of these APRPs as potential biomarkers for the diagnosis and monitoring of cancer because alterations in APRP concentrations are observed in a wide range of diseases. Recent progress in proteomics studies which profiled the serum proteins of cancer patients and those of normal individuals indicated that the altered APRP expressions were different for distinct types, subtypes, and even stages of cancer. Interestingly, these data are in agreement with those observed earlier using immunochemical and biochemical assays. In view of this compelling association of different patterns of APRPs with various types of cancers and in an apparent shift of paradigm, we present in this review some indications that APRP fingerprinting may be used as complementary cancer biomarkers.

Matched MeSH terms: Acute-Phase Proteins/immunology
Fulltext Immunogenic Burkholderia pseudomallei outer membrane proteins as potential candidate vaccine targets

Hara Y, Mohamed R, Nathan S

PLoS One, 2009 Aug 05;4(8):e6496.
PMID: 19654871 DOI: 10.1371/journal.pone.0006496

BACKGROUND: Burkholderia pseudomallei is the causative agent of melioidosis, a disease of significant morbidity and mortality in both human and animals in endemic areas. There is no vaccine towards the bacterium available in the market, and the efficacy of many of the bacterium's surface and secreted proteins are currently being evaluated as vaccine candidates.
METHODOLOGY/PRINCIPAL FINDINGS: With the availability of the B. pseudomallei whole genome sequence, we undertook to identify genes encoding the known immunogenic outer membrane protein A (OmpA). Twelve OmpA domains were identified and ORFs containing these domains were fully annotated. Of the 12 ORFs, two of these OmpAs, Omp3 and Omp7, were successfully cloned, expressed as soluble protein and purified. Both proteins were recognised by antibodies in melioidosis patients' sera by Western blot analysis. Purified soluble fractions of Omp3 and Omp7 were assessed for their ability to protect BALB/c mice against B. pseudomallei infection. Mice were immunised with either Omp3 or Omp7, subsequently challenged with 1x10(6) colony forming units (cfu) of B. pseudomallei via the intraperitoneal route, and examined daily for 21 days post-challenge. This pilot study has demonstrated that whilst all control unimmunised mice died by day 9 post-challenge, two mice (out of 4) from both immunised groups survived beyond 21 days post-infection.
CONCLUSIONS/SIGNIFICANCE: We have demonstrated that B. pseudomallei OmpA proteins are immunogenic in mice as well as melioidosis patients and should be further assessed as potential vaccine candidates against B. pseudomallei infection.

Matched MeSH terms: Bacterial Outer Membrane Proteins/immunology*
Identification of the major allergens of Charybdis feriatus (red crab) and its cross-reactivity with Portunus pelagicus (blue crab)

Misnan R, Murad S, Yadzir ZH, Abdullah N

Asian Pac J Allergy Immunol, 2012 Dec;30(4):285-93.
PMID: 23393908

Tropomyosin and arginine kinase have been identified as the major allergens in multiple species of crab. Charybdis feriatus is an important commercial crab in this country.

Matched MeSH terms: Arthropod Proteins/immunology*
Low prevalence of latex sensitivity in South African spina bifida children in Cape Town

Johar A, Lim DL, Arif SA, Hawarden D, Toit GD, Weinberg EG, et al.

Pediatr Allergy Immunol, 2005 Mar;16(2):165-70.
PMID: 15787875

Spina bifida children have a high prevalence of latex allergy in studies reported from Europe and the USA. This study investigated the prevalence of latex allergy in a cohort of 24 spina bifida children at the Red Cross Children's Hospital from Cape Town, South Africa. The children were investigated using a detailed questionnaire, skin prick tests (ALK-Abello), ImmunoCap RASTs, Western blotting and ELISA, using the purified latex proteins Hev b1 and Hev b3 and whole latex preparation. A low overall prevalence of latex sensitization of 16.7% was found in the children. Children who were sensitive reacted to water insoluble to Hev b1 and Hev b3 proteins. The low prevalence of latex sensitization in the South African children may not be entirely explained by stringent latex avoidance. The children were from a low socioeconomic social status and 'hygiene' and other factors should be considered.

Matched MeSH terms: Plant Proteins/immunology
Fulltext Dengue patients exhibit higher levels of PrM and E antibodies than their asymptomatic counterparts

Yeo AS, Rathakrishnan A, Wang SM, Ponnampalavanar S, Manikam R, Sathar J, et al.

Biomed Res Int, 2015;2015:420867.
PMID: 25815314 DOI: 10.1155/2015/420867

Dengue virus infection is a common tropical disease which often occurs without being detected. These asymptomatic cases provide information in relation to the manifestation of immunological aspects. In this study, we developed an ELISA method to compare neutralizing effects of dengue prM and E antibodies between dengue patients and their asymptomatic household members. Recombinant D2 premembrane (prM) was constructed, cloned, and tested for antigenicity. The recombinant protein was purified and tested with controls by using an indirect ELISA method. Positive dengue serum samples with their asymptomatic pair were then carried out onto the developed ELISA. In addition, commercially available recombinant envelope (E) protein was used to develop an ELISA which was tested with the same set of serum samples in the prM ELISA. Asymptomatic individuals showed preexisting heterotypic neutralizing antibodies. The recombinant prM was antigenically reactive in the developed ELISA. Dengue patients had higher prM and E antibodies compared to their household members. Our study highlights the neutralizing antibodies levels with respect to dengue prM and E between dengue patients and asymptomatic individuals.

Matched MeSH terms: Recombinant Proteins/immunology
Appraisal of latex glove proteins in the induction of sensitivity to multiple latex allergens

Yeang HY, Chow KS, Yusof F, Arif SA, Chew NP, Loke YH

J Investig Allergol Clin Immunol, 2000 Jul-Aug;10(4):215-22.
PMID: 11039838

Six Hevea brasiliensis latex protein allergens, Hevb 1, Hev b 2, Hev b 3, Hev b 4, and two variants of Hev b 7 (7b and 7c), were purified from Hevea latex, while a seventh protein, Hev b 5, was prepared in recombinant form. The presence of these proteins in glove extracts was indicated by their respective antibodies in the serum of rabbits immunized against the extracts. The relative propensities of IgE binding to the individual latex allergens were compared using sera from latex-allergic patients. IgE recognition of Hev b 4, Hev b 7b, Hev b 5 and Hev b 2 was most frequently encountered, with 75, 61, 31 and 28%, respectively, of the patient sera reacting. Sensitivity to multiple latex proteins was common, and out of the 31 seropositive patients, 23 (74%/ ) had IgE against at least two latex allergens, while 12 (39%) had IgE specific for at least three allergens. Statistical analysis of the data suggested that many patients might have acquired sensitivity to Hev b 2, Hev b 4 and Hev b 7b from a common source. (e.g., from latex products). On the other hand, sensitivity to Hev b 5 and to Hev b 7c were interrelated. It is plausible that sensitivity to these two proteins might have been acquired from sources other than latex products (e.g., from certain foods).

Matched MeSH terms: Plant Proteins/immunology
Antiribosomal P protein antibodies in different populations of patients with systemic lupus erythematosus

Teh LS, Lee MK, Wang F, Manivasagar M, Charles PJ, Nicholson GD, et al.

Br J Rheumatol, 1993 Aug;32(8):663-5.
PMID: 8348266

We report a significantly increased prevalence of antiribosomal P protein antibodies in Malaysian Chinese patients (38%) with SLE compared to white Caucasian (13%) and Afro-Caribbean (20%) patients. The increased prevalence was not due to a generalized increase in autoantibody production because anti-dsDNA and anti-SSA antibodies were present in comparable frequencies in the three ethnic groups while anti-Sm and anti-SSB antibodies were rarely found in the Malaysian Chinese patients.

Matched MeSH terms: Ribosomal Proteins/immunology*
An extensive study of human IgE cross-reactivity of Blo t 5 and Der p 5

Kuo IC, Cheong N, Trakultivakorn M, Lee BW, Chua KY

J Allergy Clin Immunol, 2003 Mar;111(3):603-9.
PMID: 12642844

BACKGROUND: Dual sensitization by Blomia tropicalis and Dermatophagoides pteronyssinus mites is common in tropical and subtropical countries. The human IgE cross-reactivity between clinical important group 5 allergens, Blo t 5 and Der p 5, remains controversial.
OBJECTIVE: This study was undertaken to assess the levels of the IgE cross-reactivity between Blo t 5 and Der p 5 by using sera from a large cohort of asthmatic children in subtropical and tropical countries.
METHODS: Purified recombinant Blo t 5 and Der p 5 were produced in Pichia pastoris and tested against sera from 195 asthmatic children. The IgE cross-reactivity was examined by direct, inhibitory and competitive human IgE enzyme-linked immunosorbent assay as well as skin prick tests.
RESULTS: The Blo t 5 IgE responses were 91.8% (134 of 146) and 73.5% (36 of 49) for Taiwanese and Malaysian sera, respectively. The Blo t 5 specific IgE titers were significantly higher than those of Der p 5 (P

Matched MeSH terms: Recombinant Proteins/immunology
The rubber elongation factor of rubber trees (Hevea brasiliensis) is the major allergen in latex

Czuppon AB, Chen Z, Rennert S, Engelke T, Meyer HE, Heber M, et al.

J Allergy Clin Immunol, 1993 Nov;92(5):690-7.
PMID: 8227860

BACKGROUND: Allergy to latex-containing articles is becoming more and more important because it can result in unexpected life-threatening anaphylactic reactions in sensitized individuals.
METHODS: A protein of 58 kd with an isoelectric point of 8.45 was purified from raw latex and from latex gloves and identified as the major allergen, completely blocking specific IgE antibodies in the serum of latex-sensitized subjects. The allergen is a noncovalent homotetramer molecule, in which the 14.6 kd monomer was identified, by amino acid composition and sequence homologies of tryptic peptides, to be the rubber elongation factor found in natural latex of the Malaysian rubber tree.
RESULTS: Competitive immunoinhibition tests showed that the starch powder covering the finished gloves is the airborne carrier of the allergen, resulting in bronchial asthma on inhalation. The purified allergen can induce allergic reactions in the nanogram range.
CONCLUSION: The identification of the allergen (Hev b I) may help to eliminate it during the production of latex-based articles in the future.

Matched MeSH terms: Proteins/immunology*
TCR-like domain antibody against Mycobacterium tuberculosis (Mtb) heat shock protein antigen presented by HLA-A*11 and HLA-A*24

Dass SA, Norazmi MN, Acosta A, Sarmiento ME, Tye GJ

Int J Biol Macromol, 2020 Jul 15;155:305-314.
PMID: 32240734 DOI: 10.1016/j.ijbiomac.2020.03.229

T cell receptor (TCR)-like antibodies, obtained with the use of phage display technology, sandwich the best of the both arms of the adaptive immune system. In this study, in vitro selections against the latency associated Mycobacterium tuberculosis (Mtb) heat shock protein 16 kDa antigen (16 kDa) presented by HLA-A*011 and HLA-A*24 were carried out with the use of a human domain phage antibody library. TCR-like domain antibodies (A11Ab and A24Ab) were successfully generated recognizing 16 kDa epitopes presented by HLA-A*011 and HLA-A*24 molecules respectively. Both antibodies were found to be functional in soluble form and exhibited strong binding capacity against its targets. The results obtained support the future evaluation of these ligands for the development of diagnostic and therapeutic tools for tuberculosis infection.

Matched MeSH terms: Heat-Shock Proteins/immunology*
Potential application of Leishmania tarentolae as an alternative platform for antibody expression

Lai JY, Klatt S, Lim TS

Crit Rev Biotechnol, 2019 May;39(3):380-394.
PMID: 30720351 DOI: 10.1080/07388551.2019.1566206

Through the discovery of monoclonal antibody (mAb) technology, profound successes in medical treatment against a wide range of diseases have been achieved. This has led antibodies to emerge as a new class of biodrugs. As the "rising star" in the pharmaceutical market, extensive research and development in antibody production has been carried out in various expression systems including bacteria, insects, plants, yeasts, and mammalian cell lines. The major benefit of eukaryotic expression systems is the ability to carry out posttranslational modifications of the antibody. Glycosylation of therapeutic antibodies is one of these important modifications, due to its influence on antibody structure, stability, serum half-life, and complement recruitment. In recent years, the protozoan parasite Leishmania tarentolae has been introduced as a new eukaryotic expression system. L. tarentolae is rich in glycoproteins with oligosaccharide structures that are very similar to humans. Therefore, it is touted as a potential alternative to mammalian expression systems for therapeutic antibody production. Here, we present a comparative review on the features of the L. tarentolae expression system with other expression platforms such as bacteria, insect cells, yeasts, transgenic plants, and mammalian cells with a focus on mAb production.

Matched MeSH terms: Recombinant Proteins/immunology
Innate immune function of serine/threonine-protein kinase from Macrobrachium rosenbergii in response to host-pathogen interactions

Ravichandran G, Pasupuleti M, Arasu MV, Al-Dhabi NA, Arshad A, Arockiaraj J

Fish Shellfish Immunol, 2020 Nov;106:332-340.
PMID: 32758637 DOI: 10.1016/j.fsi.2020.07.068

The occurrences of multiple drug-resistant strains have been relentlessly increasing in recent years. The aquaculture industry has encountered major disease outbreaks and crucially affected by this situation. The usage of non-specific chemicals and antibiotics expedites the stimulation of resistant strains. Triggering the natural defense mechanism would provide an effective and safest way of protecting the host system. Hence, we have investigated the innate immune function of serine/threonine-protein kinase (STPK) in Macrobrachium rosenbergii (Mr). The in-silico protein analysis resulted in the identification of cationic antimicrobial peptide, MrSL-19, with interesting properties from STPK of M. rosenbergii. Antimicrobial assay, FACS and SEM analysis demonstrated that the peptide potentially inhibits Staphylococcus aureus by interacting with its membrane. The toxic study on MrSL-19 demonstrated that the peptide is not toxic against HEK293 cells as well as human erythrocytes. This investigation showed the significant innate immune property of an efficient cationic antimicrobial peptide, MrSL-19 of STPK from M. rosenbergii.

Matched MeSH terms: Arthropod Proteins/immunology
The Potential Use of Anticancer Peptides (ACPs) in the Treatment of Hepatocellular Carcinoma

Ng CX, Lee SH

Curr Cancer Drug Targets, 2020;20(3):187-196.
PMID: 31713495 DOI: 10.2174/1568009619666191111141032

Peptides have acquired increasing interest as promising therapeutics, particularly as anticancer alternatives during recent years. They have been reported to demonstrate incredible anticancer potentials due to their low manufacturing cost, ease of synthesis and great specificity and selectivity. Hepatocellular carcinoma (HCC) is among the leading cause of cancer death globally, and the effectiveness of current liver treatment has turned out to be a critical issue in treating the disease efficiently. Hence, new interventions are being explored for the treatment of hepatocellular carcinoma. Anticancer peptides (ACPs) were first identified as part of the innate immune system of living organisms, demonstrating promising activity against infectious diseases. Differentiated beyond the traditional effort on endogenous human peptides, the discovery of peptide drugs has evolved to rely more on isolation from other natural sources or through the medicinal chemistry approach. Up to the present time, the pharmaceutical industry intends to conduct more clinical trials for the development of peptides as alternative therapy since peptides possess numerous advantages such as high selectivity and efficacy against cancers over normal tissues, as well as a broad spectrum of anticancer activity. In this review, we present an overview of the literature concerning peptide's physicochemical properties and describe the contemporary status of several anticancer peptides currently engaged in clinical trials for the treatment of hepatocellular carcinoma.

Matched MeSH terms: Neoplasm Proteins/immunology

Filters

Please provide feedback to Administrator ([email protected])

External Links