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Displaying publications 41 - 50 of 50 in total

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Mycobacterial antibody levels and immune restoration disease in HIV patients treated in South East Asia

Sumatoh HR, Oliver BG, Kumar M, Elliott JH, Vonthanak S, Vun MC, et al.

Biomark Med, 2011 Dec;5(6):847-53.
PMID: 22103621 DOI: 10.2217/bmm.11.79

Immune restoration disease (IRD) associated with Mycobacterium tuberculosis parallels the reconstitution of a pathogen-specific Th1 response. However, it is not clear whether humoral responses to M. tuberculosis antigens also rise, or whether antibody levels predict IRD. Here, humoral immunity to M. tuberculosis antigens was investigated in four Asian cohorts.

Matched MeSH terms: Immunoglobulin G/immunology
In vitro and in vivo characterization of chimeric duck Tembusu virus based on Japanese encephalitis live vaccine strain SA14-14-2

Wang HJ, Liu L, Li XF, Ye Q, Deng YQ, Qin ED, et al.

J Gen Virol, 2016 07;97(7):1551-1556.
PMID: 27100268 DOI: 10.1099/jgv.0.000486

Duck Tembusu virus (DTMUV), a newly identified flavivirus, has rapidly spread to China, Malaysia and Thailand. The potential threats to public health have been well-highlighted; however its virulence and pathogenesis remain largely unknown. Here, by using reverse genetics, a recombinant chimeric DTMUV based on Japanese encephalitis live vaccine strain SA14-14-2 was obtained by substituting the corresponding prM and E genes (named ChinDTMUV). In vitro characterization demonstrated that ChinDTMUV replicated efficiently in mammalian cells with small-plaque phenotype in comparison with its parental viruses. Mouse tests showed ChinDTMUV exhibited avirulent phenotype in terms of neuroinvasiveness, while it retained neurovirulence from its parental virus DTMUV. Furthermore, immunization with ChinDTMUV was evidenced to elicit robust IgG and neutralizing antibody responses in mice. Overall, we successfully developed a viable chimeric DTMUV, and these results provide a useful platform for further investigation of the pathogenesis of DTMUV and development of a live attenuated DTMUV vaccine candidate.

Matched MeSH terms: Immunoglobulin G/immunology
Longevity of antibody responses to a Salmonella typhi-specific outer membrane protein: interpretation of a dot enzyme immunosorbent assay in an area of high typhoid fever endemicity

Choo KE, Davis TM, Ismail A, Ong KH

Am J Trop Med Hyg, 1997 Dec;57(6):656-9.
PMID: 9430522

The objective of this study was to investigate the longevity of positive dot enzyme immunosorbent assay (dot EIA) results for IgM and IgG to a Salmonella typhi outer membrane protein in Malaysian children with enteric fever. The patients were children one month to 12 years of age with clinical evidence of typhoid fever, positive blood or stool cultures for S. typhi, and/or a positive Widal test result who were admitted over a two-year period to General Hospital (Kota Bharu, Malaysia). These patients received standard inpatient treatment for enteric fever including chloramphenicol therapy for 14 days. Dot EIA tests were performed as part of clinical and laboratory assessments on admission, at two weeks, and then at 3, 6, 9, 12, 15, 18, and 21 months postdischarge. Assessment of the longevity of positive dot EIA IgM and IgG titers was done by Kaplan-Meier analysis. In 94 evaluable patients, 28% were dot EIA IgM positive but IgG negative on admission, 50% were both IgM and IgG positive, and 22% were IgM negative and IgG positive. Mean persistence of IgM dot EIA positivity was 2.6 months (95% confidence interval = 2.0-3.1 months) and that of IgG was 5.4 months (4.5-6.3 months). There were no significant differences between the three subgroups. Thus, positive IgM and IgG results determined by dot EIA within four and seven months, respectively, following documented or suspected enteric fever in a child from an endemic area should be interpreted with caution. In other clinical situations, the dot EIA remains a rapid and reliable aid to diagnosis.

Matched MeSH terms: Immunoglobulin G/immunology
Expression of a codon-optimised recombinant Ara h 2.02 peanut allergen in Escherichia coli

Lew MH, Lim RL

Appl Microbiol Biotechnol, 2016 Jan;100(2):661-71.
PMID: 26411458 DOI: 10.1007/s00253-015-6953-y

Current diagnostic tools for peanut allergy using crude peanut extract showed low predictive value and reduced specificity for detection of peanut allergen-specific immunoglobulin E (IgE). The Ara h 2.02, an isoform of the major peanut allergen Ara h 2, contains three IgE epitope recognition sequence of 'DPYSPS' and may be a better reagent for component resolve diagnosis. This research aimed to generate a codon-optimised Ara h 2.02 gene for heterologous expression in Escherichia coli and allergenicity study of this recombinant protein. The codon-optimised gene was generated by PCR using overlapping primers and cloned into the pET-28a (+) expression vector. Moderate expression of a 22.5 kDa 6xhistidine-tagged recombinant Ara h 2.02 protein (6xHis-rAra h 2.02) in BL21 (DE3) host cells was observed upon induction with 1 mM isopropyl β-D-1-thiogalactopyranoside (IPTG). The insoluble recombinant protein was purified under denaturing condition using nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography and refolded by dialysis in decreasing urea concentration, amounting to a yield of 74 mg/l of expression culture. Matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) and immunoblot analysis confirmed the production of the recombinant 6xHis-rAra h 2.02. The refolded recombinant 6xHis-rAra h 2.02, with or without adjuvant, was able to elicit comparable level of allergen-specific IgE and IgG1 in sensitised Balb/c mice. In addition, the specific IgE antibodies raised against the recombinant protein were able to recognise the native Ara h 2 protein, demonstrating its allergenicity and potential as a reagent for diagnosis and therapeutic study.

Matched MeSH terms: Immunoglobulin G/immunology
Fulltext Immunogenicity of recombinant Mycobacterium bovis bacille Calmette-Guèrin clones expressing T and B cell epitopes of Mycobacterium tuberculosis antigens

Mohamud R, Azlan M, Yero D, Alvarez N, Sarmiento ME, Acosta A, et al.

BMC Immunol, 2013;14 Suppl 1:S5.
PMID: 23458635 DOI: 10.1186/1471-2172-14-S1-S5

Recombinant Mycobacterium bovis bacille Calmette-Guèrin (rBCG) expressing three T cell epitopes of Mycobacterium tuberculosis (MTB) Ag85B antigen (P1, P2, P3) fused to the Mtb8.4 protein (rBCG018) or a combination of these antigens fused to B cell epitopes from ESAT-6, CFP-10 and MTP40 proteins (rBCG032) were used to immunize Balb/c mice. Total IgG responses were determined against Mtb8.4 antigen and ESAT-6 and CFP-10 B cell epitopes after immunization with rBCG032. Mice immunized with rBCG032 showed a significant increase in IgG1 and IgG2a antibodies against ESAT-6 and MTP40 (P1) B cell epitopes and IgG3 against both P1 and P2 B cell epitopes of MPT40. Splenocytes from mice immunized with rBCG018 proliferated against Ag85B P2 and P3 T cell epitopes and Mtb8.4 protein whereas those from mice-immunized with rBCG032 responded against all Ag85B epitopes and the ESAT-6 B cell epitope. CD4⁺ and CD8⁺ lymphocytes from mice immunized with rBCG018 produced primarily Th1 type cytokines in response to the T cell epitopes. Similar pattern of recognition against the T cell epitopes were obtained with rBCG032 with the additional recognition of ESAT-6, CFP-10 and one of the MTP40 B cell epitopes with the same pattern of cytokines. This study demonstrates that rBCG constructs expressing either T or T and B cell epitopes of MTB induced appropriate immunogenicity against MTB.

Matched MeSH terms: Immunoglobulin G/immunology
An orally active geranyl acetophenone attenuates airway remodeling in a murine model of chronic asthma

Lee YZ, Shaari K, Cheema MS, Tham CL, Sulaiman MR, Israf DA

Eur J Pharmacol, 2017 Feb 15;797:53-64.
PMID: 28089919 DOI: 10.1016/j.ejphar.2017.01.011

2,4,6-Trihydroxy-3-geranyl acetophenone (tHGA) is a synthetic compound that is naturally found in Melicope ptelefolia. We had previously demonstrated that parenteral administration of tHGA reduces pulmonary inflammation in OVA-sensitized mice. In this study, we evaluated the effect of orally administered tHGA upon airway remodeling in a murine model of chronic asthma. Female BALB/C mice were sensitized intraperitoneally with ovalbumin (OVA) on day 0, 7 and 14, followed by aerosolized 1% OVA 3 times per week for 6 weeks. Control groups were sensitized with saline. OVA sensitized animals were either treated orally with vehicle (saline with 1% DMSO and Tween 80), tHGA (80, 40, 20mg/kg) or zileuton (30mg/kg) 1h prior to each aerosolized OVA sensitization. On day 61, mice underwent methacholine challenge to determine airway hyperresponsiveness prior to collection of bronchoalveolar lavage (BAL) fluid and lung samples. BAL fluid inflammatory cell counts and cytokine concentrations were evaluated while histological analysis and extracellular matrix protein concentrations were determined on collected lung samples. Oral tHGA treatment attenuated airway hyperresponsiveness and inhibited airway remodeling in a dose-dependent fashion. tHGA's effect on airway remodeling could be attributed to the reduction of inflammatory cell infiltration and decreased expression of cytokines associated with airway remodeling. Oral administration of tHGA attenuates airway hyperresponsiveness and remodeling in OVA-induced BALB/c mice. tHGA is an interesting compound that should be evaluated further for its possible role as an alternative non-steroidal pharmacological approach in the management of asthma.

Matched MeSH terms: Immunoglobulin G/immunology
IgG4-related disease: features and treatment response in a multi-ethnic cohort in Singapore

Fong W, Liew I, Tan D, Lim KH, Low A, Leung YY

Clin Exp Rheumatol, 2018 05 24;36 Suppl 112(3):89-93.
PMID: 29846168

OBJECTIVES: To describe the features and treatment outcomes of IgG4-RD in multi-ethnic patients in Singapore.
METHODS: Retrospective study was performed on IgG4-RD patients identified from patient databases in a tertiary hospital.
RESULTS: Fourty-two patients (76% male) were included; 79% fulfilled the 2011 comprehensive diagnostic criteria for IgG4-RD for definite IgG4-RD. 81% were Chinese and 19% were Malays. Common initial manifestations included jaundice (52%), abdominal pain (36%) and swollen salivary glands (26%). Only 36% had a history of allergy. 83% had ≥ 1 organ involvement. Erythrocyte sedimentation rate, immunoglobulin E, IgG2 and IgG4 levels were elevated in 84%, 100%, 70% and 44% of patients, respectively. The most common histopathological feature was >10 IgG4+ cells per high power field (66%). 94% (34/36) of patients were treated with moderate to high doses of glucocorticoids, including 17 patients with combination immunosuppressants. Of these, all patients responded to therapy by 3 months. With a median (range) follow-up of 4.1 (0.4-13.8) years, 69% (25/36) needed low dose of glucocorticoids to maintain disease remission. Twenty-six per cent had relapse of disease, of which 82% had disease recurrence in the same organs.
CONCLUSIONS: Pancreatitis, lymphoadenopathy and cholangitis were the commonest manifestations in Asians with IgG4-RD. All patients responded to glucocorticoid therapy by 3 months, two-thirds required maintenance therapy with glucocorticoids, and one-quarter developed relapse of disease.

Matched MeSH terms: Immunoglobulin G/immunology*
Fulltext Changes in the amino acid sequence of the recombinant human factor VIIa analog, vatreptacog alfa, are associated with clinical immunogenicity

Mahlangu JN, Weldingh KN, Lentz SR, Kaicker S, Karim FA, Matsushita T, et al.

J Thromb Haemost, 2015 Nov;13(11):1989-98.
PMID: 26362483 DOI: 10.1111/jth.13141

BACKGROUND: Vatreptacog alfa, a recombinant human factor VIIa (rFVIIa) analog developed to improve the treatment of bleeds in hemophilia patients with inhibitors, differs from native FVIIa by three amino acid substitutions. In a randomized, double-blind, crossover, confirmatory phase III trial (adept(™) 2), 8/72 (11%) hemophilia A or B patients with inhibitors treated for acute bleeds developed anti-drug antibodies (ADAs) to vatreptacog alfa.
OBJECTIVES: To characterize the formation of anti-vatreptacog alfa ADAs in hemophilia patients with inhibitors.
METHODS/PATIENTS: This was a post hoc analysis of adept(™) 2. Immunoglobulin isotype determination, specificity analysis of rFVIIa cross-reactive antibodies, epitope mapping of rFVIIa single mutant analogs and pharmacokinetic (PK) profiling were performed to characterize the ADAs.
RESULTS: Immunoglobulin isotyping indicated that the ADAs were of the immunoglobulin G subtype. In epitope mapping, none of the rFVIIa single mutant analogs (V158D, E296V or M298Q) contained the complete antibody epitope, confirming that the antibodies were specific for vatreptacog alfa. In two patients, for whom PK profiling was performed both before and after the development of ADAs, vatreptacog alfa showed a prolonged elimination phase following ADA development. During the follow-up evaluation, the rFVIIa cross-reactivity disappeared after the last vatreptacog alfa exposure, despite continued exposure to rFVIIa as part of standard care.
CONCLUSIONS: Results from the vatreptacog alfa phase III trial demonstrate that the specific changes made, albeit relatively small, to the FVIIa molecule alter its clinical immunogenicity.

Matched MeSH terms: Immunoglobulin G/immunology
Fulltext Immune response in acute Toxoplasma infection of Balb/C, ICR and CBA/J mice

Suresh K, Mak JW, Yong HS

Southeast Asian J Trop Med Public Health, 1991 Sep;22(3):452-4.
PMID: 1818401
Matched MeSH terms: Immunoglobulin G/immunology
Antigenic proteins of Helicobacter pylori of potential diagnostic value

Khalilpour A, Santhanam A, Wei LC, Saadatnia G, Velusamy N, Osman S, et al.

Asian Pac J Cancer Prev, 2013;14(3):1635-42.
PMID: 23679248

Helicobacter pylori antigen was prepared from an isolate from a patient with a duodenal ulcer. Serum samples were obtained from culture-positive H. pylori infected patients with duodenal ulcers, gastric ulcers and gastritis (n=30). As controls, three kinds of sera without detectable H. pylori IgG antibodies were used: 30 from healthy individuals without history of gastric disorders, 30 from patients who were seen in the endoscopy clinic but were H. pylori culture negative and 30 from people with other diseases. OFF-GEL electrophoresis, SDS-PAGE and Western blots of individual serum samples were used to identify protein bands with good sensitivity and specificity when probed with the above sera and HRP-conjugated anti-human IgG. Four H. pylori protein bands showed good (≥ 70%) sensitivity and high specificity (98-100%) towards anti-Helicobacter IgG antibody in culture- positive patients sera and control sera, respectively. The identities of the antigenic proteins were elucidated by mass spectrometry. The relative molecular weights and the identities of the proteins, based on MALDI TOF/ TOF, were as follows: CagI (25 kDa), urease G accessory protein (25 kDa), UreB (63 kDa) and proline/pyrroline- 5-carboxylate dehydrogenase (118 KDa). These identified proteins, singly and/or in combinations, may be useful for diagnosis of H. pylori infection in patients.

Matched MeSH terms: Immunoglobulin G/immunology