MyMedR

Displaying publications 61 - 64 of 64 in total

Abstract:

Sort:

Immunogenic properties of recombinant ectodomain of Newcastle disease virus hemagglutinin-neuraminidase protein expressed in Escherichia coli

Wong SK, Tan WS, Omar AR, Tan CS, Yusoff K

Acta Virol., 2009;53(1):35-41.
PMID: 19301949

Hemagglutinin-neuraminidase (HN) protein of Newcastle disease virus (NDV) plays a vital role in the viral infectivity, host immunity, and disease diagnosis. A portion of the HN gene encoding the ectodomain (nt 142-1739) was cloned and expressed in Escherichia coli yielding an insoluble HN protein and a soluble NusA-HN protein containing N-utilization substance A (NusA) fusion component. Both recombinant proteins were purified and used for immunization of chickens. The recombinant HN protein induced higher antibody titers as compared to the recombinant NusA-HN protein. These antibodies were able to react in immunoblot analysis with the corresponding recombinant proteins as well as with the HN protein of NDV.

Matched MeSH terms: Recombinant Proteins/immunology
Solubility, immunogenicity and physical properties of the nucleocapsid protein of Nipah virus produced in Escherichia coli

Tan WS, Ong ST, Eshaghi M, Foo SS, Yusoff K

J Med Virol, 2004 May;73(1):105-12.
PMID: 15042656

The nucleocapsid (N) protein of Nipah virus (NiV) can be produced in three Escherichia coli strains [TOP10, BL21(DE3) and SG935] under the control of trc promoter. However, most of the product existed in the form of insoluble inclusion bodies. There was no improvement in the solubility of the product when this protein was placed under the control of T7 promoter. However, the solubility of the N protein was significantly improved by lowering the growth temperature of E. coli BL21(DE3) cell cultures. Solubility analysis of N- and C-terminally deleted mutants revealed that the full-length N protein has the highest solubility. The soluble N protein could be purified efficiently by sucrose gradient centrifugation and nickel affinity chromatography. Electron microscopic analysis of the purified product revealed that the N protein assembled into herringbone-like particles of different lengths. The C-terminal end of the N protein contains the major antigenic region when probed with antisera from humans and pigs infected naturally.

Matched MeSH terms: Recombinant Proteins/immunology
Characterization of secreted recombinant Toxoplasma gondii surface antigen 2 (SAG2) heterologously expressed by the yeast Pichia pastoris

Fong MY, Lau YL, Zulqarnain M

Biotechnol Lett, 2008 Apr;30(4):611-8.
PMID: 18043869

The surface antigen 2 (SAG2) gene of the protozoan parasite, Toxoplasma gondii, was cloned and extracellularly expressed in the yeast Pichia pastoris. The effectiveness of the secreted recombinant SAG2 (rSAG2-S) as a serodiagnosis reagent was assessed by western blots and ELISA. In the western blot assay, rSAG2-S reacted with all Toxoplasma-antibody positive human serum samples but not with Toxoplasma-negative samples. In the ELISA, rSAG2-S yielded sensitivity rates ranging from 80% (IgG negative, IgM positive) to 100% (IgG positive, IgM negative). In vivo experiments showed that serum from mice immunized with rSAG2-S reacted specifically with the native SAG2 of T. gondii. These mice were protected when challenged with live cells of T. gondii.

Matched MeSH terms: Recombinant Proteins/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: Recombinant Proteins/immunology