scholarly journals Plasmodium falciparum serology: A comparison of two protein production methods for analysis of antibody responses by protein microarray

2020 ◽  
Author(s):  
Tate Oulton ◽  
Joshua Obiero ◽  
Isabel Rodriguez ◽  
Isaac Ssewanyana ◽  
Rebecca A Dabbs ◽  
...  

The evaluation of protein antigens as putative serologic biomarkers of infection has increasingly shifted to high-throughput, multiplex approaches such as the protein microarray. In vitro Transcription/Translation (IVTT) systems (a similarly high-throughput protein expression method) are already widely utilised in the production of protein microarrays, though purified recombinant proteins derived from more traditional whole cell based expression systems also play an important role in biomarker characterisation. Here we have performed a side-by-side comparison of antigen-matched protein targets from an IVTT and purified recombinant system, on a protein microarray. The magnitude and range of antibody responses to purified recombinants was found to be greater than that of IVTT proteins, and responses between targets from opposing expression systems did not clearly correlate. However, responses between amino acid sequence-matched targets from each expression system were more closely correlated. Despite the lack of a clearly defined relationship between antigen-matched targets produced in each expression system, our data indicate that protein microarrays produced using either method can be used confidently, in a context dependent manner, though care should be taken when comparing data derived from contrasting approaches.

2004 ◽  
Vol 9 (8) ◽  
pp. 687-694 ◽  
Author(s):  
Yoonsuk Lee ◽  
Dong-Ku Kang ◽  
Soo-Ik Chang ◽  
Moon Hi Han ◽  
In-Cheol Kang

Protein microarray is an emerging technology that makes high-throughput analysis possible for protein-protein interactions and analysis of proteome and biomarkers in parallel. The authors investigated the application of a novel protein microarray chip, Proteo Chip, in new drug discovery. Integrin αvβ3 microarray immobilized on the Proteo Chip was employed to screen new active peptides against the integrin from multiple hexapeptide sublibraries of a positional scanning synthetic peptide combinatorial library (PS-SPCL). The integrin αvβ3-vitronectin interaction was successfully demonstrated on the integrin microarray in a dose-dependent manner andwas inhibited not only by the syntheticRGDpeptide but also by various integrin antagonists on the integrin microarray chip. Novel peptide ligands with high affinity to the integrin were also identified from the peptide libraries with this chip-based screening system by a competitive inhibition assay in a simultaneous and highthroughput fashion. The authors have confirmed antiangiogenic functions of the novel peptides thus screened through an in vitro and in vivo angiogenesis assay. These results provide evidence that the Proteo Chip is a promising tool for highthroughput screening of lead molecules in new drug development.


2021 ◽  
Author(s):  
Alexander J Speakman ◽  
Katherine E Dunn

Fluorescent RNA aptamers are an increasingly used tool for quantifying transcription and for visualising RNA interactions, both in vitro and in vivo. However when tested in the commercially available, E. coli extract based Expressway™ cell-free expression system, no fluorescence is detected. The same experimental setup is shown to successfully produce fluorescent RNA aptamers when tested in another buffer designed for in vitro transcription, and RNA purification of the Expressway™ reaction products show that transcription does occur, but does not result in a fluorescent product. In this paper we demonstrate the incompatibility of a narrow selection of RNA aptamers in one particular cell-free expression system, and consider that similar issues may arise with other cell-free expression systems, RNA aptamers, and their corresponding fluorophores.


2022 ◽  
Vol 12 ◽  
Author(s):  
Hongqiang Lou ◽  
Xusheng Li ◽  
Xiusheng Sheng ◽  
Shuiqin Fang ◽  
Shaoye Wan ◽  
...  

Campylobacter jejuni (C. jejuni) is one of the major pathogens contributing to the enteritis in humans. Infection can lead to numerous complications, including but not limited to Guillain-Barre syndrome, reactive arthritis, and Reiter’s syndrome. Over the past two decades, joint efforts have been made toward developing a proper strategy of limiting the transmission of C. jejuni to humans. Nevertheless, except for biosecurity measures, no available vaccine has been developed so far. Judging from the research findings, Omp18, AhpC outer membrane protein, and FlgH flagellin subunits of C. jejuni could be adopted as surface protein antigens of C. jejuni for screening dominant epitope thanks to their strong antigenicity, expression of varying strains, and conservative sequence. In this study, bioinformatics technology was adopted to analyze the T-B antigenic epitopes of Omp18, AhpC, and FlgH in C. jejuni strain NCTC11168. Both ELISA and Western Blot methods were adopted to screen the dominant T-B combined epitope. GGS (GGCGGTAGC) sequence was adopted to connect the dominant T-B combined epitope peptides and to construct the prokaryotic expression system of tandem repeats of antigenic epitope peptides. The mouse infection model was adopted to assess the immunoprotective effect imposed by the trivalent T-B combined with antigen epitope peptide based on Omp18/AhpC/FlgH. In this study, a tandem epitope AhpC-2/Omp18-1/FlgH-1 was developed, which was composed of three epitopes and could effectively enhance the stability and antigenicity of the epitope while preserving its structure. The immunization of BALB/c mice with a tandem epitope could induce protective immunity accompanied by the generation of IgG2a antibody response through the in vitro synthesis of IFN-γ cytokines. Judging from the results of immune protection experiments, the colonization of C. jejuni declined to a significant extent, and it was expected that AhpC-2/Omp18-1/FlgH-1 could be adopted as a candidate antigen for genetic engineering vaccine of C. jejuni MAP.


The Analyst ◽  
2014 ◽  
Vol 139 (6) ◽  
pp. 1303-1326 ◽  
Author(s):  
Valentin Romanov ◽  
S. Nikki Davidoff ◽  
Adam R. Miles ◽  
David W. Grainger ◽  
Bruce K. Gale ◽  
...  

Of the diverse analytical tools used in proteomics, protein microarrays possess the greatest potential for providing fundamental information on protein, ligand, analyte, receptor, and antibody affinity-based interactions, binding partners and high-throughput analysis.


npj Vaccines ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Daniel Tapia ◽  
Javier I. Sanchez-Villamil ◽  
Alfredo G. Torres

Abstract Burkholderia mallei (Bm) is a facultative intracellular pathogen and the etiological agent of glanders, a highly infectious zoonotic disease occurring in equines and humans. The intrinsic resistance to antibiotics, lack of specific therapy, high mortality, and history as a biothreat agent, prompt the need of a safe and effective vaccine. However, the limited knowledge of protective Bm-specific antigens has hampered the development of a vaccine. Further, the use of antigen-delivery systems that enhance antigen immunogenicity and elicit robust antigen-specific immune responses has been limited and could improve vaccines against Bm. Nanovaccines, in particular gold nanoparticles (AuNPs), have been investigated as a strategy to broaden the repertoire of vaccine-mediated immunity and as a tool to produce multivalent vaccines. To synthesize a nano-glycoconjugate vaccine, six predicted highly immunogenic antigens identified by a genome-wide bio- and immuno-informatic analysis were purified and coupled to AuNPs along with lipopolysaccharide (LPS) from B. thailandensis. Mice immunized intranasally with individual AuNP-protein-LPS conjugates, showed variable degrees of protection against intranasal Bm infection, while an optimized combination formulation (containing protein antigens OmpW, OpcP, and Hemagglutinin, along with LPS) showed complete protection against lethality in a mouse model of inhalational glanders. Animals immunized with different nano-glycoconjugates showed robust antigen-specific antibody responses. Moreover, serum from animals immunized with the optimized nano-glycoconjugate formulation showed sustained antibody responses with increased serum-mediated inhibition of adherence and opsonophagocytic activity in vitro. This study provides the basis for the rational design and construction of a multicomponent vaccine platform against Bm.


2008 ◽  
Vol 13 (5) ◽  
pp. 415-423 ◽  
Author(s):  
Klaas J. Wierenga ◽  
Kent Lai ◽  
Peter Buchwald ◽  
Manshu Tang

Inherited deficiency of galactose-1-phosphate uridyltransferase (GALT) can result in a potentially lethal disorder called classic galactosemia. Although the neonatal lethality associated with this disease can be prevented through early diagnosis and a galactose-restricted diet, the lack of effective therapy continues to have consequences: developmental delay, neurological disorders, and premature ovarian failure are common sequelae in childhood and adulthood. Several lines of evidence indicate that an elevated level of galactose-1-phosphate (gal-1-p), the product of galactokinase (GALK), is a major, if not sole, pathogenic mechanism in patients with classic galactosemia. The authors hypothesize that elimination of gal-1-p production by inhibiting GALK will relieve GALT-deficient cells from galactose toxicity. To test this hypothesis, they obtained human GALK using a bacterial expression system. They developed a robust, miniaturized, high-throughput GALK assay (Z′ factor = 0.91) and used this assay to screen against libraries composed of 50,000 chemical compounds with diverse structural scaffolds. They selected 150 compounds that, at an average concentration of 33.3 µM, inhibited GALK activity in vitro more than 86.5% and with a reproducibility score of at least 0.7 for a confirmatory screen under identical experimental conditions. Of these 150 compounds, 34 were chosen for further characterization. Preliminary results indicated that these 34 compounds have potential to serve as leads to the development of more effective therapy of classic galactosemia. ( Journal of Biomolecular Screening 2008:415-423)


1992 ◽  
Vol 175 (1) ◽  
pp. 211-216 ◽  
Author(s):  
T G Yin ◽  
P Schendel ◽  
Y C Yang

The availability of large quantities of highly purified recombinant interleukin 11 (rhuIL-11) has allowed us to investigate the effects of rhuIL-11 on sheep red blood cell (SRBC)-specific antibody responses in the murine system. The results showed that rhuIL-11 was effective in enhancing the generation of mouse spleen SRBC-specific plaque-forming cells (PFC) in the in vitro cell culture system in a dose-dependent manner. These effects of rhuIL-11 were abrogated completely by the addition of anti-rhuIL-11 antibody, but not by the addition of preimmunized rabbit serum. Cell-depletion studies revealed that L3T4 (CD4)+ T cells, but not Lyt-2 (CD8)+ T cells, are required in the rhuIL-11-stimulated augmentation of SRBC-specific antibody responses. The effects of rhuIL-11 on the SRBC-specific antibody responses in vivo were also examined. RhuIL-11 administration to normal C3H/HeJ mice resulted in a dose-dependent increase in the number of spleen SRBC-specific PFC as well as serum SRBC-specific antibody titer in both the primary and secondary immune responses. In mice immunosuppressed by cyclophosphamide treatment, rhuIL-11 administration significantly augmented the number of spleen SRBC-specific PFC as well as serum SRBC-specific antibody titer when compared with the cyclophosphamide-treated mice without IL-11 treatment. These results demonstrated that IL-11 is a novel cytokine involved in modulating antigen-specific antibody responses in vitro as well as in vivo.


1995 ◽  
Vol 15 (11) ◽  
pp. 6206-6212 ◽  
Author(s):  
C Reinbothe ◽  
K Apel ◽  
S Reinbothe

The NADPH:protochlorophyllide oxidoreductase precursor protein (pPorA) of barley (Hordeum vulgare L. cv. Carina), synthesized from a full-length cDNA clone by coupling in vitro transcription and translation, is a catalytically active protein. It converts protochlorophyllide to chlorophyllide in a light- and NADPH-dependent manner. At least the pigment product of catalysis remains tightly bound to the precursor protein. The chlorophyllide-pPorA complex differs markedly from the protochlorophyllide-pPorA complex with respect to sensitivity to attack by a light-induced, nucleus-encoded, and energy-dependent protease activity of barley plastids. The pPorA-chlorophyllide complex is rapidly degraded, in contrast to pPorA-protochlorophyllide complexes containing or lacking NADPH, which are both resistant to protease treatment. Unexpectedly, pPorA devoid of its substrates or products was less sensitive to proteolysis than the pPorA-chlorophyllide complex, suggesting that both substrate binding and product formation during catalysis had caused differential changes in protein conformation.


1988 ◽  
Vol 8 (10) ◽  
pp. 4502-4509 ◽  
Author(s):  
T W Christianson ◽  
D A Clayton

Vertebrate mitochondrial genomes contain a putative transcription termination site at the boundary between the genes for 16S rRNA and leucyl-tRNA. We have described previously an in vitro transcription system from human cells with the capacity to generate RNA 3' ends with the same map positions as those synthesized in vivo. By assaying the ability of variously truncated templates to support 3'-end formation, we demonstrated that the tridecamer sequence 5'-TGGCAGAGCCCCGG-3', contained entirely within the gene for leucyl-tRNA, is necessary to direct accurate termination. When two tridecamer sequences and their immediate flanking regions were placed in tandem, termination occurred at both promoter-proximal and promoter-distal sites. Furthermore, termination was competitively inhibited, in a concentration-dependent manner, by DNA containing the tridecamer sequence. These results suggest a modest sequence requirement for transcription termination that is contingent on a factor capable of recognizing the presence of the tridecamer DNA sequence.


2021 ◽  
Author(s):  
Chen Liu

Transglutaminases (TGs) are a family of crosslinking enzymes catalyzing the formation of intra- and inter-molecular glutamine-lysine isopeptide bonds in a calcium dependent manner. Activation of transglutaminases is pathogenically associated with severe human diseases including neurodegenerations, cardiovascular diseases, and autoimmune diseases. Although continuous efforts determining the enzymes substrate preference have been witnessed, a high-throughput assay platform with the omic efficiency is still missing for the global identification of substrate-specific TG modification sites. In this study we report a protein microarray-based in vitro TG assay platform for rapid and large-scale (up to 30000 reactions per chip) determination of the glutamine (Q)-bearing TG modification motifs. With this platform we identified the Q16 in superoxide dismutase 1 and Q109 in alpha-synuclein as the modification sites for tissue transglutaminase (TG2), the most ubiquitous member of the enzyme family. Of particular interest, we found a close match between the modification motif and published vaccine epitope sequence in alpha-synuclein. Our data collectively suggest the glutamine and its follow-up five residues on the C terminal compose a minimal determinant motif for TG2 modification. To screen for site-specific interfering peptides and assist gene editing-based protein engineering, we developed an onchip amino-acid scanning method for the optimization of TG2 modification motifs. Using this approach we optimized the TG2 modification motif QQIV in the extracellular matrix protein fibronectin and obtained 14 variants with significantly higher TG2 reactivity that might serve as the competitive inhibitor peptides and 1 with lower reactivity. We further confirmed the efficacy of this approach using 12-mer peptides, the longest ones that could be synthesized on the chip. Taken together, our synthetic assay platform will be able to not only deliver a precise epitope blueprint for personalized immunotherapy and vaccination but also provide proof-of-concept and directional studies for TG-based peptide discovery and protein design.


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