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| 2. |
- Gustavsson, Elin, et al.
(author)
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Surrogate antigens as targets for proteome-wide binder selection
- 2011
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In: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 28:4, s. 302-311
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Journal article (peer-reviewed)abstract
- In the last decade, many initiatives have been taken to develop antibodies for proteome-wide studies, as well as characterization and validation of clinically relevant disease biomarkers. Phage display offers many advantages compared to conventional antibody generation by immunization and hybridoma technology, since it is an unlimited resource of affinity reagents without batch-to-batch variation and is amendable for high throughput. One of the major bottlenecks to proteome-wide binder selection is the limited supply of suitable target antigens representative of the human proteome. Here, we provide proof of principle of using easily accessible, cancer-associated protein epitope signature tags (PrESTs), routinely generated within the Human Protein Atlas project, as surrogate antigens in phage selectionsfor the retrieval of target specific binders. These binders were subsequently tested in western blot, immunohistochemistry and protein microarray application to demonstrate their functionality.
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| 3. |
- Lundberg, Emma, et al.
(author)
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Defining the transcriptome and proteome in three functionally different human cell lines
- 2010
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In: Molecular Systems Biology. - : EMBO. - 1744-4292 .- 1744-4292. ; 6, s. 450-
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Journal article (peer-reviewed)abstract
- An essential question in human biology is how cells and tissues differ in gene and protein expression and how these differences delineate specific biological function. Here, we have performed a global analysis of both mRNA and protein levels based on sequence-based transcriptome analysis (RNA-seq), SILAC-based mass spectrometry analysis and antibody-based confocal microscopy. The study was performed in three functionally different human cell lines and based on the global analysis, we estimated the fractions of mRNA and protein that are cell specific or expressed at similar/different levels in the cell lines. A highly ubiquitous RNA expression was found with > 60% of the gene products detected in all cells. The changes of mRNA and protein levels in the cell lines using SILAC and RNA ratios show high correlations, even though the genome-wide dynamic range is substantially higher for the proteins as compared with the transcripts. Large general differences in abundance for proteins from various functional classes are observed and, in general, the cell-type specific proteins are low abundant and highly enriched for cell-surface proteins. Thus, this study shows a path to characterize the transcriptome and proteome in human cells from different origins.
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- Uhlén, Mathias, et al.
(author)
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Antibody-based Protein Profiling of the Human Chromosome 21
- 2012
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In: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 11:3
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Journal article (peer-reviewed)abstract
- The Human Proteome Project has been proposed to create a knowledge-based resource based on a systematical mapping of all human proteins, chromosome by chromosome, in a gene-centric manner. With this background, we here describe the systematic analysis of chromosome 21 using an antibody-based approach for protein profiling using both confocal microscopy and immunohistochemistry, complemented with transcript profiling using next generation sequencing data. We also describe a new approach for protein isoform analysis using a combination of antibody-based probing and isoelectric focusing. The analysis has identified several genes on chromosome 21 with no previous evidence on the protein level, and the isoform analysis indicates that a large fraction of human proteins have multiple isoforms. A chromosome-wide matrix is presented with status for all chromosome 21 genes regarding subcellular localization, tissue distribution, and molecular characterization of the corresponding proteins. The path to generate a chromosome-specific resource, including integrated data from complementary assay platforms, such as mass spectrometry and gene tagging analysis, is discussed.
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- Älgenäs, Cajsa, et al.
(author)
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Antibody performance in western blot applications is context- dependent
- 2014
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In: Biotechnology Journal. - : Wiley. - 1860-6768 .- 1860-7314. ; 9:3, s. 435-445
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Journal article (peer-reviewed)abstract
- An important concern for the use of antibodies in various applications, such as western blot (WB) or immunohistochemistry (IHC), is specificity. This calls for systematic validations using well-designed conditions. Here, we have analyzed 13000 antibodies using western blot with lysates from human cell lines, tissues, and plasma. Standardized stratification showed that 45% of the antibodies yielded supportive staining, and the rest either no staining (12%) or protein bands of wrong size (43%). A comparative study of WB and IHC showed that the performance of antibodies is application-specific, although a correlation between no WB staining and weak IHC staining could be seen. To investigate the influence of protein abundance on the apparent specificity of the antibody, new WB analyses were performed for 1369 genes that gave unsupportive WBs in the initial screening using cell lysates with overexpressed full-length proteins. Then, more than 82% of the antibodies yielded a specific band corresponding to the full-length protein. Hence, the vast majority of the antibodies (90%) used in this study specifically recognize the target protein when present at sufficiently high levels. This demonstrates the context- and application-dependence of antibody validation and emphasizes that caution is needed when annotating binding reagents as specific or cross-reactive. WB is one of the most commonly used methods for validation of antibodies. Our data implicate that solely using one platform for antibody validation might give misleading information and therefore at least one additional method should be used to verify the achieved data.
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