scholarly journals Reproducible Discovery of Cell-Binding Peptides "Lost" in Bulk Amplification via Emulsion Amplification in Phage Display Panning

2021 ◽  
Author(s):  
Wadim L Matochko ◽  
Frederique Deiss ◽  
Yang Yang ◽  
Ratmir Derda

Many pharmaceutically-relevant cell surface receptors are functional only in the context of intact cells. Phage display, while being a powerful method for the discovery of ligands for purified proteins often fails to identify a diverse set of ligands to receptors on a cell membrane mosaic. To understand this deficiency, we examined growth bias in naive phage display libraries and observed that it fundamentally changes selection outcomes: The presence of growth-biased (parasite) phage clones in a phage library is detrimental to selection and cell-based panning of such biased libraries is poised to yield ligands from within a small parasite population. Importantly, amplification of phage libraries in water-oil emulsions suppressed the amplification of parasites and steered the selection of biased phage libraries away from parasite population. Attenuation of the growth bias through the use of emulsion amplification reproducibly discovers the ligands for cell-surface receptors that cannot be identified in screen that use conventional "bulk" amplification.

2003 ◽  
Vol 31 (5) ◽  
pp. 1028-1031 ◽  
Author(s):  
R.J. Cherry ◽  
I.E.G. Morrison ◽  
I. Karakikes ◽  
R.E. Barber ◽  
G. Silkstone ◽  
...  

SPFI (single-particle fluorescence imaging) uses the high sensitivity of fluorescence to visualize individual molecules that have been selectively labelled with small fluorescent particles. The images of particles are diffraction-limited spots that are analysed by fitting with a two-dimensional Gaussian function. The spot intensities depend on whether they arise from one or more particles; this provides the basis for determining self-association of cell-surface receptors. We have used this approach to determine dimerization of MHC class II molecules and its disruption by interface peptides. We have also exploited the positional information obtained from SPFI to detect co-localization of cell-surface molecules. This involves labelling two different molecules with different coloured fluorophores and determining their positions separately by dual wavelength imaging. The images are analysed to quantify the overlap of the particle images and hence determine the extent of co-localization of the labelled molecules. The technique provides quantification of the extent of co-localization and can detect whether co-localized molecules occur singly or in clusters. We have obtained preliminary data for co-localization of lipopolysaccharide and CD14 on intact cells. We also show that HLA-DR (human leukocyte antigen-DR) and CD74 are partially co-localized and that interaction between these molecules involves the peptide-binding groove of HLA-DR.


Small ◽  
2015 ◽  
Vol 11 (8) ◽  
pp. 1012-1012
Author(s):  
Ramesh Ramji ◽  
Cheong Fook Cheong ◽  
Hiroaki Hirata ◽  
Abdur Rub Abdur Rahman ◽  
Chwee Teck Lim

2020 ◽  
Vol 11 (16) ◽  
pp. 4221-4225 ◽  
Author(s):  
Jing Qi ◽  
Weishuo Li ◽  
Xiaoling Xu ◽  
Feiyang Jin ◽  
Di Liu ◽  
...  

Cell-surface polymerization of anti-CD20 aptamer modified macromer to induce CD20 receptor clustering, and effectively initiate the apoptotic signals in cells.


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