scholarly journals Isolation of highly selective IgNAR variable single-domains against a human therapeutic Fc scaffold and their application as tailor-made bioprocessing reagents

2019 ◽  
Vol 32 (9) ◽  
pp. 385-399
Author(s):  
Magdalena J Buschhaus ◽  
Stefan Becker ◽  
Andrew J Porter ◽  
Caroline J Barelle
Keyword(s):  
Phage Display ◽  
Adaptive Immune System ◽  
Adaptive Immune ◽  
Ideal Candidate ◽  
Naturally Occurring ◽  
Physicochemical Stability ◽  
Classical Immunoglobulin ◽  
Cryptic Epitopes ◽  
By Products ◽  
Selection Of

Abstract The adaptive immune system of cartilaginous fish (Elasmobranchii), comprising of classical hetero-tetrameric antibodies, is enhanced through the presence of a naturally occurring homodimeric antibody-like immunoglobulin—the new antigen receptor (IgNAR). The binding site of the IgNAR variable single-domain (VNAR) offers advantages of reduced size (<1/10th of classical immunoglobulin) and extended binding topographies, making it an ideal candidate for accessing cryptic epitopes otherwise intractable to conventional antibodies. These attributes, coupled with high physicochemical stability and amenability to phage display, facilitate the selection of VNAR binders to challenging targets. Here, we explored the unique attributes of these single domains for potential application as bioprocessing reagents in the development of the SEED-Fc platform, designed to generate therapeutic bispecific antibodies. A panel of unique VNARs specific to the SEED homodimeric (monospecific) ‘by-products’ were isolated from a shark semi-synthetic VNAR library via phage display. The lead VNAR candidate exhibited low nanomolar affinity and superior selectivity to SEED homodimer, with functionality being retained upon exposure to extreme physicochemical conditions that mimic their applicability as purification agents. Ultimately, this work exemplifies the robustness of the semi-synthetic VNAR platform, the predisposition of the VNAR paratope to recognise novel epitopes and the potential for routine generation of tailor-made VNAR-based bioprocessing reagents.

scholarly journals In Pursuit of Adult Progenitors of Thymic Epithelial Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Tatsuya Ishikawa ◽  
Nobuko Akiyama ◽  
Taishin Akiyama
Keyword(s):  
T Cells ◽  
Epithelial Cells ◽  
Adaptive Immune System ◽  
Thymic Epithelial Cells ◽  
Adaptive Immune ◽  
Peripheral T Cells ◽  
Robust Adaptive ◽  
Adult Thymus ◽  
Shed Light ◽  
Selection Of

Peripheral T cells capable of discriminating between self and non-self antigens are major components of a robust adaptive immune system. The development of self-tolerant T cells is orchestrated by thymic epithelial cells (TECs), which are localized in the thymic cortex (cortical TECs, cTECs) and medulla (medullary TECs, mTECs). cTECs and mTECs are essential for differentiation, proliferation, and positive and negative selection of thymocytes. Recent advances in single-cell RNA-sequencing technology have revealed a previously unknown degree of TEC heterogeneity, but we still lack a clear picture of the identity of TEC progenitors in the adult thymus. In this review, we describe both earlier and recent findings that shed light on features of these elusive adult progenitors in the context of tissue homeostasis, as well as recovery from stress-induced thymic atrophy.

scholarly journals Comprehensive Mining and Characterization of CRISPR-Cas Systems in Bifidobacterium

2020 ◽  
Vol 8 (5) ◽  
pp. 720 ◽  
Author(s):  
Meichen Pan ◽  
Matthew A. Nethery ◽  
Claudio Hidalgo-Cantabrana ◽  
Rodolphe Barrangou
Keyword(s):  
Genome Engineering ◽  
Rare Variants ◽  
Adaptive Immune System ◽  
Effector Proteins ◽  
Type I ◽  
Human Gut ◽  
Adaptive Immune ◽  
Naturally Occurring ◽  
History Of

The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas (CRISPR-associated cas) systems constitute the adaptive immune system in prokaryotes, which provides resistance against bacteriophages and invasive genetic elements. The landscape of applications in bacteria and eukaryotes relies on a few Cas effector proteins that have been characterized in detail. However, there is a lack of comprehensive studies on naturally occurring CRISPR-Cas systems in beneficial bacteria, such as human gut commensal Bifidobacterium species. In this study, we mined 954 publicly available Bifidobacterium genomes and identified CRIPSR-Cas systems in 57% of these strains. A total of five CRISPR-Cas subtypes were identified as follows: Type I-E, I-C, I-G, II-A, and II-C. Among the subtypes, Type I-C was the most abundant (23%). We further characterized the CRISPR RNA (crRNA), tracrRNA, and PAM sequences to provide a molecular basis for the development of new genome editing tools for a variety of applications. Moreover, we investigated the evolutionary history of certain Bifidobacterium strains through visualization of acquired spacer sequences and demonstrated how these hypervariable CRISPR regions can be used as genotyping markers. This extensive characterization will enable the repurposing of endogenous CRISPR-Cas systems in Bifidobacteria for genome engineering, transcriptional regulation, genotyping, and screening of rare variants.

Maladaptation to mental stress mitigated by the adaptive immune system via depletion of naturally occurring regulatory CD4+CD25+ cells

2006 ◽  
Vol 66 (6) ◽  
pp. 552-563 ◽  
Author(s):  
Hagit Cohen ◽  
Yaniv Ziv ◽  
Michal Cardon ◽  
Zeev Kaplan ◽  
Michael A. Matar ◽  
...  
Keyword(s):  
Immune System ◽  
Mental Stress ◽  
Adaptive Immune System ◽  
Adaptive Immune ◽  
Naturally Occurring

scholarly journals The CRISPR/Cas Adaptive Immune System of Pseudomonas aeruginosa Mediates Resistance to Naturally Occurring and Engineered Phages

2012 ◽  
Vol 194 (21) ◽  
pp. 5728-5738 ◽  
Author(s):  
K. C. Cady ◽  
J. Bondy-Denomy ◽  
G. E. Heussler ◽  
A. R. Davidson ◽  
G. A. O'Toole
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Immune System ◽  
Adaptive Immune System ◽  
Adaptive Immune ◽  
Naturally Occurring

Selection of naturally occurring autoantibodies to interleukin-18 from phage display library

2010 ◽  
Vol 19 (2-3) ◽  
pp. 71-78 ◽  
Author(s):  
M.A. Vikhrova ◽  
M.V. Shveygert ◽  
E.A. Khrapov ◽  
M.L. Filipenko ◽  
I.P. Gileva ◽  
...  
Keyword(s):  
Phage Display ◽  
Phage Display Library ◽  
Interleukin 18 ◽  
Naturally Occurring ◽  
Selection Of

Do parasites live in extreme environments? Constructing hostile niches and living in them

Parasitology ◽  
1999 ◽  
Vol 119 (S1) ◽  
pp. S107-S110 ◽  
Author(s):  
C. Combes ◽  
S. Morand
Keyword(s):  
Immune System ◽  
Extreme Environments ◽  
Adaptive Immune System ◽  
Antibody Repertoire ◽  
Arms Races ◽  
Counter Measures ◽  
Mhc Molecules ◽  
Adaptive Immune ◽  
Parasite Populations ◽  
Selection Of

SUMMARYWe develop the hypothesis that parasites do not invade extreme environments, i.e. hostile hosts, but rather ‘create’ them. We argue that parasites may have driven the evolution of the constitutive and adaptive immune system. This leads to several implications. First, parasites respond to ‘genes to kill’ by ‘genes to survive’ and this triggers an indefinite selection of measures and counter-measures. Second, these revolutionary arms races may lead to local adaptation, in which parasite populations perform better on local hosts. Third, the evolution of the immune system, whose responses are predictable, may allow parasites to specialize, to evade and even to manipulate. Finally we show that the correlations between the increase in the antibody repertoire, the expansion of MHC loci and parasite pressures support our hypothesis that both host complexity and parasite pressures can be invoked to explain the diversity of antibodies, T-receptors and MHC molecules.

Evolution and age characteristics of the innate and adaptive immune system

2016 ◽  
Vol 75 (3) ◽  
pp. 74-84 ◽  
Author(s):  
A.E. Abaturov ◽  
◽  
E.A. Agafonova ◽  
N.I. Abaturova ◽  
V.L. Babich ◽  
...  
Keyword(s):  
Immune System ◽  
Adaptive Immune System ◽  
Adaptive Immune

Combination of ribosome and phage display for fast selection of high affinity VHH antibody fragments

2019 ◽  
pp. 27-33
Author(s):  
YuE Kravchenko ◽  
SV Ivanov ◽  
DS Kravchenko ◽  
EI Frolova ◽  
SP Chumakov
Keyword(s):  
Phage Display ◽  
Selection Procedure ◽  
Free System ◽  
Phage Displays ◽  
High Affinity ◽  
Binding Domains ◽  
A Cell ◽  
Vhh Antibodies ◽  
Efficiency Of Selection ◽  
Selection Of

Selection of antibodies using phage display involves the preliminary cloning of the repertoire of sequences encoding antigen-binding domains into phagemid, which is considered the bottleneck of the method, limiting the resulting diversity of libraries and leading to the loss of poorly represented variants before the start of the selection procedure. Selection in cell-free conditions using a ribosomal display is devoid from this drawback, however is highly sensitive to PCR artifacts and the RNase contamination. The aim of the study was to test the efficiency of a combination of both methods, including pre-selection in a cell-free system to enrich the source library, followed by cloning and final selection using phage display. This approach may eliminate the shortcomings of each method and increase the efficiency of selection. For selection, alpaca VHH antibody sequences suitable for building an immune library were used due to the lack of VL domains. Analysis of immune libraries from the genes of the VH3, VHH3 and VH4 families showed that the VHH antibodies share in the VH3 and VH4 gene groups is insignificant, and selection from the combined library is less effective than from the VHH3 family of sequences. We found that the combination of ribosomal and phage displays leads to a higher enrichment of high-affinity fragments and avoids the loss of the original diversity during cloning. The combined method allowed us to obtain a greater number of different high-affinity sequences, and all the tested VHH fragments were able to specifically recognize the target, including the total protein extracts of cell cultures.

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