Analysis of binding residues in monoclonal antibody with high affinity for the head domain of the rat P2X4 receptor

2020 ◽  
Author(s):  
Tatsuhiro Igawa ◽  
Shuhei Kishikawa ◽  
Yoshito Abe ◽  
Makoto Tsuda ◽  
Kazuhide Inoue ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Neuropathic Pain ◽  
Monoclonal Antibodies ◽  
Dissociation Constants ◽  
Site Directed Mutagenesis ◽  
P2x4 Receptor ◽  
High Affinity ◽  
Head Domain ◽  
Binding Residues ◽  
Nanomolar Range

Abstract P2X4 receptor is known to be involved in neuropathic pain. In order to detect the expression of P2X4 receptor on microglia at the time of onset of neuropathic pain, one approach consists on the preparation of the monoclonal antibodies with both selective binding and high affinity. We have recently established a monoclonal antibody (named 12-10H) which had high affinity to rat P2X4 receptor expressed in 1321N1 cells. The dissociation constants of the complex between the monoclonal antibodies obtained so far and the head domain (HD) in the rat P2X4 receptor were in the nanomolar range. To improve the affinity by rational mutations, we need to know the precious location of the binding site in these monoclonal antibodies. Here, we have analysed and identified the binding residues in the monoclonal antibody (12-10H) with high affinity for the HD of the rat P2X4 receptor by site-directed mutagenesis.

scholarly journals Improvement of the affinity of an anti-rat P2X4 receptor antibody by introducing electrostatic interactions

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Chinatsu Shinozaki ◽  
Keita Kohno ◽  
Mitsunori Shiroishi ◽  
Daisuke Takahashi ◽  
Yu Yoshikawa ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Monoclonal Antibody ◽  
Neuropathic Pain ◽  
Electrostatic Interactions ◽  
Hot Spot ◽  
Neonatal Rat ◽  
Variable Regions ◽  
P2x4 Receptor ◽  
Head Domain ◽  
Arginine Residues

AbstractWe have recently developed a mouse monoclonal antibody (12–10H) binding to the head domain region in rat P2X4 receptor (rP2X4R, which is crucial for the pathogenesis of neuropathic pain) expressed on the cell with the highest binding affinity (KD = 20 nM). However, the 12–10H antibody failed to detect endogenously expressed P2X4Rs in microglia isolated from the spinal cord of rats whose spinal nerves were injured. Then, we prepared R5 mutant, in which five arginine residues were introduced into variable regions except for the “hot spot” in the 12–10H antibody to increase electrostatic interactions with the head domain, an anionic region, in rP2X4R. The mutation resulted in an increase of 50-fold in the affinity of the R5 mutant for the head domain with respect to the intact 12–10H antibody. As a result, detection of P2X4Rs endogenously expressed on primary cultured microglial cells originated from the neonatal rat brain and spinal cord microglia isolated from a rat model of neuropathic pain was achieved. These findings suggest a strategy to improve the affinity of a monoclonal antibody for an anionic antigen by the introduction of several arginine residues into variable regions other than the “hot spot” in the paratope.

scholarly journals Identification of Residues within Human Glycoprotein VI Involved in the Binding to Collagen

2004 ◽  
Vol 279 (50) ◽  
pp. 52293-52299 ◽  
Author(s):  
Christelle Lecut ◽  
Véronique Arocas ◽  
Hans Ulrichts ◽  
Anthony Elbaz ◽  
Jean-Luc Villeval ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Molecular Modeling ◽  
Binding Sites ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Binding Assays ◽  
Glycoprotein Vi ◽  
Ligand Binding Sites ◽  
Human Receptor

Glycoprotein VI (GPVI) has a crucial role in platelet responses to collagen. Still, little is known about its interaction with its ligands. In binding assays using soluble or cell-expressed human GPVI, we observed that (i) collagen, and the GPVI-specific ligands collagen-related peptides (CRP) and convulxin, competed with one another for the binding to GPVI and (ii) monoclonal antibodies directed against the extracellular part of the human receptor displayed selective inhibitory properties on GPVI interaction with its ligands. Monoclonal antibody 9E18 strongly reduced the binding of GPVI to collagen/CRP, 3F8 inhibited its interaction with convulxin, whereas 9O12 prevented all three interactions. These observations suggest that ligand-binding sites are distinct, exhibiting specific features but at the same time also sharing some common residues participating in the recognition of these ligands. The epitope of 9O12 was mapped by phage display, along with molecular modeling of human GPVI, which allowed the identification of residues within GPVI potentially involved in ligand recognition. Site-directed mutagenesis revealed that valine 34 and leucine 36 are critical for GPVI interaction with collagen and CRP. The loop might thus be part of a collagen/CRP-binding site.

Identification of a binding site on human FGF-2 for fibrinogen

Blood ◽  
2004 ◽  
Vol 103 (6) ◽  
pp. 2114-2120 ◽  
Author(s):  
Hu Peng ◽  
Abha Sahni ◽  
Philip Fay ◽  
Stephen Bellum ◽  
Igor Prudovsky ◽  
...  
Keyword(s):  
Binding Site ◽  
Structural Changes ◽  
Dissociation Constants ◽  
Site Directed Mutagenesis ◽  
Affinity Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
The Third ◽  
Fibrinogen Binding ◽  
Adhesive Interactions

Abstract Endothelial cell adhesive interactions are mediated by both fibrinogen and fibrin, and growth is stimulated by fibroblast growth factor 2 (FGF-2). We have shown previously that FGF-2 binds specifically and with high affinity to fibrinogen and fibrin and that fibrinogen potentiates the proliferative capacity of FGF-2 and also protects it from proteolytic degradation. To further characterize this interaction we have performed FGF-2 mutagenesis to identify the interactive site. Because FGF-1 has a similar structure to FGF-2 but does not bind to fibrinogen, we used a strategy of cassette and site-directed mutagenesis, exchanging residues from FGF-1 and FGF-2 and correlating structural changes with fibrinogen binding. Two cassette interchange mutants, 2212 and 2211, contained either the third cassette or both the third and fourth cassettes from FGF-1, and neither exhibited any affinity for fibrinogen. Exchange of 5 residues (Phe95, Ser100, Asn102, Arg107, and Arg109) from FGF-2 into the corresponding sites in the third cassette of FGF-1 imparted high-affinity binding with apparent dissociation constants (Kd) of 5.3 nM and 8.6 nM, respectively, compared with 1.3 nM for wild-type FGF-2. We conclude that these 5 residues define a high-affinity binding site in FGF-2 for fibrinogen.

Efficacy and specificity of monoclonal antibodies to progesterone in preventing the establishment of pregnancy in the mouse

1988 ◽  
Vol 118 (1) ◽  
pp. 69-80 ◽  
Author(s):  
S. T. Ellis ◽  
R. B. Heap ◽  
A. R. Butchart ◽  
V. Rider ◽  
N. E. Richardson ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Effective Dose ◽  
Half Life ◽  
Slow Rate ◽  
Affinity Constant ◽  
High Affinity ◽  
Mouse Immunoglobulin ◽  
High Concentrations ◽  
Ig G

ABSTRACT Anti-progesterone monoclonal antibody prevents the establishment of pregnancy in BALB/c mice by the prevention of implantation when injected i.p. 32 h after mating. To determine the specificity of this effect, mice were injected with immune and non-immune purified mouse immunoglobulins. The results show that anti-implantation efficacy was due to high-affinity antibody which bound progesterone since two further mouse immunoglobulin (Ig) G1 preparations, mouse IgA and mouse IgM which failed to bind the steroid, had no effect on pregnancy rates. From a panel of anti-progesterone monoclonal antibodies, six with a high affinity (affinity constant, 0·24–0·80 litres/nmol) and specificity for progesterone were selected for additional studies. Anti-implantation efficacy for five antibodies was similar, with a 50% effective dose within the range of 0·8–2·0 nmol. Antibody reached high concentrations in plasma within 12 h after i.p. injection, and declined with a half-life of about 80 h. Purified F(ab′)2 fragments of antibody also bound progesterone, but were less effective than the native molecule in blocking pregnancy. The results show that implantation in the mouse can be blocked by a high-affinity antibody that binds progesterone and which is removed from the blood at a slow rate. J. Endocr. (1988) 118, 69–80

scholarly journals Towards Dewetting Monoclonal Antibodies for Therapeutical Purposes

2019 ◽  
Author(s):  
Arturo Tozzi
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Ion Channels ◽  
Influenza A ◽  
Water Molecules ◽  
Transient Phenomenon ◽  
Water Flows ◽  
High Affinity ◽  
Channel Blockage ◽  
Severe Impairment

Dewetting transition - a concept borrowed from fluid mechanics -  is a physiological process which takes place inside the hydrophobic pores of ion channels.  This transient phenomenon causes a metastable state which forbids water molecules to cross the microscopic receptors’ cavities.  This leads to a decrease of conductance, a closure of the hole and, subsequently, severe impairment of cellular performance.  We suggest that  artificially-provoked dewetting transition in ion channels’ hydrophobic pores could stand for a molecular candidate to erase detrimental organisms, such as viruses, bacteria and cancer cells.  We describe a novel type of high-affinity monoclonal antibody, which: a) targets specific trans-membrane receptor structures of harmful or redundant cells; b) is equipped with lipophilic and/or hydrophobic fragments that prevent physiological water flows inside ion channels.  Therefore, we achieve an artificial dewetting transition inside receptors’ cavities which causes transmembrane ionic flows discontinuity, channel blockage and subsequent damage of morbid cells.  As an example, we describe dewetting monoclonal antibodies targeting the M2 channel of the Influenza A virus: they might prevent water to enter the pores, thus leading to virion impairment.

scholarly journals Exceptionally Potent Neutralization of Middle East Respiratory Syndrome Coronavirus by Human Monoclonal Antibodies

2014 ◽  
Vol 88 (14) ◽  
pp. 7796-7805 ◽  
Author(s):  
Tianlei Ying ◽  
Lanying Du ◽  
Tina W. Ju ◽  
Ponraj Prabakaran ◽  
Candy C. Y. Lau ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Middle East ◽  
High Mortality ◽  
Dissociation Constants ◽  
Rapid Identification ◽  
Middle East Respiratory Syndrome ◽  
Site Directed Mutagenesis ◽  
Antibody Library ◽  
Human Monoclonal Antibodies ◽  
Receptor Binding Site

ABSTRACTThe recently discovered Middle East respiratory syndrome coronavirus (MERS-CoV) continues to infect humans, with high mortality. Specific, highly effective therapeutics and vaccines against the MERS-CoV are urgently needed to save human lives and address the pandemic concerns. We identified three human monoclonal antibodies (MAbs), m336, m337, and m338, targeting the receptor (CD26/DPP4) binding domain (RBD) of the MERS-CoV spike glycoprotein from a very large naïve-antibody library (containing ∼1011antibodies). They bound with high affinity: equilibrium dissociation constants for the three MAbs were equal to 4.2, 9.3, and 15 nM, respectively, as measured by Biacore for Fabs binding to RBD. The avidity for IgG1 m336, m337, and m338 was even higher: 99, 820, and 560 pM, respectively. The antibodies bound to overlapping epitopes that overlap the receptor binding site on the RBD as suggested by competition experiments and further supported by site-directed mutagenesis of the RBD and a docking model of the m336-RBD complex. The highest-affinity MAb, m336, neutralized both pseudotyped and live MERS-CoV with exceptional potency, 50% neutralization at 0.005 and 0.07 μg/ml, respectively, likely by competing with DPP4 for binding to the S glycoprotein. The exceptionally high neutralization activity of these antibodies and especially m336 suggests that they have great potential for prophylaxis and therapy of MERS-CoV infection in humans and as a tool for development of vaccine immunogens. The rapid identification (within several weeks) of potent MAbs suggests a possibility to use the new large antibody library and related methodology for a quick response to the public threat resulting from emerging coronaviruses.IMPORTANCEA novel human coronavirus, the Middle East respiratory syndrome coronavirus (MERS-CoV), was found to infect humans with a high mortality rate in 2012, just 1 decade after the appearance of the first highly pathogenic coronavirus, severe acute respiratory syndrome coronavirus (SARS-CoV). There are no effective therapeutics available. It is highly desirable to find an approach for rapidly developing potent therapeutics against MERS-CoV, which not only can be implemented for MERS treatment but also can help to develop a platform strategy to combat future emerging coronaviruses. We report here the identification of human monoclonal antibodies (MAbs) from a large nonimmune antibody library that target MERS-CoV. One of the antibodies, m336, neutralized the virus with exceptional potency. It therefore may have great potential as a candidate therapeutic and as a reagent to facilitate the development of vaccines against MERS-CoV.

Two-monoclonal-antibody sandwich-type assay for thyrotropin, with use of an avidin-biotin separation technique.

1986 ◽  
Vol 32 (10) ◽  
pp. 1873-1878 ◽  
Author(s):  
W D Odell ◽  
J Griffin ◽  
R Zahradnik
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
The Other ◽  
Separation Technique ◽  
Simple Method ◽  
Polystyrene Beads ◽  
High Affinity ◽  
Antigenic Sites ◽  
Free Antibody ◽  
Sandwich Type

Abstract We have developed a sensitive, specific, noncompetitive, sandwich-type radioimmunoassay for human thyrotropin (hTSH), which can be performed in 30 min. The assay involves two monoclonal antibodies, selected for high affinity and specificity and also for reaction against antigenic sites on hTSH that are distal from each other. One of these antibodies is labeled with 125I; the other is conjugated covalently to biotin. Polystyrene beads were also conjugated covalently to biotin. After conjugation, the beads were incubated with avidin. These beads represent a rapid, simple method for separating hTSH-bound antibody from free antibody. The biotin-antibody-hTSH-125I-labeled antibody complexes bind to the beads and hTSH concentration is directly related to counts per minute. This assay can detect hTSH at a concentration of 0.06 milli-unit/L in serum.

Rapid quantification and in situ detection of nitrifying bacteria in biofilms by monoclonal antibody method

2000 ◽  
Vol 41 (4-5) ◽  
pp. 301-308 ◽  
Author(s):  
N. Noda ◽  
H. Ikuta ◽  
Y. Ebie ◽  
A. Hirata ◽  
S. Tsuneda ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Fluorescent Antibody ◽  
Nitrifying Bacteria ◽  
Fluorescent Antibody Technique ◽  
Antibody Technique ◽  
Antibody Method ◽  
In Situ Detection ◽  
Rapid Quantification

Fluorescent antibody technique by the monoclonal antibody method is very useful and helpful for the rapid quantification and in situ detection of the specific bacteria like nitrifiers in a mixed baxterial habitat such as a biofilm. In this study, twelve monoclonal antibodies against Nitrosomonas europaea (IFO14298) and sixteen against Nitrobacter winogradskyi (IFO14297) were raised from splenocytes of mice (BALB/c). It was found that these antibodies exhibited little cross reactivity against various kinds of heterotrophic bacteria. The direct cell count method using monoclonal antibodies could exactly detect and rapidly quantify N. europaea and N. winogradskyi. Moreover, the distribution of N. europaea and N. winogradskyi in a biofilm could be examined by in situ fluorescent antibody technique. It was shown that most of N. winogradskyi existed near the surface part and most of N. europaea existed at the inner part of the polyethylene glycol (PEG) gel pellet, which had entrapped activated sludge and used in a landfill leachate treatment reactor. It was suggested that this monoclonal antibody method was utilized for estimating and controlling the population of nitrifying bacteria as a quick and favorable tool.

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