Alexander GabibovMechanisms of Antigen degradation
Workshop "Biomedical technologies at Skokovo. Opportunities and challenges"
Antigen degradationmachinery
AAntintiBBodiesodies
Catalytic Antibodies
ENENzymeszymes
ABzymesABzymes
Catalytic Antibodies. Historical Background
Five ways to obtain catalytic antibodies
Five ways to obtain catalytic antibodies
Immunization by transition
state analog of reaction
Production of antiidiotypicantibody
Reactive immunization
Induction of autoimmunedisease
Screening of phage-display libraries
Belogurov et al, BioEssays 2009
Organophosphorous poisons
The major target of organophosphorous toxins are cholinesterase-like enzymes;
Extremely low LD50 value
OPC-associated mortality is 200,000 people per year;
There are real threats of acts of terrorism, for example sarin attack in Tokyo underground at 20 March of 1995
9A8 may covalently accept and destroy anti-acetylcholine esterase poisons from blood stream 9A8 may covalently accept and destroy anti-acetylcholine esterase poisons from blood stream
Kolesnikov et al, PNAS 2000
3D Structure of the 9A8 Antiidiotypic Antibody Active Site
• Superposition of the active sites of esterolytic abzymes 9A8 (green) and 17E8 (blue).
• Ser99 - His35 diades are indicated.
• Hydrogene bonds are indicated by dashed lines.
Soman
r9A8 interact with soman-MCA
RFU
Time, h
Combinatorial approachRational design
High resolution 3D Effective screening
Directed evolution
-streptavidin molecule
-BSA molecule
-Biotin group
-Phosphonate group
Control wellExperimental well
Phage pull after reaction with Bt-X
phosphonate
Nonspecific sorbsion
Nonspecific and
specific sorbsion
Trypsin elution
Phage amplificatio
n
Next rounds of selection
Bt-X
Reactive (covalent) selection
A.17 Catalytic Antibody
Biotin-X-phosphonate
Griffin.1 scFv library
+
Screening for biotin-X binding
Conversion into the full-size human antibody
crystal
Reshetnyak et al, JACS 2007
A.17 antibody has unusual deep cavity with nucleophilic tyrosine at its base
A.17 antibody has unusual deep cavity with nucleophilic tyrosine at its base
Comparison of active site cavities of natural and created de novo biocatalysts. Chemically selected reactibody A.17 possess deepest substrate binding niche. Cross-section views of the active center of esterolytic antibodies 49G7, TEPC15, aldolase antibody 33F12, choline esterases AChE and BChE and antibody A.17 complexed with their ligands.
Tyr59
Tyr53
Tyr33
Tyr34
Trp109 Tyr37
Trp92
Trp48
Phe100
OP compound
P
O
O
O
NO2
HN
Tyr37
OH
P(R)
P
O
OO
HN
Tyr37
P(S)
SN2
Tyr59Tyr53
Tyr33
Tyr34
Trp109
Asn105
Ala107
Phe100
Trp92
Trp48
Cl-
2.5 Å 3.3 Å
3.2 Å
Ser51
2.8 Å
Tyr37
The pre-existing primitive active site of the A.17 antibody stereo-selectively interacts with P(R)-isomer of the phosphonate molecule
TyrTyr
+Tyr
Tyr
TyrTyr
++
A.17 antibody hydrolyzes organophosphorus pesticide – paraoxon by multi-step covalent catalysis.
Covalent intermediate
Amount of released p-nitrophenol in case of the reaction with paraoxon is evidently higher than
concentration of active sites
The reaction rate increased linearly with hydroxylamine concentration. It allows to define that
dephosphorylation is rate limiting step
k2 = 1.1 ± 0.1 x10-1 min-1
k3 = 1.6 ± 0.2 x10-2 min-1
k4 = 1.26 ± 0.09 x10-3 min-1
1576.3
1578.530+
1579.430+
1580.330+
1581.331+
1584.21585.9
1590.930+
1591.830+
1592.7 1593.81603.2
19+
1575 1580 1585 1590 1595 1600 1605 m/z0.0
0.5
1.0
1.5
2.0
8x10Intens.
FAB_A17_000001.d: +MS
1578.430+
1580.915+
1583.030+
1584.230+
1585.9 1587.5 1589.0
1590.930+
1595.730+
1603.230+
1575 1580 1585 1590 1595 1600 1605 m/z0.00
0.25
0.50
0.75
1.00
1.25
1.50
8x10Intens.
FAB_A17_Paraoxon_000001.d: +MS
1578.5m/z=30
1578.5m/z=30
1583.0m/z=30
Δm=135 ( )
(unmodified Fab A.17)
(phosphonylated Fab A.17)
(unmodified Fab A.17)
The reaction mechanism of paraoxon hydrolysis by A.17 antibody proceeds through the phosphotyrosine covalent
intermediate.
Perspectives: generation of artificial biocatalysts in vivo
MESSAGE• Basically ALL Autoantigens may serve as substrates for autoantibodies. Kolesnikov et al. PNAS, 2000
Ponomarenko et al. Meth. Immunol., 2002Kozyr et al. Imm.Lett., 2002Ponomarenko et al. PNAS, 2006Ponomarenko et al. Biochemistry 2006Ponomarenko et al. Biochemistry, 2007Belogurov et al. J.Immunology, 2008Durova et al. Molecular Immunology, 2009Belogurov et al. Autoimmunity, 2009
Belogurov et al, BioEssays 2009
CDRH3
DNA
Possible catalytic residues
Schuster et al, Science, 1992, Gololobov et al, PNAS, 1995; Gololobov et al. Mol Immunol. 1997.
Structural Similarity Between BV04-01 and MRL-4 anti-DNA Autoantibodies: DNA-binding and DNA-cleaving Activities are
Germline-Encoded
Do Myelin-Directed Antibodies Predict Multiple Sclerosis?N EJM, 2003
The B-Cell – Old Player, New Position on the TeamNEJM, 2008
Multiple sclerosis
B-cells as one of the key players in the MS
Environmental hypothesis of MS induction. EBV virus involvement.
Environmental hypothesis of MS induction.EBV virus involvement.
Antibodies selected from MS Phage-display library are crossreactive towards both, Myelin Basic Protein and EBV latent membrane protein 1.
Abzymatic Site-Abzymatic Site-specific MBP specific MBP hydrolysishydrolysis
The cleavage sites are localized inside the encephalitogenic epitopes The cleavage sites are localized inside the encephalitogenic epitopes
MBPMBPMusse et al, PNAS 2006
Ponomarenko et al, PNAS 2006
Toxin
Autoreacti
veB-Cell
B-Cell Receptor (BCR), fragments of myelin basic protein (MBP)
BCR
MBPCD4CD25High TOLERANCE
Specific B-Cells depletion in MS
C D A B
Autoantibody binding pattern
Specific B-Cells depletion in MS
Fc-based immunotoxins are shown to be the best in the presented set due to the excellent specific/unspecific cytotoxicity ratio
MDS score versus days post disease induction (surrounding pictures). Peptides were applied at days 7-11 (120 μg/rat per day) after disease induction by nasal route. Maximum clinical score in each group of rats, median and 95% confidential interval (in the middle). NS - not significant
Belogurov et. al Autoimmunity
Administration of MBP peptides to DA rats with EAE
Clinical trials of MBP46-62 formulation in DA rats
• SUV liposomes 50-90 nm mimicking virus particles
• Interaction with APC cells • Dose-dependent effect
PP IPIP
The level of IP in the brain is dramatically elevated during EAEdevelopment in SJL/J mice.
Immunoproteasome localization in mice brain. LMP2 and LMP7 are carried by
different cells.
MBP hydrolysis by proteasome and enzymes. LC-ESI approach.
Enhanced release of encephalitogenic peptide by immunoproteasome. LC-ESI approach with isotope labeled
peptide.
• Immunoproteasome marks oligodendrocytes for CTL (immune system)
• Some kind of target designation
• How can we prevent this process? The answer is Inhibitors or siRNA
Expression of LMP7 immunosubunit is significantly decreased by siRNA
administration
Low-weight proteasome inhibitors
Low-weight inhibitors efficiently inhibit immunoproteasome in vitro and ameliorate EAE
in vivo
Immunoproteasome as a target for MS treatment
Der Mensch als Industriepalast (Man as Industrial Palace) Stuttgart, 1926. Chromolithograph. National Library of Medicine. Fritz Kahn (1888-1968) Kahn’s modernist visualization of the digestive and respiratory system as "industrial palace," really a chemical plant
M.M. Shemyakin & Yu.A. OvchinnikovInstitute of Bioorganic Chemistry,
Russian Academy of Sciences
Authors:
Alexandre G. Gabibov, Alexey A. Belogurov Jr., Ivan V. Smirnov, Inna N. Kurkova, Ekaterina Kuzina, Alexey Kononikhin, Alexey Stepanov, Natalie A. Ponomarenko, Andrey V. Reshetnyak
COLLABORATIONRUSSIA
Prof. Eugene NikolaevInstitute of Biochemical Physics RAS
Prof. Alexey BoykoMoscow MS Center
Prof. Dmitry Knorre,Prof. Olga Fedorova, Dr. Nikita Kuznetsov
Dr. Dmitry GenkinDr. Dobroslav Melamed
USAProf. Al Tramontano, UC Davis, Medical school
National Institute of Allergy and Infectious Diseases National Institutes of Health Dr. Herbert C. Morse III;Ciphergen Biosystems, Inc
FRANCEProf. Daniel Thomas, Alain Friboulet, Drs. Dominidue Pillet, Marjorie
Paon, Berangere Avalle.
The University of Technology, CompiegneProf. Patrick Masson, Drs Eugénie Carletti, Florian Nachon
Département de Toxicologie – CRSSA Institut de Recherche Biomédicale des Armées