CXCR4 nanobodies (VHH-based single variable domains) potently inhibit chemotaxis and HIV-1 replication and mobilize stem cells.
The important family of G protein-coupled receptors has so far not been targeted very successfully with conventional monoclonal antibodies. Here we report the isolation and characterization of functional VHH-based immunoglobulin single variable domains (or nanobodies) against the chemokine receptor CXCR4. Two highly selective monovalent nanobodies, 238D2 and 238D4, were obtained using a time-efficient whole cell immunization, phage display, and counterselection method. The highly selective VHH-based immunoglobulin single variable domains competitively inhibited the CXCR4-mediated signaling and antagonized the chemoattractant effect of the CXCR4 ligand CXCL12. Epitope mapping showed that the two nanobodies bind to distinct but partially overlapping sites in the extracellular loops. Short peptide linkage of 238D2 with 238D4 resulted in significantly increased affinity for CXCR4 and picomolar activity in antichemotactic assays. Interestingly, the monovalent nanobodies behaved as neutral antagonists, whereas the biparatopic nanobodies acted as inverse agonists at the constitutively active CXCR4-N3.35A. The CXCR4 nanobodies displayed strong antiretroviral activity against T cell-tropic and dual-tropic HIV-1 strains. Moreover, the biparatopic nanobody effectively mobilized CD34-positive stem cells in cynomolgus monkeys. Thus, the nanobody platform may be highly effective at generating extremely potent and selective G protein-coupled receptor modulators.
Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, 1081 HV Amsterdam, The Netherlands.
Sven
S
Jähnichen
Christophe
C
Blanchetot
David
D
Maussang
Maria
M
Gonzalez-Pajuelo
Ken Y
KY
Chow
Leontien
L
Bosch
Sindi
S
De Vrieze
Benedikte
B
Serruys
Hans
H
Ulrichts
Wesly
W
Vandevelde
Michael
M
Saunders
Hans J
HJ
De Haard
Dominique
D
Schols
Rob
R
Leurs
Peter
P
Vanlandschoot
Theo
T
Verrips
Martine J
MJ
Smit
D000818:Animals; D000906:Antibodies / Q000302:isolation & purification / Q000494:pharmacology*; D018952:Antigens, CD34; D001596:Benzylamines; D001665:Binding Sites / Q000235:genetics; D019556:COS Cells; D002633:Chemotaxis / Q000187:drug effects*; D002522:Chlorocebus aethiops; D000080027:Cyclams; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D057809:HEK293 Cells; D015497:HIV-1; D019650:Hematopoietic Stem Cell Mobilization; D006571:Heterocyclic Compounds; D006801:Humans; D019718:Receptors, CXCR4 / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014779:Virus Replication / Q000187:drug effects*
D000906:Antibodies; D018952:Antigens, CD34; D001596:Benzylamines; C527276:CXCR4 protein, human; D000080027:Cyclams; D006571:Heterocyclic Compounds; D019718:Receptors, CXCR4; C088327:plerixafor