Formatted anti-tumor necrosis factor alpha VHH proteins derived from camelids show superior potency and targeting to inflamed joints in a murine model of collagen-induced arthritis.
OBJECTIVE
The advent of tumor necrosis factor (TNF)-blocking drugs has provided rheumatologists with an effective, but highly expensive, treatment for the management of established rheumatoid arthritis (RA). Our aim was to explore preclinically the application of camelid anti-TNF VHH proteins, which are single-domain antigen binding (VHH) proteins homologous to human immunoglobulin V(H) domains, as TNF antagonists in a mouse model of RA.


METHODS
Llamas were immunized with human and mouse TNF, and antagonistic anti-TNF VHH proteins were isolated and cloned for bacterial production. The resulting anti-TNF VHH proteins were recombinantly linked to yield bivalent mouse and human TNF-specific molecules. To increase the serum half-life and targeting properties, an anti-serum albumin anti-TNF VHH domain was incorporated into the bivalent molecules. The TNF-neutralizing potential was analyzed in vitro. Mouse TNF-specific molecules were tested in a therapeutic protocol in murine collagen-induced arthritis (CIA). Disease progression was evaluated by clinical scoring and histologic evaluation. Targeting properties were evaluated by 99mTc labeling and gamma camera imaging.


RESULTS
The bivalent molecules were up to 500 times more potent than the monovalent molecules. The antagonistic potency of the anti-human TNF VHH proteins exceeded even that of the anti-TNF antibodies infliximab and adalimumab that are used clinically in RA. Incorporation of binding affinity for albumin into the anti-TNF VHH protein significantly prolonged its serum half-life and promoted its targeting to inflamed joints in the murine CIA model of RA. This might explain the excellent therapeutic efficacy observed in vivo.


CONCLUSIONS
These data suggest that because of the flexibility of their format, camelid anti-TNF VHH proteins can be converted into potent therapeutic agents that can be produced and purified cost-effectively.
Coppieters
Ken
K
Ghent University and Flanders Interuniversity Institute for Biotechnology (VIB), Zwijnaarde, Belgium.
Dreier
Torsten
T
Silence
Karen
K
de Haard
Hans
H
Lauwereys
Marc
M
Casteels
Peter
P
Beirnaert
Els
E
Jonckheere
Heidi
H
Van de Wiele
Christophe
C
Staelens
Ludovicus
L
Hostens
Jeroen
J
Revets
Hilde
H
Remaut
Erik
E
Elewaut
Dirk
D
Rottiers
Pieter
P
D000068879:Adalimumab; D000818:Animals; D000906:Antibodies / Q000276:immunology / Q000627:therapeutic use; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001169:Arthritis, Experimental / Q000628:therapy*; D002161:Camelids, New World / Q000276:immunology; D006207:Half-Life; D007143:Immunoglobulin Heavy Chains / Q000097:blood / Q000276:immunology* / Q000627:therapeutic use*; D007135:Immunoglobulin Variable Region / Q000097:blood / Q000276:immunology* / Q000627:therapeutic use*; D000069285:Infliximab; D051379:Mice; D008807:Mice, Inbred BALB C; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
D000906:Antibodies; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D014409:Tumor Necrosis Factor-alpha; D000069285:Infliximab; D000068879:Adalimumab