4th Annual BMRP Investigator Meeting - Abstract

Treatment of Murine Colitis by Lactococcus lactis Secreting Anti-Tumor Necrosis Factor Nanobodies™

Klaas Vandenbroucke^1,a, Lynn Huyck¹, Jacques Van Huysse², Pieter Demetter², Torsten Dreier³, Els Beirnaert³, Marc Lauwereys³, Claude Cuvelier², Erik Remaut¹ and Pieter Rottiers<sup>1,b

1</sup>Department for Molecular Biomedical Research, Flanders Interuniversity Institute for Biotechnology (VIB) and Ghent University (Zwijnaarde, Belgium); ²Department of Pathology, Ghent University Hospital, Ghent University (Ghent, Belgium); ³Ablynx NV (Zwijnaarde, Belgium)

Background & aims: Crohn’s disease (CD) is a chronic inflammatory disorder that affects the gastrointestinal (GI) tract, caused by an inappropriate response of the body’s immune system. CD is a significant problem in the western societies, affecting one in 1000 individuals.  Systemic treatment of CD patients with antibodies against tumor necrosis factor (TNF) has shown to be promising and is now an approved therapy.  However, major drawbacks remain, such as hazardous side effects related to systemic administration and high treatment cost.  Local delivery of therapeutic proteins by in situ secretion in the intestine by genetically modified Lactococcus lactis provides an alternative approach for treatment of CD.

Methods: We have engineered the food grade bacterium Lactococcus lactis to secrete monovalent and bivalent murine (m)TNF neutralizing camelid antibody fragments
(anti-mTNF VHHs or anti-mTNF Nanobodies™).  Nanobodies™ are much more stable than conventional antibodies and can withstand harsh conditions such as those encountered in the GI-tract.  The therapeutic potential of these anti-mTNF Nanobodies™-secreting L. lactis was evaluated in the dextran sulfate sodium (DSS)-induced murine model for chronic colitis and in established chronic colitis in IL-10^-/- mice.  Disease was evaluated by blinded macroscopic and microscopic inflammatory scores and by myeloperoxidase activity.

Results: The L. lactis secreted anti-mTNF Nanobodies™ were able to efficiently neutralize soluble and membrane bound mTNF in vitro.  Daily intragastric administration of anti-mTNF Nanobodies™ -secreting L. lactis resulted in local and active delivery of  anti-mTNF Nanobodies™ at the mucosa of the colon.  No detectable levels of anti-TNF Nanobodies™ could be measured in the blood.  This approach proved to be very effective in reducing inflammation in the colon of mice with DSS-induced chronic colitis.  In addition, therapy was also successful in improving established chronic enterocolitis in IL-10-/- mice.

Conclusions: We have positively evaluated a new approach for treatment of chronic colitis in mice involving in situ secretion of anti-mTNF Nanobodies™ by orally administered L. lactis. Given the availability of anti-human TNF Nanobodies™, this novel therapeutic approach may lead to successful and cost-effective management of chronic colitis in IBD patients.

^aCo-investigator and Presenter; ^bPrincipal Investigator