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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_17 | Pages 24 - 24
24 Nov 2023
ANTIBODY-DRUG CONJUGATE THERAPY AGAINST S. AUREUS IMPLANT-ASSOCIATED INFECTION IN A MURINE MODEL
Tvilum A Johansen MI Glud L Malskær D Khamas A Carmali S Mhatre S Søgaard A Faddy E de Vor L Rooijakkers S Østergaard L Meyer R Zelikin A Jørgensen N
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Aim

Infections represent a serious threat to the successful utilization of implants in modern medicine. Implant-associated infections are difficult to treat, because they involve biofilms that protect bacteria from the immune system and harbour antibiotic-tolerant persister cells.

In this work, we developed an antibody-drug conjugate (ADC) containing the anti-neoplastic drug mitomycin C (MMC) as a novel treatment paradigm for implant-associated infections. MMC was chosen as it is a potent antimicrobial against biofilms and its synthesis into an ADC was chosen to alleviate toxicity. Following development and synthesis of the ADC, stability and release of MMC was measured. We then used the ADC to kill bacteria in suspension and in biofilms, in vitro and in vivo.

Method

Mitomycin C was conjugated to a commercially available antibody against S. aureus via a disulfide linkage, with a drug release occurred via thiol-disulfide exchange.

ADC as tested against S. aureus under various growth conditions (planktonic, persisters and biofilm). In vitro toxicity of ADC vs MMC was measured using a human cell line (MOLT-4).

Finally, two independent in vivo experiments were performed in a murine implant-associated osteomyelitis model. In experiment one ADC treatment was compared NaCl, vancomycin and vancomycin + ADC (n=10 for all groups). Subsequently, ADC was compared to NaCl, the antibody used in the ADC construction, MMC and a novel ADC constructed with a non-S. aureus antibody (n=10 for all groups). All treatments were started day 7 post inoculation and were administered for 3 days. CFU enumeration was done following sonication to quantify bacterial load.

Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_10 | Pages 31 - 31
1 Oct 2022
BIODISTRIBUTION OF A RADIO-LABELLED ANTIBODY TARGETING STAPHYLOCOCCUS AUREUS IMPLANT INFECTION IN MICE
v. Dijk B v. Duyvenbode FH de Vor L Nurmohamed FRHA Lam M Poot A Ramakers R Koustoulidou S Beekman F v. Strijp J Rooijakkers S Dadachova E Vogely HC Weinans H van der Wal BC
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Aim

Implant infections caused by Staphylococcus aureus are difficult to treat due to biofilm formation, which complicates surgical and antibiotic treatment. Herewith we introduce an alternative approach using monoclonal antibodies (mAbs) targeting S. aureus and provide the biodistribution and specificity in a mouse implant infection model.

Methods

4497-IgG1targeting S. aureus Wall Teichoic Acid was labeled to Indium-111 using “CHXA” as a chelator. SPECT-CT scans were performed at 24, 72 and 120 hours after administration in Balb/cAnNCrl mice with a subcutaneous implant pre-colonized with biofilm of S. aureus. Biodistribution over the various organs of this labelled antibody was visualized and quantified using SPECT-CT imaging and compared to uptake at the target tissue with implant infection.

Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_14 | Pages 25 - 25
1 Dec 2019
DEVELOPMENT OF ANTIBODIES THAT ENHANCE IMMUNE CLEARANCE OF STAPHYLOCOCCAL BIOFILMS
de Vor L Van Kessel K De Haas C Aerts P Viveen M Boel E Fluit A van Dijk B Vogely C van der Wal B van Strijp J Weinans H Rooijakkers S
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Aim

“Implant associated Staphylococcus aureus or S. epidermidis infections are often difficult to treat due to the formation of biofilms on prosthetic material. Biofilms are bacterial communities adhered to a surface with a self-made extracellular polymeric substance that surrounds resident bacteria. In contrast to planktonic bacteria, bacteria in a biofilm are in an adherent, dormant state and are insensitive to most antibiotics. In addition, bacteria in a biofilm are protected from phagocytic cells of the immune system. Therefore, complete surgical removal and replacement of the prosthetic implant is often necessary to treat this type of infections. Neutrophils play a crucial role in clearing bacterial pathogens. They recognize planktonic bacteria via immunoglobulin (Ig) and complement opsonisation. In this project, we aim to evaluate the role of IgG and complement in the recognition and clearance of staphylococcal biofilms by human neutrophils. Furthermore, we evaluate if monoclonal antibodies (mAbs) targeting biofilm structures can enhance recognition and clearance of staphylococcal biofilms by the human immune system.”

Method

“We produced a set of 20 recombinant mAbs specific for staphylococcal antigens. Using flow cytometry and ELISA-based methods we determined the binding of these mAbs to planktonic staphylococci and in vitro staphylococcal biofilms. Following incubation with IgG/IgM depleted human serum we determined whether mAbs can react with the human complement system after binding to biofilm. Confocal microscopy was used to visualize the location of antibody binding in the biofilm 3D structure.”