1. Antibody-antibiotic conjugate targeted therapy for orthopedic implant-associated intracellular S. aureus infections.
- Author
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Qin, Leilei, Hu, Ning, Zhang, Yanhao, Yang, Jianye, Zhao, Liqun, Zhang, Xiaokai, Yang, Yun, Zhang, Jinyong, Zou, Yinshuang, Wei, Keyu, Zhao, Chen, Li, Yujian, Zeng, Hao, Huang, Wei, and Zou, Quanming
- Abstract
Scheme illustration of Antibody-antibiotic conjugates (AAC) target S. aureus and mediate endocytosis to kill bacteria after entry into the cell. The proposed mechanism suggests that S. aureus-AAC complex mediates endocytosis through the antibody Fcγ receptor, and cathepsin cleaves the intracellular AAC-linker to release vancomycin. Subsequently, vancomycin completed the elimination of S. aureus in the cell. [Display omitted] • S. aureus exists in the synovial fluid of patients in the form of a "Trojan horse", avoiding antibiotic treatment and mediating infection recurrence. • The main host cell types of MRSA in implant infection in mice are macrophages, osteoclasts, synoviocytes and osteoblasts. • The modified SpA antibody (M0662) from a clinical strain has a high affinity with SpA surface antigen of S. aureus (KD < 10
-3 nM). • AAC captures extracellular S. aureus and acts as a "biological bomb" to rapidly eliminate S. aureus in the cell. • Application of AACs in the implant infection model significantly improved the bactericidal effect of vancomycin and blocked bacterial biofilm formation. Treating orthopedic implant-associated infections, especially those caused by Staphylococcus aureus (S. aureus) , remains a significant challenge. S. aureus has the ability to invade host cells, enabling it to evade both antibiotics and immune responses during infection, which may result in clinical treatment failures. Therefore, it is critical to identify the host cell type of implant-associated intracellular S. aureus infections and to develop a strategy for highly targeted delivery of antibiotics to the host cells. Introduced an antibody-antibiotic conjugate (AAC) for the targeted elimination of intracellular S. aureus. The AAC comprises of a human monoclonal antibody (M0662) directly recognizes the surface antigen of S. aureus , Staphylococcus protein A, which is conjugated with vancomycin through cathepsin-sensitive linkers that are cleavable in the proteolytic environment of the intracellular phagolysosome. AAC, vancomycin and vancomycin combined with AAC were used in vitro intracellular infection and mice implant infection models. We then tested the effect of AAC in vivo and in vivo by fluorescence imaging, in vivo imaging, bacterial quantitative analysis and bacterial biofilm imaging. In vitro, it was observed that AAC captured extracellular S. aureus and co-entered the cells, and subsequently released vancomycin to induce rapid elimination of intracellular S. aureus. In the implant infection model, AAC significantly improved the bactericidal effect of vancomycin. Scanning electron microscopy showed that the application of AAC effectively blocked the formation of bacterial biofilm. Further histochemical and micro-CT analysis showed AAC significantly reduced the level of bone marrow density (BMD) and bone volume fraction (BV/TV) reduction caused by bacterial infection in the distal femur of mice compared to vancomycin treatment alone. The application of AAC in an implant infection model showed that it significantly improved the bactericidal effects of vancomycin and effectively blocked the formation of bacterial biofilms, without apparent toxicity to the host. [ABSTRACT FROM AUTHOR]- Published
- 2024
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