In Vivo Imaging of Local Inflammation: Monitoring LPS-Induced CD80/CD86 Upregulation by PET.
Mol Imaging Biol 2020;
23:196-207. [PMID:
32989622 PMCID:
PMC7910267 DOI:
10.1007/s11307-020-01543-3]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 08/11/2020] [Accepted: 09/10/2020] [Indexed: 12/24/2022]
Abstract
Purpose
The co-stimulatory molecules CD80 and CD86 are upregulated on activated antigen-presenting cells (APC). We investigated whether local APC activation, induced by subcutaneous (s.c.) inoculation of lipopolysaccharides (LPS), can be imaged by positron emission tomography (PET) with CD80/CD86-targeting 64Cu-labelled abatacept.
Procedures
Mice were inoculated s.c. with extracellular-matrix gel containing either LPS or vehicle (PBS). Immune cell populations were analysed by flow cytometry and marker expression by RT-qPCR. 64Cu-NODAGA-abatacept distribution was analysed using PET/CT and ex vivo biodistribution.
Results
The number of CD80+ and CD86+ immune cells at the LPS inoculation site significantly increased a few days after inoculation. CD68 and CD86 expression were higher at the LPS than the PBS inoculation site, and CD80 was only increased at the LPS inoculation site. CTLA-4 was highest 10 days after LPS inoculation, when CD80/CD86 decreased again. A few days after inoculation, 64Cu-NODAGA-abatacept distribution to the inoculation site was significantly higher for LPS than PBS (4.2-fold). Co-administration of unlabelled abatacept or human immunoglobulin reduced tracer uptake. The latter reduced the number of CD86+ immune cells at the LPS inoculation site.
Conclusions
CD80 and CD86 are upregulated in an LPS-induced local inflammation, indicating invasion of activated APCs. 64Cu-NODAGA-abatacept PET allowed following APC activation over time.
Electronic supplementary material
The online version of this article (10.1007/s11307-020-01543-3) contains supplementary material, which is available to authorized users.
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