Case Studies

Case Study C5aR-Twist Bioscience

The C5a anaphylatoxin chemotactic receptor 1 (C5aR, also known as CD88) belongs to the rhodopsin family of GPCRs and has been a topic of interest in the last decades due to its relevance in several inflammatory pathologies, such as asthma, arthritis, sepsis, and more recently Alzheimer’s disease and cancer. Even though the interaction between C5a and C5aR is of high therapeutic value, their molecular binding mechanism remains elusive, and several efforts are ongoing to find new drugs acting on C5aR.

One promising way of speeding up the identification of potential drugs acting on C5aR (being small molecules or biologicals as antibodies), is using fluorescence-based assays, like flow cytometry or fluorescence polarization. This kind of assays can be adapted to medium and high throughput screening with a read out easy to scale up. However, there is a major bottleneck in this approach: the availability of optimal fluorescent probes.

 In this case study we describe how, following the demand of the US-based biotech company Twist Bioscience (, we applied Celtarys technology to the development of two new fluorescent ligands for C5AR, opening the way to the use of fluorescence-based assays to study this promising target.

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