Delayed-type hypersensitivity (DTH) in vivo assay represents a relatively quick and useful approach for evaluating the efficacy of potential immunomodulatory or immunosuppressive compounds. By challenging the cell-mediated immune response, you obtain valuable information such as whether your lead immunomodulatory compound can reduce DTH in mice.  

Hypersensitivity reactions can be evaluated based on the delivery of the antigen by either injection into the skin, skin absorption following topical administration or via the gut (DSS-induced colitis). In this newsletter, we present data from in-house validated DTH induced by injection.  

On day 0, mice were sensitized by a subcutaneous injection with KLH/CFA/IFA emulsion in the tail base. Six days later, following baseline measurements, mice were challenged with a KLH injection into one ear and PBS injection into the other ear as a within-subject control. Treatment with an anti-inflammatory drug was used as a positive control for KLH hypersensitivity.  

In line, we observed clear increases in ear thickness on the days after KLH challenge compared to baseline (day 6). Moreover, ear thickness of PBS control ears and KLH-injected ears of Rapidexon-treated animals showed reduced swelling throughout the whole study duration, confirming the suitability of this assay.   

The readouts performed in this assay can be tailored, using your mouse model of choice:  

• Localised ear swelling measurement 
• Blood and/or serum collection for PK/PD profiling and/or immune cell profiling via flow cytometry  
• Histopathological evaluation using either classical H&E stains and/or IHC  

All efficacy studies can be complemented with histopathology readouts with in-house expert pathologist evaluation. As an example, the H&E-stained digitalized whole-slide images below show (A) infiltration of immune cells consisting of mainly lymphocyte in the dermis. (B) Non-inflamed dermis.  

In addition to performing PK/PD studies and analyses, InnoSer can help you perform safety pharmacology analyses, ensuring your compound’s safety.