CD19 CAR FMC63 Idiotype Antibody, PE, REAfinity™，130-127-342，美天旎

The CD19 CAR FMC63 Idiotype Antibody, REAfinity™ has been developed for the detection of genetically modified T cells that are engineered to express a chimeric antigen receptor (CAR) comprising a single chain variable fragment (scFv), which derives from the mouse anti-human CD19 antibody clone FMC63. The CD19 CAR FMC63 Idiotype Antibodies, REA1297 and REA1298, are anti-idiotype antibodies that recognize the FMC63 scFv and feature a specifically mutated human IgG1 Fc region. The mutated human IgG1 Fc region of the CD19 CAR FMC63 Idiotype Antibody abolishes its binding to Fcγ receptors, which allows for background-free analysis and eliminates the need for additional blocking steps, such as using a FcR blocking reagent.

FMC63 scFv

Technical specifications

To compare the epitope specificity of the CD19 CAR FMC63 Idiotype Antibodies REA1297 and REA1298, competition assays with both clones and CD19 Fc fusion protein (CD19 Fc) were performed. CD19 CAR T cells were incubated with an excess of unconjugated CD19 Fc, followed by staining with fluorochrome-conjugated REA1297 or REA1298. Based on the fluorescence signal obtained, the clones were identified as recognizing overlapping or different epitopes on the FMC63 derived scFv. CD19 Fc prevented staining with REA1297, whereas CD19 Fc and REA1298 staining did not interfere with each other. This demonstrates that REA1297 reacts with a similar site as CD19, but REA1298 binds to a different part of FMC63 scFv (outside the paratope), and hence, does not compete for the CD19 antigen-binding domain.