Binding characteristics of MK-5890 and varlilumab
| Antibody | Target | Affinity by surface plasmon resonance (Biacore) | Flow cytometry EC50±SD (nM) | CHO-ELISA EC50±SD (nM) | |||
| ka (M-1s-1) | kd (s-1) | KD ± SD (nM) | CD8+ T | CD4+ T | |||
| MK-5890 | Human CD27 | 2.2×105 | 1.1×10-3 | 5.1±0.1 | 0.30±0.07 | 0.32±0.07 | 0.072±0.013 |
| Rhesus CD27 | 2.3×105 | 1.0×10-3 | 4.3±0.2 | 0.22±0.08 | 0.17±0.07 | 0.054±0.005 | |
| varlilumab | Human CD27 | 1.9×105 | 1.2×10-4 | 0.63±0.02 | 1.30±0.60 | 1.54±0.80 | 0.325±0.068 |
| Rhesus CD27 | 2.3×105 | 2.2×10-4 | 0.97±0.01 | 1.92±3.81 | 1.58±0.29 | 0.193±0.063 | |
Binding affinity of anti-CD27 Abs was determined using Biacore instrumentation with human CD27-IgG and rhesus monkey CD27-IgG fusion proteins captured on the chip. Binding of anti-CD27 Abs to human and rhesus monkey peripheral blood mononuclear T cells was determined based on mean fluorescence intensity using flow cytometry. Binding of anti-CD27 Abs to CHO cells expressing human or rhesus monkey CD27 was assessed using an ELISA. ka=association rate constant; kd=dissociation rate constant; KD=equilibrium dissociation constant; M=molar; nM=nanomolar; s=seconds; SD=SD deviation. CHO=Chinese hamster ovary, EC50=half-maximal effective concentration(s)