Differential inhibition of HVEM/CD160 binding with benchmark tool antibodies. TRF assay measuring the potency of different antibodies to inhibit the binding of recombinant human HVEM-Fc chimera to CD160+ CHO-K1 cells. A) CD160 monoclonal antibodies inhibit binding of HVEM-Fc to both CD160-GPI and CD160-TM isoforms. B) Polyclonal HVEM (left panel) and monoclonal HVEM (right panel) antibodies both enhance binding of HVEM-Fc to CD160-TM isoform. The polyclonal anti-HVEM inhibits HVEM-Fc binding to CD160-GPI (left panel). Antibody concentrations are plotted on the X axis whereas, the calculated percentage of inhibition of binding is plotted on the Y axis. Matched isotype control antibody for each individual antibody candidate was also used in the assay (empty circles and squares). CTL = control, mAb = monoclonal antibody, pAb = polyclonal antibody.