Measure Potency and Stability of FcγRIIb Crosslinking-Dependent and -Independent Agonist Antibodies，Use with ICOS and CD28 bioassays to provide activation of TCR/CD3 complex on effector cells and crosslink antibodies，Measure FcγRIIb crosslinking dependence of agonist antibodies that stimulate T cell activation，Mechanism-of-action-based