Abstract
Therapeutic antibodies can engage innate (NK) and adaptive (T) immune cells to eliminate pathogenic or malignant cells. Activated NK or T cells exert cytotoxic effects dependent upon direct cell-cell contact and subsequent formation of immunological synapses (IS) with target cells. Therefore, understanding antibody-mediated cell-cell interactions is crucial to optimizing antibody pharmacology and efficacy across all therapeutic areas. To date, most investigations around antibody-mediated cell-cell interactions have primarily focused on molecular-scale interactions. In this study, we developed a biosensor system to evaluate direct cell-cell contact and interactions and the formation of IS at the cell population level. In this biosensor system, two structural complementary luciferase units (SmBit and LgBit) were respectively expressed on immune effector and target cell membranes with optimized spacer lengths. Upon cell-cell contact, two subunits come together to form active NanoLuc, generating a luminescent signal for longitudinal monitoring. The selectivity of the system were optimized by adjusting the spacer lengths to assure the signal is from stable cell-cell interactions with minimal interference from nonspecific and transient intercellular contact. This system was then applied to longitudinally quantify cell-cell interactions between NK and target cells induced by an anti-CD20 antibody (rituximab) and between T and target cells induced by a bispecific (anti-CD3/CD19) T cell engaging antibody (blinatumomab) in a three-dimensional cell culture system. This biosensor system shows promise for monitoring cell-cell interactions in physiologically relevant environments and provides insights into the environmental factors that impede cell-cell interaction and antibody efficacy.
Competing Interest Statement
The authors have declared no competing interest.
