Bi-specific antibodies crosslink and redirect CD8+ T cells to kill cytomegalovirus-infected cells

CD8+ T lymphocytes (CTLs) are crucial for the control of cytomegalovirus (CMV) infection, as shown in studies of adoptive transfer of ex vivo expanded autologous CMV-specific cells, but harnessing this approach in immunocompromised hosts with disseminated infection has not been feasible. The use of chimeric antigen receptors has been proposed, but faces similar logistical challenges. Here we present T cell redirecting bi-specific antibodies (TRBAs) that crosslink CD3-epsilon on CTLs to the gH protein on CMV-infected cells. Two designs are evaluated, including a version where a single chain antibody is appended to the C-terminus of the heavy chain of a normal antibody, and a version where both light and heavy chains have two tandem variable regions in a cross-over ordered design. Both versions of these antibodies are demonstrated to bind both antigens and mediate specific clearance of infected cells with the release of interferon-gamma when added to CTLs and CMV-infected cells.