Antigen-Specific Cytolysis by Neutrophils and NK Cells Expressing Chimeric Immune Receptors Bearing ζ or γ Signaling Domains

TCR- and IgG-binding Fc receptors (FcγR) mediate a variety of critical biologic activities including cytolysis via the structurally related ζ- and γ-chains. In previous studies, we have described chimeric immune receptors (CIR) in which the ligand-binding domain of a heterologous receptor or Ab is fused directly to the cytoplasmic domain of the TCR ζ-chain. Such ζ-CIRs efficiently trigger cytotoxic function of both T and NK cells in a target-specific manner. In this report, we compared the ability of both ζ- and γ-CIRs to activate the cytolytic function of two distinct classes of FcγR-bearing effectors, NK cells and neutrophils. Mature neutrophils expressing ζ- and γ-CIR were generated in vivo from murine hemopoietic stem cells following transplantation of syngeneic mice with retrovirally transduced bone marrow or in vitro from transduced human CD34+ progenitors following differentiation. Both ζ- and γ-based CIRs were capable of activating target-specific cytolysis by both NK cells and neutrophils, although the ζ-CIR was consistently more efficient. The experimental approach described is a powerful one with which to study the role of nonlymphoid effector cells in the host immune system and permits the rational design of immunotherapeutic strategies that rely on harnessing multiple immune cell functions via CIR-modified hemopoietic stem cells or progenitors.