Engineering Erythrocytes for Immune Tolerance via CellSqueeze® Technology

Engineering Erythrocytes for Immune Tolerance via CellSqueeze® Technology

Derrick P. McCarthy¹, Maria E. Trujillo¹, Amritha Ramakrishnan¹, Lindsay J. Moore¹, Alfonso V. Suarez¹, Finola E. Moore¹, Howard Bernstein¹, Armon Sharei¹

SQZ Biotechnologies, 134 Coolidge Avenue, Watertown, Massachussetts, 02472, United States.

Current treatment of autoimmunity typically relies on the use of broadly immunosuppressive agents that increase the risk of adverse events in the patient, such as cancer and opportunistic infections. The induction of peripheral tolerance by antigen-specific immunotherapy has the potential to alleviate these risks while eliminating the undesirable immune response to self-antigens. Building on the well-defined erythrocyte literature, we and others have shown that the use of red blood cells (RBCs) as a platform for delivering antigens can exert tolerogenic effects when the antigens are presented in the context of eryptosis, a mechanism of RBC clearance. Using the microfluidic CellSqueeze® (SQZ) technology, we obtain highly delivered, pro-eryptotic RBCs as a platform for inducing tolerance. In this approach, cells are passed through constricting channels, thereby inducing temporary permeation of the cell membrane that allows diffusion of molecules into the cell before the membrane reseals. Here, we demonstrate that these highly -delivered RBCs are rapidly cleared from circulation by splenic and liver-resident macrophages and induce a state of functional hyporesponsiveness in T cells. The administration of ovalbumin-SQZ’d RBCs led to a reduction in OT-I T cell proliferation and cytokine production in a model of ovalbumin immunization. In a model of BDC2.5 T cell mediated transfer induced diabetes, RBCs SQZ’d with the 1040-p31 peptide mimetope protected recipients from the onset of hyperglycemia. Finally, RBCs SQZ’d with a model drug also led to potent inhibition of anti-drug antibody (ADA) responses and preserved drug levels in circulation. SQZ’d RBCs are an efficacious and versatile method for exploiting natural tolerogenic mechanisms in the treatment of T cell-mediated autoimmune inflammation and ADA responses.