T-Cell-Activating Lipid Nanoparticles for Rapid Engineering of CAR T Cells

A method to streamline the process of generating chimeric antigen receptor (CAR) T cells for therapeutic applications.
Problem:
CAR T cell therapy has demonstrated clinical success in treating various forms of cancer. With more CAR T cell therapies projected to gain regulatory approval, manufacturing becomes increasingly important in the face of this rising demand. Currently, engineering of CAR T cells ex vivo is a lengthy and complicated process that involves leukapheresis, artificial T cell activation, and CAR construct delivery. In particular, artificial T cell activation generally employs magnetic beads (Dynabeads®) conjugated with CD3 and CD28 antibodies to mimic the natural process mediated by antigen presenting cells (APCs). While effective, a downside of this method is the need to remove the magnetic beads prior to clinical administration of the cell product. This cumbersome process can hamper cell yields and augment manufacturing time and costs.
Solution:
Metzloff et al. developed an mRNA lipid nanoparticle (aLNP) that is capable of activating T cells and delivering a CAR-encoding mRNA all in one step.
Technology:
To enable concurrent T cell activation and mRNA delivery, Metzloff et al. incorporated APC mimetics onto the LNP delivery vehicle. Assembled using the conventional four lipid components, the aLNPs contain fragments of CD3 and CD28 antibodies conjugated to one of the lipid components. Attachment of these T-cell-activating moieties confers the LNPs an added function of T cell activation in addition to their canonical role of delivering mRNA. This provides a means to compress the current multi-step workflow of CAR T cell engineering into one single step.
Advantages:

Simplifies the complex CAR T cell engineering process by enabling simultaneous T cell activation and CAR construct delivery
Improves cell yields and reduces engineering time and costs
Improves mRNA delivery to T cells by 6.5-fold compared to the standard sequential method using Dynabeads® followed by regular LNPs
CAR T cells generated using aLNPs retain potent cancer cell killing ability
The tunable ratio of CD3 to CD28 antibodies on the aLNP surface allows for control over T cell differentiation, memory formation, and construct expression
Modular platform allows for delivery of other types of cargoes (siRNA, DNA, proteins, etc.) to T cells for diverse immunotherapy applications
Can further employ other proteins or antibody fragments (other than those targeting CD3 and CD28) to enhance or change the cell-modulating properties of aLNPs

Stage of Development:

Concept
Proof of Concept

(A) Schematic of the old multi-step workflow of generating CAR T cells ex vivo vs. the new one-step workflow using aLNPs. (B) aLNPs improved the efficiency of mRNA transfection into primary human T cells when compared to the sequential Dynabead®-mediated approach. (C) CAR T cells generated using aLNPs retained equally potent cancer-killing capability, as demonstrated via a co-culture assay with luc+ Nalm6 acute lymphoblastic leukemia cells.
Intellectual Property: