Stephanie, G. | Search bioRxiv

bioRxiv2022

Lipid-polymer hybrid nanoparticles utilize B cells and dendritic cells to elicit distinct antigen-specific CD4+ and CD8+ T cell responses

Antigen presenting cells (APCs) have been extensively studied for treating cancers and autoimmune diseases. Dendritic cells (DCs) are potent APCs that uptake and present antigens (Ags) to activate immunity or tolerance. Despite their active use in cellular immunotherapies, DCs face several challenges that hinder clinical translation, such as inability to control Ag dosing for tuning immune responses and low abundance in peripheral blood. B cells are a potential alternative to DCs, but their poor non-specific Ag uptake capabilities compromise controllable priming of T cells. We developed phospholipid-conjugated Ags (L-Ags) and lipid-polymer hybrid nanoparticles (L/P-Ag NPs) as Ag delivery platforms to expand the range of accessible APCs for use in priming CD4+ and CD8+ T cells. These delivery platforms were evaluated using DCs, CD40-activated B cells, and resting B cells as a diverse set of APCs to understand the impact of various Ag delivery mechanisms for generation of Ag-specific T cell responses. L-Ag delivery (termed depoting) of MHC class I and II-restricted Ags successfully loaded all APC types in a tunable manner and primed both Ag-specific CD8+ and CD4+ T cells, respectively. Incorporating L-Ags and polymer-conjugated Ags (P-Ag) into NPs can direct Ags to different uptake pathways to engineer the dynamics of presentation and shape T cell responses. DCs were capable of processing and presenting Ag delivered from both L- and P-Ag NPs yet B cells could only utilize Ag delivered from L-Ag NPs. Multivariate analysis of cytokines secreted from APC:T cell co-cultures indicated that L-Ag NPs primed different T cell responses than P-Ag NPs. Altogether, we show that L-Ags and P-Ags can be rationally paired within a single NP to leverage distinct delivery mechanisms to access multiple Ag processing pathways in two APC types, offering a modular delivery platform for engineering immunotherapies.

bioengineering↗

bioRxiv2019

Lipid-mediated insertion of Toll-like receptor (TLR) ligands for facile immune cell engineering

Cell-based immunotherapies have tremendous potential to treat many diseases, such as activating immunity in cancer or suppressing it in autoimmune diseases. Most cell-based cancer immunotherapies in the clinic provide adjuvant signals through genetic engineering to enhance T cell functions. However, genetically encoded signals have minimal control over dosing and persist for the life of a cell lineage. These properties make it difficult to balance increasing therapeutic efficacy with reducing toxicities. Here, we demonstrated the potential of phospholipid-coupled ligands as a non-genetic system for immune cell engineering. This system provides simple, controlled, non-genetic adjuvant delivery to immune cells via lipid-mediated insertion into plasma membranes. Lipid-mediated insertion (depoting) successfully delivered Toll-like receptor (TLR) ligands intracellularly and onto cell surfaces of diverse immune cells. These ligands depoted into immune cells in a dose-controlled fashion and did not compete during multiplex pairwise loading. Immune cell activation could be enhanced by autocrine and paracrine mechanisms depending on the biology of the TLR ligand tested. We determined that depoted ligands can functionally persist on plasma membranes for up to four days in naive and activated T cells, enhancing their activation, proliferation, and skewing cytokine secretion. Depoted ligands provide a persistent yet non-permanent adjuvant signal to immune cells that may minimize the intensity and duration of toxicities compared to permanent genetic delivery. Altogether, these findings demonstrate potential for lipid-mediated insertion (depoting) as a universal cell engineering approach with unique, complementary advantages to other cell engineering methods.

immunology↗