P09.03 Loading of T cells with superparamagnetic iron oxide nanoparticles gives them magnetic controllability while retaining antigen-specific effector functions

April, 04, 2024 | Select Oncology Journal Articles


The composition of the tumor microenvironment in solid tumors is of crucial importance for the prognosis and clinical outcome of patients with solid cancers (1). Infiltration of CD8+ T cells into the tumor can improve the prognosis and treatment options of patients. Adoptive T cell therapy is intended to increase the number of CD8+ T cells in the tumor. However, only a fraction of cancer patients benefit from this option, partially because the T cells do not effectively reach the tumor (2). We developed citrate-coated superparamagnetic iron oxide nanoparticles (SPIONs) for the loading of T cells to make them magnetically controllable (3,4). After intra-arterial application and magnetic enrichment in the tumor region, SPION-loaded T cells must pass through the vessel wall to reach the tumor and they must retain antigen-specific effector functions to fight the tumor. This study investigated the effects of SPION loading on primary human T cells, particularly on antigen-specific effector functions and their cellular migration capacity (5).

Materials and Methods

T cells were freshly isolated from human whole blood and subsequently loaded with SPIONs for 4 h. Unloaded T cells served as controls. Using a Boyden-Chamber-based assay, we acquired information about the ability of T cell to migrate towards a CXCL12-gradient. Furthermore, the tethering and attachment of T cells on an endothelial cell monolayer was investigated by fluorescence microscopy. The deformability upon SPION-loading was investigated using Real-Time Deformability Cytometry (RT-DC). Antigen-specific effector functions were examined after stimulation via an introduced exogenous T cell receptor (TCR) specific for the melanoma antigen MelanA or the endogenous TCR specific for the cytomegalovirus antigen pp65.


SPION-loading had no effect on the attachment of T cells to an endothelial monolayer, however, the chemotactic migration was reduced by SPIONs, which was cancelled out by magnetic attraction. RT-DC ruled out stiffening of the cells due to nanoparticle loading, which is important for squeezing through the vessel walls during transmigration. Lastly, we observed no alterations in antigen-specific effector functions regarding proliferation, expression of activation markers, cytokine secretion, or tumor cell killing after antigen-specific activation mediated by endo- or exogenous TCRs.


In sum, we showed that SPION loading did not impair cellular mechanics or antigen-specific effector functions. With regard to cell transmigration, possible negative effects of SPION-loading on the T cells were compensated by magnetic attraction. These results underline the potential of SPIONs for the enrichment of T cells in the tissue of solid tumors through magnetic attraction.


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  • L.R. Carnell: None. S. Knorr: None. F. Pfister: None. J. Dörrie: None. N. Schaft: None. C. Alexiou: None. C. Janko: None.

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