Authors:

Quinte Robinson

Date Created:

Not specified

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Professor:

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About Paper:

Cell-based immunotherapies, especially Chimeric Antigen Receptor (CAR) T cells, are promising cancer treatments that redirect T cell cytotoxicity to eliminate tumors via secretion of lytic molecules such as perforins and granzymes (degranulation). While highly effective against blood cancers, their success in solid tumors is limited, partly due to on- target, off-tumor toxicity when CAR T cells attack healthy cells with low levels of the same antigens. We have shown CAR T cells can be triggered by single-molecule events, suggesting a mechanism for aberrant activation. However, the precise determinants of when, where, and how much degranulation occurs remain unclear. We hypothesize that cellular machinery regulating degranulation also sets activation thresholds. Actin remodeling integrates upstream signaling required for T cell activation, with local actin clearance necessary for effective degranulation. By systematically varying tumor antigen density, we will investigate how signaling strength drives actin remodeling and lytic granule mobilization. T cells will interact with model surfaces presenting defined antigen densities, and membrane-proximal events will be visualized using total internal reflection fluorescence (TIRF) microscopy. Actin and lytic granules will be fluorescently labeled with FastAct and LysoTracker, respectively, to simultaneously monitor remodeling and granule dynamics. We aim to define where the membrane is licensed for degranulation and what governs granule fusion, informing refinements to CAR T cell therapies that improve tumor killing while reducing healthy tissue damage. Keywords: Cancer; Biophysics; Immunology

Source:

Purdue University / 2025

Topics:

No topics listed

Co-authors:

Quinte Robinson