According to Schneck, to enhance this natural process, several laboratories, including his own, have made various types of "artificial APCs" tiny inanimate spheres "decorated" with pieces of tumor proteins and danger signals. These are then often used in immunotherapy techniques in which immune cells are collected from a cancer patient and mixed with the artificial APCs. When they interact with the patient's T-cells, the T-cells are activated, learn to recognize the tumor cell proteins and multiply over the course of several days. The immune cells can then be transferred back into the patient to seek out and kill cancer cells.
The cell-based technique has had only limited success and involves risks due to growing the cells outside the body, Green says. These downsides sparked interest in the team to improve the technique by making biodegradable artificial APCs that could be administered directly into a potential patient and that would better mimic the interactions of natural APCs with T-cells. "When immune cells in the body come in contact, they're not doing so like two billiard balls that just touch ever so slightly," explains Green. "Contact between two cells involves a significant overlapping surface area. We thought that if we could flatten the particles, they might mimic this interaction better than spheres and activate the T-cells more effectively."
To flatten the particles, two M.D./Ph.D. students, Joel Sunshine and Karlo Perica, figured out how to embed a regular batch of spherical particles in a thin layer of a glue-like compound. When they heated the resulting sheet of particles, it stretched like taffy, turning the round spheres into tiny football shapes. Once cooled, the film could be dissolved to free each of the microscopic particles that could then be outfitted with the tumor proteins and danger signals. When they compared typical spherical and football-shaped particles both coated with tumor proteins and danger signals at equ
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Johns Hopkins Medicine