What is cellular immunotherapy?

Cellular immunotherapy modifies a person's immune cells (e.g., through genetic engineering or modulating protein expression profile) before reintroducing them back into the body for therapeutic purposes. For example, T-cells can be isolated directly from a patient and then modified in a research laboratory to express receptors targeting cancer cell-specific antigens. These modified T-cells are then allowed to multiply in incubators, after which they are reintroduced in large numbers back into the patient to seek out cancer cells for immune-mediated elimination.2

Reference:
1. Z. Tao, et al., "Cellular immunotherapy of cancer: an overview and future directions," Immunotherapy 9(7):589-606, 2017.