A novel and efficient method to induce allospecific CD8⁺ memory T lymphocytes

The aim of the current study was to establish a simple method for effectively inducing memory T lymphocytes by the intraperitoneal injection of spleen lymphocytes into mice. In total, 75 mice were divided into the following groups: an injection group administered three doses of spleen lymphocytes (1 × 10 6 , 5 × 10 6 , and 1 × 10 7 cells), a transplantation group in which a 0.25‐cm 2 skin section from C57BL/6 mice was transplanted onto the back of the recipient, and a control group in which an equal volume of phosphate‐buffered saline was injected. At 1, 2, or 3 months following transplantation, the following parameters were evaluated: quantity of T lymphocytes, percentage of cluster of differentiation 8 + (CD8 + ) memory T cells, and proliferation index of purified CD8 + memory T cells. No significant differences among groups were detected at 1 month ( p > .05). However, the injection group administered 1 × 10 6 cells exhibited the highest proportion of CD8 + memory T cells among all groups at 2 months, and the proportions of CD8 + T cells were higher in the three injection groups than in the skin transplantation and control groups at 3 months. The proportions of memory T cells were higher in the injection groups administered 5 × 10 6 or 1 × 10 7 cells than in the skin transplantation and control groups at 3 months. The newly established method effectively induces memory T lymphocytes via the intraperitoneal injection of spleen lymphocytes in vivo and has potential applications in the field of immunotherapy.