When T-Cells are activated they release cytokines (yes, that cytokine), which trigger additional T-Cells to be made, which then release even more cytokines. One type of T-cells that are created are called cytotoxic T-cells. Cytotoxic T-cells are the cells that are able to roam the body and mercy kill infected cells who are chemically calling out to be killed and ideally to stop the increased production of viruses like COVID-19.