Final answer:
Th1 cells indirectly support the killing of cells by secreting cytokines that enhance the activity of cytotoxic T cells and macrophages. Th1 cells play an b) indirect, immunosuppressive role rather than being directly cytotoxic.
Step-by-step explanation:
Th1 cells play a crucial role in the immune system's response to intracellular pathogens. They are not directly involved in killing cells in the way cytotoxic T cells (Tc cells) are, but rather they perform a supportive role. TH1 cells secrete cytokines that stimulate and enhance the activity of effector cells such as cytotoxic T cells and macrophages which in turn kill infected cells or pathogens. Therefore, based on the options provided, Th1 cells play a B) Indirect, immunosuppressive role in killing cells. They indirectly facilitate the destruction of infected cells by boosting the cytotoxic functions of other immune cells, but they are not themselves cytotoxic.