Final answer:
It is True that cytokines are produced by antigen-presenting cells (APCs) that present to CD4+ Th1 helper T cells. Both APCs and CD4+ T cells release cytokines, which play a crucial role in immune response regulation and activation of other immune system components.
Step-by-step explanation:
The statement that cytokines are produced by antigen-presenting cells (APCs) which present to CD4+ Th1 helper T cells is True. During the immune response, when a CD4+ helper T cell binds to an MHC II-antigen complex on an antigen-presenting cell, both the APC and the T cell secrete cytokines. These cytokines have various roles, including the activation of other immune cells such as B cells for antibody production, recruitment and activation of macrophages, and activation of cytotoxic killer T cells.
Helper T cells bearing the CD4 molecule function by secreting cytokines to enhance immune responses. Specifically, they can differentiate into different subclasses, such as Th1 or Th2, with Th1 cells being particularly effective in cell-mediated responses against intracellular pathogens and Th2 cells being associated with humoral immunity and defense against extracellular pathogens.
Thus, the production of cytokines by APCs that are presenting antigens to CD4+ Th1 cells is a crucial step in the activation and direction of the immune response.