What is the primary purpose of using proinflammatory cytokines like interleukin-12 in the immune response?

The primary purpose of using proinflammatory cytokines such as interleukin-12 is to stimulate T lymphocyte activity. Interleukin-12 plays a critical role in the immune system by promoting the differentiation of naïve T cells into Th1 cells, which are essential for the cellular immune response. These Th1 cells are important for activating cytotoxic T cells and enhancing the ability to combat intracellular pathogens, including viruses and certain bacteria.

Additionally, interleukin-12 can increase the production of interferon-gamma (IFN-γ) from T cells and natural killer (NK) cells, further amplifying the immune response toward those pathogens. This cytokine not only influences T lymphocyte activity but also has effects on enhancing the immune system's overall ability to fight infections.

While enhancing granulocyte function and supporting macrophage apoptosis are important in the immune response, these mechanisms are not the primary focus of interleukin-12's action. Instead, its primary role is closely aligned with the stimulation of T lymphocyte activity, which is fundamental to immune defense. The decrease of leukocyte production is contrary to the goal of mounting an effective immune response.