Th2 cells, or T helper type 2 cells, are a subset of T cells that play a crucial role in the immune system. They are primarily involved in the response to parasites and allergens. Th2 cells produce specific cytokines, such as IL-4, IL-5, and IL-13, which help activate other immune cells, including B cells that produce antibodies. These cytokines also promote the differentiation of B cells into plasma cells, enhancing the production of IgE antibodies. Th2 cells are essential for orchestrating the immune response against extracellular pathogens and are implicated in allergic reactions and asthma when their activity is dysregulated.