CD4+ T cells are a type of white blood cell that play a crucial role in the immune system. They are often referred to as "helper T cells" because they help activate and direct other immune cells, such as B cells and cytotoxic T cells, to respond to infections and diseases. These cells recognize specific antigens presented by antigen-presenting cells and release signaling molecules called cytokines. This process enhances the immune response, enabling the body to effectively fight off pathogens like viruses and bacteria. A healthy population of CD4+ T cells is essential for maintaining a strong immune defense.