What function do T helper (Th, CD4+) cells serve in the immune system?

T helper (Th, CD4+) cells play a crucial role in the immune system primarily by stimulating immune responses. These cells do not directly attack pathogens; instead, they enhance the immune response by secreting cytokines that activate and direct other immune cells. This includes activating B cells to produce antibodies, helping cytotoxic T cells to kill infected cells, and stimulating macrophages to engulf and destroy pathogens.

The function of T helper cells is integral to orchestrating the overall immune response, ensuring that it is appropriately targeted and effective against invaders such as viruses and bacteria. By facilitating communication and coordination among various components of the immune system, T helper cells help to ensure a robust and efficient immune response, which is essential for protecting the body against infections.