T-Cell B-Cell Communication When a pathogen is detected, a cascade of reactions occurs and part of that process involves T-Cells activating B-Cells. T cells and B cells are two types of immune cells that work together to protect the body against harmful invaders like viruses and bacteria. T cells are activated when they recognize antigens, which are foreign substances in the body, on the surface of infected or abnormal cells. Once activated, T cells release signaling molecules that attract and a