Memory T cells are a type of immune cell that play a crucial role in the adaptive immune response. These cells are formed after an initial exposure to a pathogen, such as a virus or bacterium, and are responsible for providing long-lasting immunity against that specific pathogen. Memory T cells are capable of quickly recognizing and responding to the pathogen upon re-exposure, leading to a more rapid and robust immune response. This memory allows the immune system to mount a more effective defense against previously encountered pathogens, providing protection against future infections. Memory T cells are a key component of immunological memory and are critical for maintaining immune protection over time.