What are the differences between naïve and memory T cells?

Naïve T Cells

Naïve T cells originate in the bone marrow and mature in the thymus. They are an essential component of the immune system. Naïve T cells are fighter cells and are actively involved in fighting off pathogens and infections. They are quiescent and non-dividing. 

Main functions of naïve T cells include:

• Recognizing matching antigens and initiating an immune response

• Eliminating new and unrecognized antigens that the immune system has never encountered before

Memory T Cells

Memory T Cells originate in the lymph nodes and are found in peripheral tissues. They develop from T cells. Some T cells differentiate into effector cells while others differentiate into memory T cells that continue to offer protection against known and recognized pathogens. Unlike naïve T cells, memory T cells are not active fighters. They work by remembering foreign pathogens and quickly mounting a defense if that same pathogen returns at a later time. 

Main functions of memory T cells include: 

• Recognizing and responding to returning viruses, bacteria, and cancer cells

• Responding to antigens the immune system has previously encountered either through vaccination or infection