Memory t cell

Memory T cells are a subset of T cells that are part of the immune system. They are long-lived and can quickly expand to large numbers of effector T cells upon re-exposure to their cognate antigen, thus providing the immune system with "memory" against past infections.

Overview

Memory T cells were originally thought to belong to either the effector T cell or the naive T cell subset, but it is now known that they make up a distinct group of cells. These cells can be identified by their expression of specific cell surface proteins including CD45RO, CCR7, CD28, and CD95.

Types of Memory T cells

There are several types of memory T cells in the body. These include:

• Central memory T cells (T_CM): These cells express CD45RO, CCR7 and L-selectin, which enable them to migrate to and reside in lymph nodes and Peyer's patches. They have high proliferative potential and can differentiate into effector T cells.

• Effector memory T cells (T_EM): These cells express CD45RO but lack expression of CCR7 and L-selectin. They have immediate effector function and reside in peripheral tissues.

• Resident memory T cells (T_RM): These cells reside in peripheral tissues and do not recirculate. They are important for providing immediate protection against reinfection in non-lymphoid tissues.

• Virtual memory T cells: These cells are a population of memory phenotype CD8+ T cells that have arisen in response to homeostatic proliferation rather than antigen exposure.

Function

Memory T cells play a crucial role in the immune response. Upon re-exposure to their cognate antigen, they are able to rapidly proliferate and differentiate into effector T cells. This results in a quicker and more robust immune response compared to the primary response.

Clinical significance

Memory T cells are of particular interest in the field of vaccine development. The goal of vaccination is to induce a strong memory T cell response that can protect against future infection. In addition, memory T cells are also of interest in the field of cancer immunotherapy, where the aim is to harness the power of the immune system to fight cancer.

See also

• T cell
• Immune system
• Antigen
• Vaccine
• Cancer immunotherapy