Antigen presenting cell

Antigen Presenting Cell

Antigen presenting cells (APCs) (pronounced: an-ti-jen pre-sen-ting cells) are a group of immune cells that mediate the cellular immune response by processing and presenting antigens for recognition by certain lymphocytes such as T cells. They are a vital component of the immune system and play a crucial role in initiating an immune response.

Etymology

The term "antigen presenting cell" is derived from the function of these cells. "Antigen" is a substance that can induce an immune response, "presenting" refers to the action of these cells in presenting the antigen to the immune system, and "cell" refers to the biological unit.

Function

Antigen presenting cells capture antigens, process them, and then present them on their surface to T cells. This process is crucial for the activation of T cells, which cannot recognize antigens on their own. The interaction between the T cell receptor and the antigen-MHC complex on the APC leads to T cell activation and the immune response.

Types of Antigen Presenting Cells

There are three main types of antigen presenting cells: Dendritic cells, Macrophages, and B cells. Each of these cells has a different role in the immune response, but all are capable of presenting antigens to T cells.

• Dendritic cells are the most potent APCs and are primarily responsible for initiating the immune response. They capture antigens in the tissues and then migrate to the lymph nodes to present the antigens to T cells.

• Macrophages are large white blood cells that are involved in the destruction of bacteria and other pathogens. They can also present antigens to T cells, but their main role is in phagocytosis and the innate immune response.

• B cells are a type of lymphocyte that can act as APCs. They are primarily involved in the humoral immune response and produce antibodies against antigens.

Related Terms

• Immune response is the reaction of the immune system to foreign substances or antigens.

• T cells are a type of white blood cell that play a central role in cell-mediated immunity.

• Antigen is a substance that can induce an immune response.

• MHC complex is a set of cell surface proteins essential for the acquired immune system to recognize foreign molecules in vertebrates.

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