What is meant by macrophage polarization?

Macrophage polarization refers to the process by which macrophages produce distinct functional phenotypes as a reaction to specific microenvironmental stimuli and signals (3, 10–12). Macrophages can be polarized into classically activated (M1) and alternatively activated (M2) macrophages.

Why is M1 macrophage polarized?

In infected tissues, macrophages are first polarized to pro-inflammatory M1 phenotype to assist the host against pathogens. Subsequently, macrophages are polarized to form an anti-inflammatory response to the M2 phenotype and repair damaged tissue.

What is monocyte Polarisation?

Monocytes and macrophages, which are important players in the innate immune system, are highly plastic and are heterogeneous in their phenotype and function. Depending on the environmental cues, monocytes migrate to the tissues and differentiate into macrophages and become polarized.

How do you induce macrophages?

M1 macrophages can be induced by the Th1 cytokines tumor necrosis factor (TNF)-α, interferon (IFN)-γ and bacterial components such as lipopolysaccharide (LPS). Activated M1 macrophages phagocytose and destroy microbes, eliminate tumor cells and present antigens to T cells to evoke an adaptive immune response.

What are the different types of macrophages?


Type of macrophage Location
Alveolar macrophage Lung alveoli
Kupffer cells Liver
Microglia Central nervous system
Splenic macrophages (marginal zone, metallophilic and red pulp macrophages) Spleen marginal zone, red and white pulp

How many macrophages are there?

Human macrophages are about 21 micrometres (0.00083 in) in diameter and are produced by the differentiation of monocytes in tissues….Types.

Cell Name Anatomical Location
Adipose tissue macrophages Adipose tissue (fat)
Monocytes Bone marrow / blood
Kupffer cells Liver
Sinus histiocytes Lymph nodes

What do macrophages do?

Macrophages are specialised cells involved in the detection, phagocytosis and destruction of bacteria and other harmful organisms. In addition, they can also present antigens to T cells and initiate inflammation by releasing molecules (known as cytokines) that activate other cells.

What is the difference between M1 and M2 macrophages?

M1 macrophages produce nitric oxide (NO) or reactive oxygen intermediates (ROI) to protect against bacteria and viruses. M2 macrophages are alternatively activated by exposure to certain cytokines such as IL-4, IL-10, or IL-13. These macrophages are associated with wound healing and tissue repair.

What are macrophages function?

Macrophages are key components of the innate immune system that reside in tissues, where they function as immune sentinels. They are uniquely equipped to sense and respond to tissue invasion by infectious microorganisms and tissue injury through various scavenger, pattern recognition and phagocytic receptors1,2,3,4.

How macrophages are formed from monocytes?

Macrophages are formed through the differentiation of monocytes, one of the major groups of white blood cells of the immune system. When there is tissue damage or infection, the monocytes leave the bloodstream and enter the affected tissue or organ and undergo a series of changes to become macrophages.

What is macrophage chemotaxis?

One mechanism that could account for the local accumulation of wandering cells such as macrophages is chemotaxis, the unidirectional migration of cells along a concentration gradient of a chemoattractant.

What are the 2 types of macrophages?

Two Types of Macrophages: M1 and M2 Macrophages.