What are antigen presenting cells of the liver?

Clearly, the liver is a tissue in which immune responses are often suboptimal. One key issue is that of antigen presentation; the liver contains dendritic cells (DC) and resident mononuclear phagocytes, but there is evidence that other hepatic cell types act as APC.

What is a presenting antigen?

Definition. Antigen-presenting cells (APCs) are a heterogeneous group of immune cells that mediate the cellular immune response by processing and presenting antigens for recognition by certain lymphocytes such as T cells. Classical APCs include dendritic cells, macrophages, Langerhans cells and B cells.

What are professional antigen presenting cells?

Professional antigen presenting cells (APC), i.e., dendritic cells (DC), monocytes/macrophages, and B lymphocytes, are critically important in the recognition of an invading pathogen and presentation of antigens to the T cell-mediated arm of immunity.

Why is the liver tolerogenic?

The liver is a tolerogenic organ with exquisite mechanisms of immune regulation that ensure upkeep of local and systemic immune tolerance to self and foreign antigens, but that is also able to mount effective immune responses against pathogens.

Are there antigen presenting cells in the liver?

Experiments support the role not only of liver dendritic cell subsets but also of diverse subsets of unconventional antigen-presenting cells in inducing immune suppression. The literature on this topic is controversial and sometimes contradictory, making it difficult to formulate a unified model of antigen handling and T cell priming in the liver.

How are liver sinusoidal endothelial cells respond to antigen?

Both Kupffer cells and liver sinusoidal endothelial cells (LSEC) take up antigen from the blood and present it to CD4+ T cells together with co-stimulatory molecules. However, both cell types also respond to lipopolysaccharide endotoxin (LPS) via their TLR4 receptors; in both cases this leads to secretion of IL-10.

How are antigen presenting cells used to induce immune suppression?

In this review, the induction of local, intrahepatic tolerance is explored from the perspective of antigen presentation. Experiments support the role not only of liver dendritic cell subsets but also of diverse subsets of unconventional antigen-presenting cells in inducing immune suppression.

Where are CD8 + T cells located in the liver?

The liver sinusoidal endothelial cells are penetrated by holes (fenestrations), through which a CD8+ T cell can make direct contact with an underlying hepatocyte. Between the endothelial cells and the hepatocytes is the Space of Disse, in which reside hepatic stellate cells (Ito cells), a specialized pericyte with immunological properties.