hepatic immune response

Definition

Target type: biologicalprocess

An immune response taking place in the liver. [GO_REF:0000022, GOC:jal, ISBN:0781735149]

The liver, a vital organ in metabolism and detoxification, also plays a crucial role in immune responses. Its unique anatomical structure and cellular composition create a complex and dynamic immune landscape. The hepatic immune response is initiated when the liver encounters pathogens, foreign antigens, or damaged cells. This intricate process involves a series of coordinated events, including the activation of various immune cells, the production of cytokines and chemokines, and the generation of adaptive immune responses.

**1. Innate Immune Response:** The liver's first line of defense is its innate immune system. Kupffer cells, resident macrophages in the liver sinusoids, are highly phagocytic and actively engulf pathogens and cellular debris. They also secrete pro-inflammatory cytokines like TNF-alpha, IL-6, and IL-1, which trigger the recruitment of other immune cells to the site of infection. Natural killer (NK) cells, another component of the innate immune system, are responsible for eliminating virus-infected cells and tumor cells. Their activation is stimulated by various factors, including interferon-gamma and IL-12.

**2. Adaptive Immune Response:** The liver harbors lymphocytes, both T cells and B cells, which contribute to the adaptive immune response. When antigens are presented by antigen-presenting cells (APCs) such as Kupffer cells or dendritic cells, T cells become activated and differentiate into effector cells. These effector T cells can eliminate infected or cancerous cells through direct cytotoxicity or by secreting cytokines like IFN-gamma and TNF-alpha. B cells, upon receiving signals from T cells and cytokines, differentiate into plasma cells, which produce antibodies that specifically target the invading pathogens.

**3. Liver-Specific Features:** The liver's immune response is further characterized by unique features:
* **Hepatic Sinusoids:** The liver sinusoids are lined by specialized endothelial cells that allow for the passage of immune cells and molecules, facilitating immune surveillance.
* **Hepatic Lymphatics:** The liver lymphatic system plays a role in draining antigens and immune cells from the liver.
* **Liver Tolerance:** The liver maintains a balance between immune activation and tolerance, preventing excessive inflammation and tissue damage. Mechanisms like the expression of tolerogenic molecules and the presence of regulatory T cells contribute to this tolerance.

**4. Hepatic Immune Dysregulation:** Dysregulation of the hepatic immune response can lead to various liver diseases, including autoimmune hepatitis, viral hepatitis, and liver fibrosis. In these conditions, the immune system mistakenly targets liver cells, causing inflammation and damage.

The hepatic immune response is a complex and tightly regulated process that involves various cell types, signaling pathways, and immune mediators. Its dysregulation can lead to serious liver diseases, while its proper function is essential for maintaining liver health and protecting the body from infection.'
"

Proteins (1)

Compounds (2)