Innate Immunity and Antigen Recognition

A multi-protein complex that assembles in the cytoplasm of cells in response to microbes or cell injury. Its main function is to activate caspase-1 and produce inflammatory cytokines.

A type of white blood cell produced in the bone marrow and circulating in the blood. They are rapidly recruited to sites of inflammation, where they engulf pathogens and kill them.

A type of white blood cell that is larger than a neutrophil and has a distinctive horseshoe-shaped nucleus. They can ingest microbes in both blood and tissue.

A type of white blood cell that develops from monocytes and is found in both blood and tissues. They are named differently depending on their location in the body, such as Kupffer cells in the liver, microglial cells in the brain, and alveolar macrophages in the lungs.

A process by which phagocytes engulf and destroy pathogens. It involves several steps, including binding of the microbe to the phagocyte receptor, engulfment, formation of a phagosome, fusion with a lysosome, and killing of the microbe by reactive oxygen species, nitric oxide, and lysosomal enzymes.

A system of proteins in the blood that helps to protect the body from infection. It can be activated by three pathways: the classical pathway, the alternative pathway, and the lectin pathway.

A type of epithelial cell that forms a physical barrier to infection. It can also kill microbes by producing antibiotics and by recruiting other immune cells.

A type of immune response that is present from birth and does not require prior exposure to the pathogen. It is a rapid and non-specific response that acts as the first line of defense against infection.

The accumulation and activation of leukocytes, plasma proteins, and other immune cells at the site of infection or injury. This is the hallmark of inflammation, aiming to clear the infection and initiate repair.

A type of immune response that is acquired through exposure to specific pathogens. It involves the development of memory cells and antibodies, making it more efficient in responding to subsequent infections.

A complex process involving cell communication and signaling pathways, triggered by the recognition of PAMPs or DAMPS by immune cells, ultimately resulting in the activation of an immune response.

Microbial molecules like lipopolysaccharides and viral RNA that are recognized by pattern recognition receptors (PRRs) to initiate an immune response. These molecules are unique to microbes and are not found in human cells.

Self-derived molecules released during cellular stress or tissue damage that are recognized by pattern recognition receptors (PRRs) to initiate an immune response. These molecules are normally not found in the extracellular space, but are released during cell injury.

A type of pattern recognition receptor (PRR) that plays a crucial role in innate immunity by recognizing specific microbial molecules, triggering signaling pathways and leading to the activation of immune responses. They are found on the surface of immune cells.

A transcription factor that is activated by TLR signaling and plays a critical role in initiating inflammatory responses and promoting adaptive immunity. It is a powerful regulator of gene expression within the immune system.

A protein that binds to sugars on the surface of pathogens, marking them for destruction by the immune system.

The point where all three complement pathways converge, leading to a robust immune response.

The process by which C3b coats pathogens, making them more easily recognized and engulfed by phagocytes.

A type of white blood cell that plays a key role in innate immunity, particularly against viral infections. They can directly kill infected cells.

A protein expressed on the surface of healthy cells that inhibits NK cell activation, preventing them from killing healthy cells.

A type of signaling molecule that helps initiate and regulate inflammation, primarily produced by immune cells.

A cytokine that promotes the production of antibodies by B cells, important for adaptive immune responses

A cytokine that promotes the proliferation of both T cells and NK cells, important for both adaptive and innate immunity.

Leukocytes squeeze through the endothelial layer of blood vessels, allowing them to enter the surrounding tissues and reach the site of inflammation or infection.

Leukocytes follow a chemical trail created by chemokines to directly locate the source of an infection or injury.

Type I interferons are antiviral proteins that bind to receptors on infected cells, triggering an antiviral cascade.

Anti-inflammatory cytokines, suppressor proteins, and receptor agonists help to control inflammation, preventing excessive tissue damage.

Some bacteria have evolved ways to evade the innate immune system, like hiding from phagocytes or resisting the effects of reactive oxygen species.

Lymphocytes, part of the adaptive immune system, require two signals to activate: a specific antigen and a signal from the innate immune system.

Cytokines are small proteins that act as messengers in the immune system, and they are classified based on their effects, such as pro-inflammatory or anti-viral.

IL-10 and TGF-beta are anti-inflammatory cytokines that regulate inflammatory responses and suppress immune activation.