Week 2 Vocabulary Flashcards
What is TLR-4?
A toll-like receptor (TLR) which detects lipopolysaccharides from Gram-Negative bacteria. It is located on the surface of the cell membrane.
What is unique about TLR-4?
TLR-4 is unique in the fact that it is able to signal through MyD88, and TRIF. This allows it to activate NFkB, and IRFs.
What is TLR3,TLR7?
TRL proteins which recognizes dsRNA associated with viral infection and activates NF-kB, leading to IRF3 to lead to production of type 1 interferons. Both are located in the endosome. TLR3 signals through TRIF transcription factor which leads to IRFS which leads to the expression of type 1 interferon. TLR7 signals through MyD88 which goes through NF-kB transcription factor which produces TNF, IL-1, IL-6, CCL2, CXCL8, E-selectin, CD80, and CD86.
What is TLR-9? Where is it located? How does it signal through the cell?
An endosomal TLR which detects ssRNA, and CpG DNA. It signals through MyD88, and activates the transcription factors NF-kB and IRFs.
What are the three types of PRRs? Provide an example of each.
1) Secreted: Mannose binding lectin.
2) Endocytic: macrophage mannose receptor.
3) Signaling: toll like receptors.
What is RIG-I?
A family of PRR (pattern recognition receptor) which are involved in the recognition of viruses by the innate immune system. They are located within the cytoplasm of human cells, and detect viral replication through direct interacts with dsRNA and some member of the family can induce a cellular response.
What is Mannose Binding Lectin? Does it offer any other functions besides being a PRR?
A plasma protein that binds to mannose residues on bacterial cell walls and acts as an opsonin by promoting phagocytosis of the bacterium by macrophages. Macrophages express a surface receptor for C1q that can also bind MBL and mediate uptake of the opsonized organsims.
What is IL-12?
Interleukin 12, IFN lambda synthesis, increased cytotoxic cell activity.
What is an Acute Phase Response?
The increase in plasma concentrations of several proteins, called acute-phase reactants, that occurs as part of the early innate immune response to infections.
What is a Toll Like Receptor?
A family of pattern recognition receptors of the innate immune system that are expressed on the surface and in endosomes of many cell types and that recognize microbial structures, such as endotoxin and viral RNA, and transduce signals that lead to the expression of inflammatory and anti-viral genes.
What is TNF-alpha? What happens when it occurs systemically?
A cell signaling protein involved in systemic inflammation and is one of the cytokines that make up the acute phase reaction. It is mainly produced by activated macrophages, but it can be produced by many other cells. It mainly regulates immune cells, being able to induce ferver, apoptotic cell death, cachexia, inflammation to inhibit tumorigenesis and viral replication.
What is Extravasation?
Leakage of a fluid out of its container, specifically the movement of white blood cells from the capillaries to the tissues which are surrounding them, also known as diapedesis.
What is Diapedesis?
The movement or passage of blood cells through the walls of vessels and capillaries as part of the inflammatory response.
What is CXCL-8?
A chemokine which is produced by macrophages and other cells which induces chemotaxis in target cells, and phagocytosis.
What is IL-6?
Cytokine produced by macrophages, endothelial cells, and T cells. This causes synthesis of acute phase proteins in liver and B cell proliferation of antibody-producing cells.
What is Type 1 Interferon?
A type of cytokines named for their ability to interfere with viral infections but have other important immunomodulatory functions. Type one interferons include INF-alpha and interferon-beta whose main function is to prevent viral replication in cells.
What’s important about Lipopolysaccharides?
Large molecules consisting of a lipid and a polysaccharide composed of O-antigen outer core and an inner core joined by a covalent bond. They are common on Gram-negative bacteria. It acts as a prototypical endotoxin because it reacts to various TLR expressing cell types.
What is an Autocrine Factor?
A molecule that acts on the same cell that produces the factor. For example, IL-2 is an autocrine T cell growth factor that stimulates mitotic activity of the T cell that produced it.
What is a Paracrine factor?
Occurs between local cells where the signal elicits a quick response and lasts only a short amount of time due to the degradation of the paracrine ligands.
What is an Endocrine factor?
Occurs between distant cells and is mediated by hormones released from specific endocrine cells that travel to target cells, producing a slower, long-lasting response.
What is LFA-1?
Lymphocyte function-associated antigen 1, found on all T cells, and on B cells, macrophages, and neutrophils and is involved in recruitment to the site of infection. It binds to ICAM-1 on APCs and functions as an adhesion molecule.
What is ICAM?
A gene which encodes a intercellular adhesion molecule continuously present in low concentrations in the membranes of leukocytes and endothelial cells. Upon cytokine stimulation, the concentration dramtically increases, and can be induced by IL-1, TNF, and when activated, leukocytes bind to endotheial cells via ICAM-1/LFA-1 and then transmigrate into tissues.
What is E-Selectin?
A cell adhesion molecule expressed only on endothelial cells activated by cytokines, and is encoded by the SELE gene.
What is Sialyl LewisX?
Places a role in cell to cell recognition process. One of the most important blood group antigens and is displayed on the terminus of glycolipids that are present on the cell surface. The determinant was E-selectin, and is important in leukocyte tethering and rolling. It binds to E-selectin.
What is an Endogenous Pyrogen?
It is a low-molecular-weight protein that is produced by phagocytic leukocytes in response to stimulation by exogenous pyrogens and released into circulation.
What is Interferon Response Factor (IRF)?
A family of proteins which regulate transcription of interferons, which can act as inhibitors or activators of various genes.
What is an Activating Receptors?
For NK cells, the constitutively expressed molecule(s) which lead to the activation of NK cells which then go out and destroy damaged or infected cells.
What is NFк-Β?
Nuclear factor кΒ a family of transcription factors composed of homodimers or heterodimers of proteins homologus to the c-Rel protein. NF-kB proteins are required for the inducible transcription of many genes important in both innate and adaptive immune responses.
What is the missing self hypothesis?
One function of NK cells is to recognize and eliminate cells that fail to express self major histocompatibility complex (MHC) class I molecules.
