Week 1 Vocabulary Flashcards
What is innate immunity?
An arm of the immune system which protect against infection that relies on mechanisms that exist before infection, are capable of a rapid response to microbes, and react in essentially the same way to repeated infections.
What cell and/or cell types comprise the innate immune system?
The innate immune system includes epithelial barriers, phagocytic cells (neutrophils, macrophages), NK cells, the complement system, and cytokines, largely made by dendritic cells and mononuclear phagocytes, that regulate and coordinate many activities of the cells of innate immunity
What is adaptive immunity?
The form of immunity that is mediated by lymphocytes and stimulated by exposure to infectious agents. This arm of the immune system has the ability to display immune memory.
What is immune memory?
The process whereby cells of the adaptive immune system retain memory cells where it can then provide a more robust defense against priorly encountered pathogens.
What are the two subsets of the adaptive immune system?
1) Humoral immunity: mediated by B lymphocytes as well as their antibodies.
2) Cell mediated immunity: mediated by T lymphocytes which control immune response via T cells.
What are cytokines? What are the three main cytokines one should be aware of?
1) A large family of structurally homologous low molecular weight cytokines that stimulate leukocyte chemotaxis, regulate the migration of leukocytes from the blood to tissues by activating leukocytes integrins, and maintain the spatial organization of different subsets of lymphocytes and antigen-presenting cells within lymphoid organs.
2) IL-6, IL-1, and TNF-alpha are the three pro-inflammatory cytokines one should be aware of.
What is inflammation?
A complex reaction of vascularized tissue to infection or cell injurty that involves extravascular accumulation of plasma proteins an dleukocytes. Acute inflammation is a common result of innate immune responses, and local adaptive immune responses can also promote inflammation. Although inflammation serves a protective function in controlling infections and promoting tissue repair, it can also cause tissue damage and disease.
What is a pathogen?
Anything that can produce a disease.
What is phagocytosis?
The process by which certain cells of the innate immune system, including macrophages and neutrophils, engulf large particles such as intact microbes. The cell surrounds the particle with extensions of its plasma membrane by an energy—and cytoskeleton-dependent process; this process results in the formation of an intracellular vesicle called a phagosome, which contians the ingested particle.
What is opsinization?
A process by which proteins bind to a pathogen and facilitate it’s uptake and phagocytosis.
What is a Macrophage (MΦ)?
A tissue-based phagocytic cell derived from fetal hematopoietic organs or blood monocytes that plays important roles in innate and adaptive immune responses. Macrophages are activated by microbial products such as endotoxin and by T cell cytokines such as IFN-γ. Activated macrophages phagocytose and kill microorganisms, secrete proinflammatory cytokines, and present antigens to helper T cells. Macrophages may assume different morphological forms in different tissues, including the microglia of the central nervous system, Kupffer cells in the liver, alveolar macrophages in the lung, and osteoclasts in bone.
What is a Neutrophil?
aka polymorphonuclear leukocyte, PMN) a phagocytic cell characterized by a segmented lobular nucleus and cytoplasmic granules filled with degradative enzymes. PMNs are the most abundant type of circulating white blood cells and are the major cell type mediating acute inflammatory responses to bacterial infections.
What are NK cells?
A subset of innate lymphoid cells that function in innate immune responses to kill microbe infected cells by direct lytic mechanisms.
They are a lymphoid progenitor, too.
How are NK cells activated?
Their activation is regulated by a combination of cell surface stimulatory and inhibitory receptors, the latter recognizing self MHC molecules.
What are Granulocytes?
A category of white blood cells characterized by the presence of granules in their cytoplasm. They are also referred to as polymorphonuclear leukocytes (PMN, PML. Or PMNL) because of the varying shapes of the nucleus. They are produced in the bone marrow.
What are Dendritic Cells?
Bone-marrow derived cells found in epithelial and lymphoid tissues that are morphologically characterized by thin membranous projections. Many subsets of dendritic cells exist with diverse functions. Classical dendritic cells function as innate sentinel cells and become APCs for naïve T lymphocytes upon activation, and they are important for initiation of adaptive immune responses to protein antigen. Immature (resting) classical dendritic cells are important for induction of tolerance to self antigens. Plasmacytoid dendritic cells produce abundant type 1 interferons in response to exposure to viruses.
Which type of cell of the innate immune system links the adaptive and innate immune system?
Dendritic cells.
What is the general time line for the adaptive immune system? What about the innate immune system?
A few hours for the innate immune system, and five days to a week for the adaptive immune system.
Lymphocytes
Any of three subtypes of white blood cell in a vertebrate’s immune system. Including all B cells, T cells, and NK cells. They are derived form bone marrow.
B cell
The only cell type capable of producing antibody molecules and therefore the mediator of humoral immune responses. B lymphocytes, or B cells, develop in the bone marrow, and mature B cells are found mainly in lymphoid follicles in secondary lymphoid tissues, in bone marrow, and in low numbers in the circulation.
Describe passive immunity?
The process by which one receives antibodies in serum which provides protection against specific microbial pathogens but does not provide any sort of immune memory.
T cell
(aka T lymphocyte ) The key component of cell-mediated immune responses in the adaptive immune system. T lymphocytes mature in the thymus, circulate in the blood, populate secondary lymphoid tissues, and are recruited to peripheral sites of antigen exposure. They express antigen receptors (TCRs) that recognize peptide fragments of foreign proteins bound to self MHC molecules. Functional subsets of T lymphocytes include CD4+ helper T cells and CD8+ CTLs.
Hematopoiesis
The development of mature blood cells, including erythrocytes, leukocytes, and platelets, from pluripotent stem cells in the bone marrow and fetal liver. Hematopoiesis is regulated by several different cytokine growth factors produced by bone marrow stromal cells, T cellls, and other cell types.
Respiratory burst
The process by which reactive oxygen intermediates such as superoxide anion, hydroxyl radical, and hydrogen peroxide are produced in macrophages and polymorphonuclear leukocytes. The respiratory burst is mediated by the enzyme phagocyte oxidase and is usually triggered by inflammatory mediators such as LTB4, PAF, and TNF, or by bacterial products, such as N-formylmethionyl peptides.
What are the Primary Lymphoid Organs and how do they relate to lymphocytes?
Where lymphocytes are formed and mature. The two main lymphatic organs are the red bone marrow and the thymus gland.
What are the Secondary Lymphoid Organs and how do they relate to lymphocytes?
Lymphoid tissues are arranged in different ways. These tissues are also where lymphocytes are activated which includes the lymph nodes, tonsils, spleen, and mucosa associated lymphoid tissues (MALT).
What is NAPDH?
Cofactor used in anabolic reactions.
What is Humoral Immunity?
The type of adaptive immune response mediated by antibodies produced by B lymphocytes. Humoral immunity is the principal defense mechanism against extracellular microbes and their toxins.
What is Cell Mediated Immunity (CMI)?
The form of adaptive immunity that is mediated by T lymphocytes and serves as the defense mechanism against various types of microbes that are taken up by phagocytes or infect non-phagocytic cells. Cell-mediated immune responses are designated by the “cluster of differentiation” or CD number.
What is Bradykinin?
An inflammatory mediator, which causes blood vessels to dialate, which leads to a drop in blood pressure. This also makes capillaries leakier, allowing blood components to enter tissues. This also plays a part in inflammation, causing redness swelling, and warmth.
What are PAMPs?
Pathogen associated molecular patterns. Structures produced by microorganisms but not mamalian host cells, which are recognized by and stimulate the innate immune system. Examples include bacterial lipopolysaccharide and viral double-stranded RNA.
What is PGE2?
Prostaglandin E2 is the prostaglandin that ultimately induces fever, suppresses T cell receptor signaling, and may resolve inflammation.
What are PRRs?
Pattern Recognition Receptors are Signaling receptors of the innate immune system that recognize PAMPs and DAMPs, and thereby activate innate immune responses. Examples include Toll-like receptors (TLRs) and Nod-like receptors (NLRs).
