VCE Biology unit 3/4 - Immune system

Flash cards for immune system unit 3/4 vce biology

adaptive immune response

immune response directed against a specific antigen that also retains memory of that antigen, responding with a secondary response on subsequent exposure to the same antigen

antibiotic

naturally produced or synthetic compound that is toxic to bacteria

antigen

large molecule, usually a protein/polysaccharide, that generates an immune response

antiseptic

substance that kills or inhibits the growth of micro-organisms on external surfaces of living things

apoptosis

programmed series of events that lead to cell death as a result of dismantling of the internal contents of the cell by various enzymes, including caspases

bacterial capsule

polysaccharide layer surrounding some bacteria that makes them resistant to phagocytosis and thus more virulent

bacteriophage

virus that infects bacteria

basophil

circulating leukocyte that secretes histamines

binary fission

asexual mode of reproduction in which a unicellular organism grows and then divides into two cells, forming two separate organisms

chemokine

type of cytokine that induces chemotaxis

chemotaxis

movement of an organism or cell along a chemical concentration gradient towards a chemokine (positive) or away from a chemokine (negative)

chitin

fibrous substance containing polysaccharides that forms the tough outer shell of insects and fungi

cilia

slender hair-like structures projecting from the cell surface that beat against fluid outside the cell

companion plant

plant that is grown together with another plant because one species involves the growth of the other

complement

number of small proteins found in the blood that, when activated, promote chemotaxis, cell lysis, and phagocytosis

cytokines

signalling molecules that coordinate inflammation and immune responses, and that leukocytes use to communicate with one another, includes interleukins and interferons

DAMP (damager- or danger-associated molecular pattern)

a body (or plant) component that is released during tissue damage, such as internet cellular components that stimulate innate immune responses

defensin

small antimicrobial peptide secreted by virtually all plants and animals

dendritic cells

antigen-presenting cells that phagocytose and present antigens to cells of the adaptive immune system

endospore

tough, dormant structure for asexual reproduction formed inside some bacterial cells; resistant to extreme temperatures, chemicals, and drying out

eosinophil

leukocyte that secretes powerful enzymes capable of rupturing multicellular pathogens

epitope

small part of an antigen that is specifically bound by antigen receptors such as BCRs and TCRs

fever

increased body temperature

flagellum

helical filament that rotates to give bacteria locomotion

granulocyte

leukocyte containing intracellular granules

histamine

chemical released by mast cells and basophils that increases blood flow and the permeability of capillaries

host

organism in which a parasite lives

immune

having resistance to infection by a specific pathogen

immune system

complex network of cells, tissues, and organs in the body that detects differences between self molecules and foreign organisms, and mounts an immune response that results in formation of memory lymphocytes

inflammation

innate response to infection or damage that causes swelling, pain, heat, and redness

innate immune response

response to a pathogen that is not specific and does not generate antibodies or memory lymphocytes

interferon

type of cytokine produced by the cells of the immune system in response to challenges by foreign agents such as viruses, bacteria, parasites, and tumour cells

interleukin

subset of cytokines that assist with coordination of cells involved in immune responses

leukocyte

white blood cells

lymphatic system

system of organs (thymus, bone marrow, spleen, lymph nodes, network of vessels) and lymph fluid that are involved in transporting lymphocytes and in removing foreign matter

lymphocyte

type of leukocyte involved in adaptive immune responses

lysis

process of a cell bursting

lysozyme

antibacterial enzyme found in tears, saliva, and other body fluids

macrophage

large white blood cell in tissues that phagocytoses pathogens; originate as monocytes in circulation

mast cell

located in the tissues; when activated, releases granules containing histamine

microflora

community of micro-organisms, including fungi and bacteria, that live in or on another living organism

monocyte

white blood cell that circulates in the blood and matures into a macrophage when it moves from the blood into the tissues

mucous membrane

mucus-secreting membrane that lines the respiratory, excretory, and reproductive tracts

natural killer cell

circulating leukocyte that kills body cells infected with a virus or transformed by cancer

necrosis

cell deaths that results from tissue damage or infection; results in inflammation

neutrophil

phagocytic leukocyte found in the blood and tissues

NLR (NOD-like receptor)

type of PRR; intracellular sensors of PAMPs and DAMPs

non-self

molecules not recognised by the immune system as being part of the organism

non-specific

describes a response that is the same regardless of the type of pathogen

obligate

restricted to a particular way of life

opsonisation

process in which a pathogen is coated with antibodies and/or complement and marked for phagocytosis

parasite

organism that lives in or on a host organism and derives nutrients from the host, at the host's expense

pathogen

organism foreign to the body that can cause disease

PAMP (pathogen-associated molecular pattern)

broad molecular pattern commonly shared by a number of pathogens and not normally present in the host

PRR (pattern recognition receptor)

receptor that recognises molecular patterns commonly shared by a number of pathogens; includes NLRs and TLRs

phagocyte

cell capable of phagocytosis; includes macrophages, dendritic cells, and neutrophils

phagocytosis

bulk transport of solids into a cell inside a vesicle

phagolysosome

membrane-vesicle formed from the fusion of a phagosome and lysosome

phagosome

membrane-bound vesicle formed around a particle during phagocytosis

phytoalexin

chemical produced by plants under attack

platelet

cell fragment found in the blood involved in blood clotting

prion

infectious protein that can cause other unaffected prion proteins in the brain to take the affected form, causing TSE

self

describes agents (eg. cells, organisms, and substances) that are recognised by the immune system of an organism as being part of that organism; the immune system tolerates all cells int he body without attacking them because cells carry marker molecules that identify them as self

self-antigen

antigen or molecule that is a normal body component

specific response

adaptive immune response directed against a particular antigen that retains immunological memory of that antigen

sterile inflammation

inflammation resulting from detection of DAMPs released during tissue injury in the absence of infection

systemic acquired resistance

a plant's reaction to invasion by a pathogen that leads to long-term resistance to a broad range of pathogens; 'systemic' refers to the whole body

TLR (toll-like receptor)

PRR in membranes that responds to PAMPs and DAMPs

vasodilation

dilation (widening) of blood vessels

virus

obligate intracellular pathogen able to use the host cell's machinery to replicate itself; usually consists of a nucleic acid surrounded by a protein coat

agglutination

when antigens or pathogens become stuck together because of antibody binding

antibody

a Y-shaped protein produced by plasma cells that binds to a specific antigen; also called immunoglobulin

APC (antigen presenting cell)

a cell that displays peptides derived from processed antigens on MHC class 2 molecules for presentation to helper T cells; includes B cells, macrophages, and dendritic cells

BCR (B cell receptor)

surface-bound antibody that serves as a receptor so that B cells are able to detect antigens

B cell (B lymphocyte)

class of lymphocytes; once activated, they are characterised by the production of antibodies

clonal selection

process in which lymphocytes bind to antigen they recognise as complementary

clonal expansion

process in which lymphocytes that have bound to an antigen divide rapidly and become more numerous than other clones

cytotoxic T cells (killer T cells/lymphocytes)

class of lymphocytes that destroy virally infected or cancerous cells by secreting proteins that cause apoptosis

helper T cells (helper T lymphocytes)

class of lymphocytes that aid cytotoxic T cells, B cells, and macrophages by secreting cytokines and providing contact-dependent signalling

humoral immune response

immune response mediated by antibodies

interstitial fluid

fluid that lies in the spaces between cells and drains into the lymphatic system; also known as tissue/extracellular fluid

isotype

substance of immunoglobulin; each isotype (IgG, IgM, IgA, IgE, and IgD( performs a different function

lymph

colourless fluid that originates from the extracellular (tissue) fluid

lymph node

immunological organ in which antigens are trapped or delivered by phagocytes for presentation to lymphocytes and initiation of an adaptive response

MALT

mucosal-associated lymphoid tissue; secondary lymphoid tissue in which adaptive immune responses occur

memory cell

cells that remain in the body for months/years but don't secrete antibodies; only carry them around, allowing them to recognise the same pathogen if it revisits, causing the cell to be activated and then rapidly divide to form plasma cells that produce antibodies

MHC (major histocompatibility complex)

protein markers found on the cell surface that are important in distinguishing self from non-self; two classes

MHC class 1

found on all cells

MHC class 2

found only on APCs

MHC restriction

refers to the fact that T cells can only recognise antigens that are presented on MHC proteins

neutralisation

process by which antibodies prevent toxins from acting; that is, by binding to them and blocking them from binding to their targets

plasma cell

effector B cell that has differentiated to become highly specialised for producing antibodies

primary lymphoid organs

bone marrow and thymus; responsible for the production and maturation of immune cells

primary response

response generated when an antigen is encountered for the first time; contrasted with the secondary response

regulatory T cells (lymphocytes)

class of lymphocytes that help to negatively regulate the immune response

secondary lymphoid organ

organ that provides an environment for the initiation of the immune response; includes lymph nodes, spleen, and MALT

secondary response

response generated when the body encounters a pathogen to which it has previously generated an immune response; involves reactivation of memory lymphocytes and occurs more rapidly and with greater magnitude than the primary response

self-tolerance

deletion or inactivation of lymphocyte clones that can bind to self-antigens to prevent an immune response to these antigens

TCR (T cell receptor)

protein receptor found on the surface of T cells; binds to antigens presented on MHC proteins

active immunity

Immunity formed by stimulation of the immune system with an antigen and the generation of plasma and memory cells - body produces it's own antibodies