Immunology Terms

Question 1

any molecule that can bind specifically to an Ab. Their name arises from their
ability to generate antibodies.

Answer 1

antigen (Ag)

Question 2

these molecules have a unique Ag binding pocket that enables it to bind specifically to its corresponding antigen. They are produced by B cells and plasma cells in response to infection or immunization, bind to and neutralize pathogens or prepare them for uptake and destruction by phagocytes.

Answer 2

Antibody (Ab)

Question 3

this type of immunization is involved with Ag

Answer 3

active immunization

Question 4

this type of immunization involves the transfer of pre-existing Ab to a non-immunized individual

Answer 4

passive immunization

Question 5

the response of Ag-specific lymphocytes, including development of immunological memory. They are generated by clonal selection of lymphocytes and as such are distinct from innate (non-adaptive) phases of immunity.

Answer 5

adaptive immune response or acquired immunity

Question 6

any substance that enhanced the immune response to an Ag with which it is mixed.

Answer 6

adjuvant

Question 7

the strength of binding of one molecule to another. High affinity Ab responses are an
objective of immunization

Answer 7

Affinity

Question 8

Ags that elicit hypersensitivity or allergic reactions

Answer 8

Allergens

Question 9

a response to innocuous environmental Ags or allergens due to pre-existing Ab or T cells. There are various immune mechanism or allergic reactions, but the most common is the binding of allergen to IgE Ab on mast cells that causes asthma, hay fever, and other common allergic reactions.

Answer 9

allergic reaction

Question 10

constriction of the bronchial tree due to an allergic reaction to inhaled Ag.

Answer 10

Allergic asthma

Question 11

an allergic reaction in the nasal mucosa, also known as hay fever, that causes runny nose, sneezing and tears.

Answer 11

Allergic rhinitis

Question 12

a graft of tissue from an allogeneic or non-self donor of the same species; such grafts are always rejected unless the recipient is immunosuppressed.

Answer 12

allograft

Question 13

systemic anaphylaxis is an allergic reaction to systemically administered Ag that causes circulatory collapse and suffocation due to tracheal swelling. It results from binding of Ag to IgE on connective tissue mast cells throughout the body, leading to the release of inflammatory mediators (i.e. histamine).

Answer 13

Anaphylactic shock

Question 14

the killing of Ab-coated target cells by cells with Fc receptors that recognize the Fc region of the bound Ab. Most ADCC is mediated by NK cells.

Answer 14

Ab-dependent cell-mediated cytotoxity (ADCC)

Question 15

describes the total variety of antibodies that an individual can make.

Answer 15

Ab repertoire

Question 16

non-covalently bound groups of Ag and Ab molecules which can vary in size from small, soluble complexes to large, insoluble complexes that precipitate out of solution

Answer 16

Ag:Ab complexes or immune complexes

Question 17

cells that normally initiate the responses of naive T cells to Ag by carrying out Ag processing then Ag presentation. To date, only dendritic cells, macrophages, and B cells have been shown to have this capacity. These cells must be able to display peptide fragments of Ag on appropriate MHC molecules and also carry co-stimulatory molecules on its surface.

Answer 17

Ag-presenting cells (APC)

Question 18

the enzymatic digestion of protein into peptides that bind within pockets of MHC molecules for presentation to T cells.

Answer 18

Ag processing

Question 19

involves the display of Ag as peptide fragments bound to MHC molecules on the surface of an Ag-presenting cell; all T cells recognize Ag only when it is presented in this way. All Ags must be processed into small peptides before they can be presented by MHC molecules.

Answer 19

Ag presentation

Question 20

programmed cell death

Answer 20

Apoptosis

Question 21

diseases in which the pathology is caused by immune responses to self Ags.

Answer 21

Autoimmune diseases

Question 22

describes immune responses directed at self Ags.

Answer 22

Autoreactivity

Question 23

white blood cells containing granules that stain with basic dyes, and which are thought
to have a function similar to mast cells (i.e.. in allergy).

Answer 23

Basophils

Question 24

one of the two major types of lymphocyte (T cells being the other). The Ag receptor on these cells is a cell-surface immunoglobulin. On activation by Ag, these cells differentiate into plasma cells producing high levels of Ab molecules of the same Ag-specificity as this receptor or into memory B cells.

Answer 24

B cell, or B lymphocyte

Question 25

surface molecules on red blood cells that are detectable with Ab from other individuals.

Answer 25

Blood group Ags

Question 26

the main site of hematopoiesis

Answer 26

bone marrow

Question 27

given after a primary immunization, to increase the state of immunity.

Answer 27

booster immunization

Question 28

describes any adaptive immune response in which Ag-specific T cells have the main role. In practice it is defined as all adaptive immunity that cannot be transferred with serum Ab.

Answer 28

Cell-mediated immunity

Question 29

sites of lymphocyte development

Answer 29

Central lymphoid organs

Question 30

proteins made by cells that affect the behaviour of other cells

Answer 30

Cytokines

Question 31

a family of small cytokines involved in migration and activation of cells. They have a central role in inflammatory responses and, increasingly, in normal immune regulation.

Answer 31

chemokines

Question 32

the selection and proliferation of Ag-specific lymphocytes in response to antigenic stimulation. It precedes their differentiation into effector cells. It is an essential step in adaptive immunity, allowing rare Ag-specific cells to increase in number so that they can effectively combat the pathogen that elicited the response

Answer 32

clonal expansion

Question 33

a population of cells all derived from a single starting cell.

Answer 33

clone

Question 34

the name for commonly used cell surface Ags that are useful in discriminating between different cell types

Answer 34

CD

Question 35

contains the Ag specific T cell receptor (highly variable between different T cell populations).

Answer 35

CD3 complex

Question 36

responsible for Ag recognition by forming Ag binding pockets analogous to those of Ab molecules.

Answer 36

Ag specific T cell receptor (highly variable between different T cell populations).

Question 37

a marker expressed on helper T cells

Answer 37

CD4

Question 38

associated with cytotoxic T cells

Answer 38

CD8

Question 39

molecules identical on different T cells.

Answer 39

CD4 and CD8

Question 40

a set of constitutively present plasma proteins that act together to attack extracellular pathogens.

Answer 40

complement system

Question 41

Complement can be activated spontaneously on certain pathogens

Answer 41

alternative pathway

Question 42

by Ab attached to the pathogen

Answer 42

classical pathway once a pathway is chosen then: The pathogen then becomes coated with complement proteins that aid pathogen removal by phagocytes or can kill the pathogen directory.

Question 43

cell-surface proteins on various cells that recognize and bind complement proteins that have bound an Ag. These receptors on phagocytes allow them to identify pathogens coated with complement proteins for uptake and destruction.

Answer 43

Complement receptors (CR)

Question 44

essentially the same as delayed-type hypersensitivity (DTH) in which T cells respond to Ags introduced by contact with skin.

Answer 44

contact hypersensitivity reaction

Question 45

the binding of Ab to an Ag that was not used to elicit that Ab. Thus, if Ab raised against X also binds Ag Y, it is said to cross-react with Ag Y.

Answer 45

cross-reaction

Question 46

lymphocytes that mediate pathogen removal without a need for further differentiation. They are distinct from naive lymphocytes, which must proliferate and differentiate before they can mediate effector functions, and memory cells, which must differentiate and often proliferate before they become these cells

Answer 46

Effector cells

Question 47

those by which pathogens are destroyed and cleared from the body. Innate and adaptive immune responses use most of the same effector mechanisms to eliminate pathogens.

Answer 47

Effector mechanisms

Question 48

white blood cells important in defense against parasitic infections; they are activated by the lymphocytes of the adaptive immune responses (also in asthma, allergy).

Answer 48

Eosinophils

Question 49

The movement of cells or fluid from within blood vessels to the surrounding tissues

Answer 49

extravasation

Question 50

these receptors bind the Fc (or constant) portion of antibody:the part that makes IgG distinct from IgA or IgE.

Answer 50

Fc receptors

Question 51

this type of therapy is the correction of a genetic defect via introduction of a heritable normal gene in vivo.

Answer 51

gene therapy

Question 52

a novel technique for inducing adaptive immunity. Plasmid DNA encoding a protein of interest is injected into muscle, transiently expressed, and elicits Ab and T-cell responses to the protein encoded by that DNA.

Answer 52

genetic immunization

Question 53

these centers are located in secondary lymphoid tissues (i.e.. spleen, lymph nodes) and are sites of intense B-cell proliferation, selection, maturation, and death (apoptosis) during Ab responses. These centers form around follicular dendritic cell networks when activated B cells migrate into lymphoid follicles.

Answer 53

germinal centers

Question 54

cells that can help B cells make Ab in response to antigenic challenge.

Answer 54

Helper CD4 T cells

Question 55

most efficient helper T cells that make the cytokines IL-4 , IL-5 and IL-13.

Answer 55

Th2

Question 56

cells are largely associated with cell mediated immunity and make IFNγ.

Answer 56

Th1

Question 57

HLA acronym

Answer 57

Human Leukocyte Ags

Question 58

what does MHC stand for

Answer 58

major histocompatibility complex

Question 59

Ab-mediated specific immunity. It can be transferred to unimmunized recipients by using immune serum containing specific Ab (i.e.. IV Ig for short lived passive immunity).

Answer 59

Humoral immunity

Question 60

Binding of Ab to a soluble Ag forms an _____?

Answer 60

immune complex

Question 61

the ability to resist infection

Answer 61

Immunity

Question 62

the system of lymphoid channels that drains extracellular fluid from the periphery via the thoracic duct to the blood. It includes the lymph nodes, Peyer's patches, and other organized lymphoid elements apart from the spleen, which communicates directly with the blood.

Answer 62

lymphatic system

Question 63

thin-walled vessels that carry lymph - the extracellular fluid that accumulates in tissues - back through the lymph nodes to the thoracic duct

Answer 63

Lymphatics

Question 64

one type of secondary lymphoid organ in which adaptive immune responses are initiated. They are found in many locations where lymphatic vessels converge, delivering Ag to Ag presenting cells, which display it to the many recirculating lymphocytes that migrate through the lymph node. Some of these cells will recognize the Ag and respond to it, triggering an adaptive immune response.

Answer 64

Lymph nodes

Question 65

organized tissues characterized by very large numbers of lymphocytes interacting with a non lymphoid matrix. Primary (or central) lymphoid organs, where lymphocytes develop are the thymus and bone marrow. Secondary (or peripheral ) lymphoid organs, in which adaptive immune responses are turned on include lymph nodes, spleen, and mucosal-associated lymphoid tissues, such as tonsils and Peyers patches.

Answer 65

Lymphoid organs

Question 66

large mononuclear phagocytic cells important in innate immunity

Answer 66

Macrophages

Question 67

important in controlling infection but can also cause damage to neighboring tissues.

Answer 67

Macrophage | activation

Question 68

a cluster of genes on human chromosome encoding a set of membrane glycoproteins called MHC molecules.

Answer 68

major histocompatibility complex (MHC)

Question 69

a process of selection that happens during intrathymic development in which thymocytes (T lymphocyte progenitors) recognize self and are deleted from the repertoire

Answer 69

negative selection

Question 70

the fluid component of blood containing water, electrolytes, and the plasma proteins but no cells.

Answer 70

Plasma

Question 71

terminally differentiated B lymphocytes. They are the main Ab-secreting cells of the body. They are found in the medulla (centre) of lymph nodes, in splenic red pulp, and in bone marrow.

Answer 71

Plasma cells

Question 72

white blood cells with multi-lobed nuclei and cytoplasmic granules. there are three main types, what are they?

Answer 72

Polymorphonuclear leukocytes (PMN) neutrophils with granules that stain with neutral dyes, eosinophils with granules that stain with eosin, and the basophils with granules that stain with basic dyes.

Question 73

the adaptive immune response at first exposure to Ag

Answer 73

primary immune response

Question 74

``` generates both (i) a primary immune response (initially IgM predominating, later IgG in serum or IgA in secretions) and (ii) immunological memory (hence the ability to mount secondary responses). ```

Answer 74

Primary | immunization (or priming)

Question 75

this is a common inflammatory joint disease probably due to an autoimmune response. The disease is accompanied by the production of _____ factor

Answer 75

Rheumatoid arthritis rheumatoid factor

Question 76

an IgM anti- (self) IgG that is sometimes also produced in normal immune responses at low concentrations without clinical effect.

Answer 76

rheumatoid factor

Question 77

the Ab response induced by a second or subsequent exposure to Ag

Answer 77

secondary Ab response

Question 78

A cell is said to be selected by Ag when its receptors encounter and bind that particular Ag. If the cell proliferates as a result, this is called _____?

Answer 78

positive selection

Question 79

this term is used to describe the failure to respond to the Ag

Answer 79

tolerance, when the Ag is borne of self tissues, tolerance is then called self tolerance

Question 80

when Ab against the infecting agent are first detectable in blood/serum.

Answer 80

seroconversion

Question 81

an organ containing a red pulp, involved in removing old blood cells, and a white pulp of lymphoid cells that respond to Ags delivered by the blood.

Answer 81

the spleen

Question 82

a subset of lymphocytes defined by their development in the thymus and by expression of the CD3 complex.

Answer 82

T cells, or T lymphocytes

Question 83

the deliberate induction of adaptive immunity to a pathogen by injecting a vaccine, a dead or attenuated (non-pathogenic) form of the pathogen.

Answer 83

Vaccination