Keywords

Question 1

Adaptive immunity

Answer 1

immune respones mediated by lymphocytes and their products, requiring activation by innate immune mechanisms on first encounter with antigen but the lymphocytes act immediately on subsequent encounters

Question 2

Afferent lymphocytes

Answer 2

Lymphatic vessels entering lymph nodes from tissue spaces

Question 3

Affinity

Answer 3

Strength of a noncovalent binding reaction; the higher the affinty, the more likely two partners will exist in a complex

Question 4

Alveolar macrophages

Answer 4

Macrophages in the lung

Question 5

Antibodies

Answer 5

Highly variable proteins produced by B lymphocytes of the immune system and that recognise antigen and target it for destruction

Question 6

Antibody-dependanr cellular cytotoxicity (ADCC)

Answer 6

A process whereby FcR-bearing cells encounter an antibody-coated target cell and degranulate, releasing contents that kill the antibody- coated cell

Question 7

Antigen

Answer 7

any molecule or part of a molecule recognised by the variable antigen receptors of the lymphocytes.

Question 8

Antigenic drift (of influenza virus)

Answer 8

point mutations, predominantly in hemagglutinin and neuraminidase, that affect recognition by neutralizing human antibodies. Antigenic drift gives rise to epidemic infections.

Question 9

Antigenic shift (of influenza virus)

Answer 9

Reassortment of independent RNA segments from two different influenza genomes to generate recombinant virus with new antigenic subtypes. Antigenic shift gives rise to pandemic outbreaks.

Question 10

Antigen variation (in parasites)

Answer 10

clonal expression of members of proteins among parasite progeny; examples include the major surface glycoproteins of trypanosomes and the red cell adhesins encoded by maleria parasites; variant expression allows parasites to evade immune recognition

Question 11

Antigen presentation

Answer 11

The binding of fragments of intracellular molecules, usually peptides derived from proteins of pathogens, bu major surface histocompatibilty complex (MHC) molcules and their presentation on the cell surface for recognition of T cells

Question 12

Antigen-presneting cells

Answer 12

cells capable of displaying antigen for recogniton by T-cells and of activating naive T cells

Question 13

Antimicrobial peptides

Answer 13

peptide antibodies that provide defence against microbes and viruses by interacting with membranes of infectious agents and increasing their permeability. Homan antimicrobial peptides are members of either the alpha-defensin, beta-defensin or cathelicidin families

Question 14

Attenuation (of a pathogen)

Answer 14

Loss of pathogenicity, usually through adaptation to growth in culture in adverse conditions or in cells from a species other than that of the normal host. Attenuated pathogens are the basis of many vaccines

Question 15

Avidity

Answer 15

Increased apparent affinity of a molecule for its ligand due to the presence of multiple binding sites on both partners

Question 16

Basophils

Answer 16

circulating myeloid lineage cells that ar e characterised by cytoplasmic granules that stain with basic dyes and conatin inflammatory mediators and are believed to be important in defence against parasites as well as in inflammatory and allergic reactions

Question 17

C1q

Answer 17

complement component that binds to antibodies in immune complexes and activates the classical pathway of complement activation. In additon to activating the complement cascade, C1q is recognised by a phagocytic receptor of macrophages (C1qRp) and so can mediate phagocytosis directly.

Question 18

C3 convertase

Answer 18

either of two proteolytic enzymes of the complemtne ystsem that clease C3 to generate C3a and C3b. The C3 convertase of the classical and lectin pathways is a complex of C4b and C2b whereas the C3 converatse of the alternative pathway is a complex of C3b and Bb

Question 19

Capsular polysaccharide

Answer 19

cell-surface polymers of repeating oligosaccharide units, usually linked though phosphodiester bonds, that form a capsule on the suface of many pathogenic bacteria and protect bacterial cells from recognition by phagocytes. For this reason the presence of a capsule is often associated with virulence

Question 20

Cathelicidins

Answer 20

family of cationic antimicrobial peptides generated in pre-pro forms that require processing to generate the active peptide; cathelicidins contain an aimo-terminal cathelin-like domain and a carboxy terminal antimicrobial domain

Question 21

Chemokine

Answer 21

any of a family of closely related small, basic cytokines whose main function is as chemoattractants (a substance that attracts motile cells. The name is a contraction of chemotactic cytokine

Question 22

Classical pathway

Answer 22

complement activation pathway through which antibody-antigen complexes trigger the complement cascade. This pathway is also activated by the pentraxins (class of pattern recognition receptors)

Question 23

Clonal detection/deletion

Answer 23

elimination of potentially self-reactive lymphocytes. Immature lymphocytes undergo programmed cell death after binding to antigen; in this way, cells that are bearing receptors that recognise self are deleted before they are capable of participating in immune responses. This is a major mechanism of immune tolerance

Question 24

Clonal expansion

Answer 24

the selective proliferation of mature naive lymphocytes that encounter antigen. Only those lymphocytes bearing receptors specifically recognising antigen are activated to proliferate and diffrentiate into effector cells

Question 25

Clonal selection

Answer 25

The process whereby potenially self reactive lymphocytes are eliminated during early development whereas mature lymphoctytes reognising non-self antigens are slectively expanded

Question 26

Cluster of diffrentiation (CD)

Answer 26

The basis of a system for identifying cell suface molecules of immune cells by the use of antibodies and in which each molecule is given a specific number prefixed by CD to form the basis of a systematic nomenclature. The term cluster reflects the fact that each molecule is usually recognised by a group, or cluster of antibodies; and the appearance of the molecules usually reflects different diffrentiated states of the cell, hence diffrentiation. Surface marker molecules of immune cells of different types and at different stages of differentiation or activation have been identified in this way and can be used to classify cells, or to follow their progress through development of their activation status

Question 27

Collectin

Answer 27

any of a family of structurally related, carbohydrate- recognising proteins of innate immunity, including mannose-binding lectin and surfactant proteins A and D

Question 28

Complement

Answer 28

serum proteins activated diretly or indirectly by conserved surface features of microorganisms, or by antibody, to destroy microorganisms or induce their destruction through a coordinated immune response including induction of inflammation, attraction of leukocytes, stimulation of phagocytosis and stimulation of antibody production

Question 29

Complementarity-determining region (CDR)

Answer 29

region of a lymphocyte receptor for antigen that participates in the antigen-binding site and determines its structural complementarity to the antigen

Question 30

Constant (C) domain

Answer 30

Ig-like domain of the type found in Ig constant regions

Question 31

Constant region (C region)

Answer 31

Region of lymphocyte receptor for antigen that does not participate in antigen binding and does not vary between cells of different antigen specifcities

Question 32

Co-receptor (of T lymphocytes)

Answer 32

Receptor on a T cell that recognises invarient parts of the MHC molecules and forms a recognition complex with the antigen receptor and contributes to intracellular signalling

Question 33

Corticosteroids

Answer 33

natural and synthetic hormones that bind to and activate the glucocorticoid receptor. Corticosteroids are very effective antiinflammatory drugs and are aslo immunosuppressive

Question 34

Gram negative bacteria

Answer 34

single thin layer of peptidoglycan. periplasmic space between PM and peptidoglycan. An outer membrane external to the peptidoglycan which is covered by LPS (lipopolysaccharide). LPS components are lipid A and O antigen.

Question 35

Gram positive bacteria

Answer 35

thick layer of peptidoglycan to make up cell wall.

Question 36

formyl-methinoyl-leucyl-phenylalanine (fMLP)

Answer 36

it is a bacterial peptide that is a chemoattractant that activates neutrophils and macrophages. It directs the transport of secreted proteins that possess NH2-terminal signal peptides

Question 37

hybridoma cell

Answer 37

long-lving cells that produce specific antibody. IT has hypoxanthine guanine phosphoribosyl transferase (HGPRT) from the spleen B cell and immortality from the myeloma cell and can therefore grow in the Hat medium.

Question 38

Monoclonal antibodies

Answer 38

Specific antibody that binds to a specific antigen thta is produced by a single diffrentiated B cell

Question 39

polyclonal antibodies

Answer 39

many different B cells producing many types of antibodies

Question 40

calreticulin

Answer 40

signalling molecule that is expressed on cancerous cells that have unfolded proteins

Question 41

Rituximab

Answer 41

the first monoclonal antibody treatment approved for cancer. It is a chimeric human-mouse mAb targeted against CD20 ( an antigen present on the suface of neoplastic B cells)

Question 42

Herceptin

Answer 42

a humanised monoclonal antibody that blocks attachment of human epidermal growth factor to HER2 on breast cancer cells