Immunology Definitions

Front 1

Adjuvant

Back 1

carrier substances added to antigens in a vaccine to enhance the immune response

Front 2

Anergy

Back 2

state of unresponsiveness when T cell encounters antigen but no costimulatory signal

Front 3

Avidity

Back 3

number of binding sites for an antigen per antibody molecule

Front 4

B7

Back 4

costimulatory molecule on B cells needed for full T cell activation

Front 5

BCR/ TCR

Back 5

B/T cell receptor on cell surface – binds antigen or antigen fragments

Front 6

Blast

Back 6

activated T cell

Front 7

CD3

Back 7

TCR

Front 8

CD4

Back 8

marker for TH cells

Front 9

CD8

Back 9

marker for Tc cells

Front 10

CD28

Back 10

Costimulatory molecule on T cells needed for full activation which binds B7

Front 11

CD40/ L

Back 11

proteins on B and T cells which provide costimulation to B cells to aid antibody production

Front 12

Cell mediated immunity

Back 12

-T cell mediated responses

Front 13

Class switching

Back 13

change of constant region of antibody to direct location and function (eg IgM to IgE)

Front 14

Costimulation

Back 14

second stimulatory signal required by T and B cells to ensure full activation

Front 15

CTLA-4

Back 15

protein expressed by T cells to dampen down response

Front 16

Dendritic cells

Back 16

anigen presenting cells which phagocytose antigens, digest and carry and present fragments to T cells in lymph nodes

Front 17

Defensins

Back 17

chemicals produced by epithelial surfaces to kill off pathogens to prevent entry to body. Broad range weak antibiotics

Front 18

Effector cells

Back 18

Cells which remove pathogen through phagocytosis, cellular cytotoxicity

Front 19

Epitope

Back 19

part of antigen which is bound by and activates B cells

Front 20

Extravasation

Back 20

process by which white blood cells leave blood vessels and enter tissues

Front 21

FcR

Back 21

receptor on B cells which binds constant region of antibody to dampen down B cell activation or cause mast cell degranulation

Front 22

Gene recombination

Back 22

ability to mix and match different gene alleles to produce wide range of TCR/ antibodies

Front 23

Heavy chain

Back 23

part of antibody which includes constant alleles to determine antibody class

Front 24

HLA

Back 24

human leucocyte antigens –encode for MHC

Front 25

Humoral immunity

Back 25

antibody mediated responses

Front 26

Hypervariable regions

Back 26

amino acids within variable region that make specific binding contact with the antigen

Front 27

IL-1

Back 27

pro-inflammatory cytokine released by macrophages

Front 28

IL-4,5

Back 28

cytokines produced by TH2 cells to aid B cell activation

Front 29

Immune deficiency

Back 29

failure of immune system to be activated by pathogens

Front 30

Innate

Back 30

- in built from birth, basic first line defence, conserved in invertebrates up to mammals

Front 31

Invariant chain

Back 31

peptide bound in class II MHC to prevent presentation of self antigens

Front 32

Light Chain

Back 32

part of antibody lambda or kappa forms

Front 33

LPS

Back 33

lipopolysaccharide – constituent of gram negative bacterial cell walls –very potent at inducing immune system activation

Front 34

Lymph nodes

Back 34

organs where lymphocytes collect to wait for antigen

Front 35

Lymphocyte repertoire

Back 35

range of TCR/ antibodies which can recognise different foreign antigens

Front 36

Natural Killer cells

Back 36

lymphocyte-like cells. Activated to kill virally infected (self) cells

Front 37

Macrophage

Back 37

phagocytic cell producer of IL-1 and TNF to enhance immune response

Front 38

Mast cells

Back 38

white blood cells involved in acute inflammation and allergy due to release of histamine

Front 39

Memory

Back 39

Ability of immune system to respond quicker on second encounter. Mediated by B cells

Front 40

MHC

Back 40

Major histocompatibility Complex – proteins on the surface of our own cells which mediate antigen presentation (cf class I – all cells present to Tc and class II only on APCs present to Th))

Front 41

Monoclonal

Back 41

antibodies of a single specificity produced by one B cell and its daughter cells (cf polyclonal)

Front 42

Negative selection

Back 42

T cells which recognise self MHC/ ag too strongly are signalled to die in thymus

Front 43

Neutrophils

Back 43

phagocytic cells, lobed nucleus usually first at scene of infection

Front 44

Opsonins

Back 44

proteins which attach to microbes to enhance phagocytosis (see antibodies and complement)

Front 45

Passive immunity

Back 45

acquired immunity usually through maternal antibodies or antibody injection

Front 46

Pattern Recognition receptors

Back 46

– receptors on surface of macrophages, neutrophils, NK and Dendritic cells which recognise microbe specific surface markers eg mannose, LPS

Front 47

Plasma cells

Back 47

mature activated antibody producing B cells

Front 48

Phagocytosis

Back 48

process by which macrophages and neutrophils engulf and digest microbes

Front 49

Polyclonal

Back 49

range of antibodies produced by different B cells against the same antigen

Front 50

Positive selection

Back 50

only T cells which can recognise self MHC and antigen in thymus survive – non binding T cells die (cf negative selection)

Front 51

ROS

Back 51

reactive oxygen species (superoxide, hydrogen peroxide) which can cause microbe/cell damage and lysis

Front 52

Somatic hypermutation

Back 52

increase in binding affinity of antibody due to mutations in sequence of hypervariable region

Front 53

TC

Back 53

cytotoxic T cells – kill virally infected self cells

Front 54

TH

Back 54

Helper T cell- TH1 provides stimulation macrophages and Tc, Th2 provide costimulation to B cells to aid antibody production

Front 55

T reg

Back 55

regulatory T cells – dampen down immune response by inhibiting T cell activation

Front 56

Thymus

Back 56

primary lymphoid organ where T cells mature and undergo selection

Front 57

TNFa

Back 57

pro-inflammatory cytokine released by macrophages

Front 58

Tolerance

Back 58

ability of the body to ignore self antigens

Front 59

Vaccination

Back 59

use of heat killed/ non pathogenic forms of microbes to activate the immune system to induce memory cells allowing rapid response on re-encounter of the disease

Front 60

V,D,J,C

Back 60

Regions of antibody –variable, diversity (heavy chain only), Joining and Constant

Front 61

Zymogens

Back 61

proteins that gain enzymatic function through intramolecular cleavage