adaptive

Question 1

what is adaptive immunity?

Answer 1

is the third line of defence that recognises pathogens and eradicates them

Question 2

what are the three advantages of adaptive immunity?

Answer 2

• precise targeting
• memorising cells
• recognise new pathogens

Question 3

what type of cells are important in adaptive immunity

Answer 3

b cells
t cells

Question 4

where are b cells formed and mature

Answer 4

cells are formed and mature in the bone marrow

Question 5

where are t cells formed and mature?

Answer 5

formed in the bone marrow and mature in the thymus

Question 6

why are lymphocyte receptors unique?

Answer 6

receptors are made by gene rearrangement so we all have unique clones of various receptors

Question 7

b cell receptors

Answer 7

b cell receptors have two light chains and two heavy chains

Question 8

t cell receptors

Answer 8

t cell receptors have an alpha chain and a beta chain

Question 9

what is clonal expansion?

Answer 9

clonal expansion is when pathogen-reactive lymphocytes are triggered to divide and proliferate

Question 10

describe adaptive immunity

Answer 10

• dendritic cells carry antigens to the lymph node and stimulate adaptive immunity.
• pathogen is taken apart inside dendritic cells where pathogen proteins are unfolded and cut into pieces (antigen processing)
• the peptides bind to MHC molecules and the complexes go to the cell surface
  _ t cell receptors bind to peptides = MHC complexes on dendritic cell surface (antigen-presenting )

Question 11

major histocompatibility complex (MCH) is also known as ..

Answer 11

human leukocyte antigen

Question 12

two types of MHC

Answer 12

one and two

Question 13

what MHC I binds to what t-cell population

Answer 13

CD8 T CELL (CYTOTOXIC)

Question 14

what MHC II binds to what t-cell population

Answer 14

CD4 T CELL( HELPER)

Question 15

MHC one is only presented on

Answer 15

nucleated cells

Question 16

MHC two is only presented on

Question 17

MCH I presents

Answer 17

when viral proteins synthesise in cytoplasm
peptide fragments of viral proteins bound by MHC class I in ER
bound proteins are transported by MHC I to the cell surface
Cytotoxic T cells recognise the viral peptide and MHC I and kills infected cells

Question 18

MCH II presents Ag

Answer 18

macrophages engulf and degrades bacterium producing peptides
bacterial peptides bound by MHC II in vesicles
Bound peptides transported by MHC II to cell surface
helper t cell recognise peptide antigens and MHC nad activates macrophages

Question 19

what do b cells recognise

Answer 19

native antigens

Question 20

explain b cell multifunctional properties

Answer 20

• use highly specific receptors and antibodies
• act as antigen presenting cells

Question 21

describe how b cells become antigen-presenting cells

Answer 21

-cell surface immunoglobulin of b cells binds to bacteria: cell engulfs and degrades them producing peptides.
-bacteria peptides bound by MHC 2 in endocytic vesicles
-bound [peptide transported by MHC 2 to the cell surface
-helper t-cells recognise complex peptide antigens with MHC 2 and activate b cell

Question 22

what are antibodies

Answer 22

soluble effector molecules of adaptive immunity

Question 23

what are the five isotypes of antibodies

Answer 23

IgA, IgG, IgM, IgE, IgD

Question 24

what are the main antibodies? found in the blood, lymph and tissue fluid

Answer 24

IgA, IgG and IgM

Question 25

what is the first antibody made in the primary immune response

Answer 25

IgM

Question 26

What antibody is found at the mucosal surface

Answer 26

IgA

Question 27

what acronym is used to remember the antibodies

Answer 27

GAMED

Question 28

How do antibodies respond to bacterial toxins

Answer 28

by neutralising toxins by binding to toxins

Question 29

How do antibodies respond to bacteria in the extracellular space

Answer 29

by opsonization where antibodies bind to bacteria (with complement) and are then engulfed by macrophages

Question 30

do Antibodies act as molecular flags for pathogen clearance

Answer 30

yes which causes the ingestion and destruction by phagocytosis

Question 31

explain how Antibodies improve over the course of an infection

Answer 31

(ex. IgM) is the first released antibody made against infecting pathogens. Somatic hypermutation selects antibodies that bind more tightly to the pathogen. Switching antibody isotype to IgG allows delivery of pathogen to phagocytes.

Question 32

when are memory cells produced

Answer 32

During primary infection, clonal expansion produces effector cells and memory cells

Question 33

how do Memory cells make even better responses

Answer 33

• more numerous than the original clone
• more quickly activated than the original clone
• Memory T cells patrol lymphoid tissue to detect infection early
• Memory B cells make better immunoglobulins:
• Already somatically mutated
• Already class-switched

Question 34

what is tolerance

Answer 34

Tolerance is the process of clearing self-reactive cells

Question 35

what is central tolerance

Answer 35

T cells undergo negative and positive selection in the thymus

Question 36

are lymphocytes self tolerant

Answer 36

yes

Question 37

what are the disadvantages of adaptive immunity

Answer 37

resulting in chronic, non-infectious conditions:
Autoimmunity (e.g. rheumatoid)
Allergy and hypersensitivity (e.g. asthma)

Transplanted organ/tissue is non-self, and is quite rightly attacked as such

Cells of the adaptive immune system are targets of some viruses, which can cause problems later (HIV infects CD4+ T cells, Epstein-Barr virus infects B cells)

Question 38

describe an auto-immunity example of a disadvantage of adaptive immunity

Answer 38

Question 39

describe an allergy and hypersensitivity example of a disadvantage of adaptive immunity

Answer 39