7 - Antibodies in Immunity

Question 1

What is acquired immunological tolerance?

Answer 1

Continuous presence of non-self antigen before the immune system is fully developed leads to a permanent unresponsiveness to the non self antigen (induced antigen specific immunological unresponsiveness)

Question 2

What is the reticuloendothelial system

Answer 2

Part of the immune system that consists of phagocytic cells in connective tissue

Question 3

Are all secondary lymphoid organs independent

Answer 3

no. They are all connected by BVs and lymphatics. If you get a response at one then the effectors and the memory is distributed throughout the lymphatic tissue

Question 4

What do BVs and lymphatics bring in and out

Answer 4

Bring in CELLS (WBCs) and antigen and take out effectors/antibodies/lymphocytes

Question 5

How do APCs present epitopes

Answer 5

Major Histocompatability Complexes (MHC proteins)

Question 6

What does node swelling usually indicate?

Answer 6

An immune response

Question 7

What does the response of the IS to a foreign substance depend on?

Answer 7

Route and nature of the foreign substance i.e. non-infectious and infectious material are NOT treated the same

Question 8

What does foreign material usually first encounter

Answer 8

Phagocytic cells of the reticuloendothelial system

Question 9

What occurs in the secondary lymphoid organs

Answer 9

the APCs (specialised localised phagocytes) present antigen via the major histocompatability complexes (MHC molecules) to lymphocytes with specific compatible/high specificity receptors

Question 10

What can the lymphocytes be classified into based on function

Answer 10

Effectors and regulators

Question 11

Effectors

Answer 11

• antigen-dependent cell mediated cytotoxicity (K cells)
• antigen specific cytotoxicity ( CD8 T cells)
• B cells (antibodies)
• NK cells

Question 12

Regulators

Answer 12

• Th cells
• regulator t cells
• CD4 T cells (cytokines)

Question 13

What are the 3 types of shape recognition

Answer 13

1. Common characteristic to many substances (non-specific immunity bacterial cell wall sugar)
2. Unique characteristic of a particular foreign substance (specific immunity i.e. viral capsid protein)
3. Common but in an uncommon context i.e. myocardium shapes on a streptococcal bacteria)

Question 14

Innocuos Antigen

Answer 14

Shapes on things that are not harmful to us. In allergy/hypersensitive response the IS overreacts to the innocuous shapes we shouldn’t be responding to. Occurs especially when we breather it in or ingest it (epithelial surfaces) i.e. dust or pollen

Question 15

What cells recognise a change in our cells i.w. tumour cells, virus infected or cancer cells

Answer 15

natural killer cells

Question 16

What lymphocytes produce cytokines

Answer 16

CD4 T cells

Question 17

CD8 cells?

Answer 17

Antigen specific cytotoxic cells

Question 18

Do all lymphocytes have receptors?

Answer 18

Yes and all are antigen specific

Question 19

What triggers differentiation of the pluripotent haemopoetic stem cells

Answer 19

hormonal influences usually to b driven along particular pathways when we need specific cells

Question 20

What is the receptor on a B cell called

Answer 20

Like an antibody shape anchored into the membrane - surface immunoglobulin (sIg)

Question 21

What is the receptor on a T cell

Answer 21

T cell receptor TCR

Question 22

What are associated with the receptors on lymphocytes

Answer 22

Pointing out and recognising outside world - when bind need to send signal into cell. Receptors have signal transduction transmembrane molecules associated with them

Question 23

Transmembrane molecule on B and T cells?

Answer 23

T cells - CD3 signal transduction molecule

B cells - CD79 signal transduction molecule

Question 24

What is CD3 present on

Answer 24

ALL T cells (important in blood count)

Question 25

How does lymphocyte response work

Answer 25

Antigen specific binding leads to changes in receptors that is transmitted into the cell creating a signal leading to a change in cellular activity i.e. diferentiation into antibody forming cells, helper or cytotoxic cells, or division

Question 26

What does # of CD3 molecules tell you

Answer 26

number of t cells (both CD4 and CD8 have CD3)

Question 27

What do B and T cells respond to

Answer 27

B cell can be free antigen or presented antigen

T cell HAS to be presenTed antigen

Question 28

What are antibodies

Answer 28

Glycoprotein molecules
Made of 4 polypeptide chains
2 are identical and short (light chains)
2 are identical and bigger (heavy chains)
Forms globular protein held together by disulphide bonds

Question 29

antibody structure

Answer 29

In the light chains 1/2 aa’s are identical in antibodies i.e. Constant
Other half is highly variable AAs i.e. variable region
In heavy chains, 3/4 is constant 1/4 (constant region of heavy chain/domains) is variable

Question 30

What is in the middle of the heavy chain?

Answer 30

Hinge region

Region of AAs that allow arms of anibody to be flexible

Question 31

What makes up the antigen binding site

Answer 31

The variable regions of both the heavy and light chains

There are regions of hypervariablity in these (fingers that can grab antigenic epitope)

Question 32

What is special about the CH2 domain of the heavy chain

Answer 32

CH2 binds complement proteins (complement binding region) when antibody has a particular shape

Question 33

What is special about the CH3 doman

Answer 33

From hinge region down is the Fc region (can crystallise)

But ALSO is recognised strongly by receptors on neutrophils and enhances phagocytosis

Question 34

What percent of blood proteins do antibodies/Igs make up

Answer 34

1%

Question 35

What are the 4 pp chains held together by

Answer 35

Disulphide bonds and non-covalent interactions

Question 36

When can complement proteins bind to CH2 of the heavy chain

Answer 36

Only when the antibody s bound to antigen

Question 37

Example of a primary response

Answer 37

Vaccination