Everything there ever was Lecture 5-8

Question 1

How are macrophages activated?

Answer 1

LPS (TLR4) and IFN-gamma

Question 2

What are the cytokines that act locally on the endothelial tissues?

Answer 2

TNF and IL-6

Question 3

Which 3 cytokines are involved in the protective systemic effects including fever, APP synthesis in the liver, and leukocytosis in the bone marrow?

Answer 3

TNF
IL-1
IL-6

Question 4

What results physiologically if there is an increase in the systemic TNF?

Answer 4

decreased cardiac function
thrombosis
insulin resistance

Question 5

What are the functions of CRP and SAP and when do their levels increase?

Answer 5

They are acute phase proteins (APPs) that are synthesized int eh liver after an alert from IL-1 and IL-6; they recognize phospholcholine and phosphatidylethanolamine which are in bacteria and apoptotic cells

They can activate the complement pathway (classical) via C1q activation

Question 6

When are IFN alpha and beta made and why are they made?

Answer 6

They are made to bind to the infected cells (self) and enhance cell mediated killing

They can also be made by the infected cells to go an initiate the JAK stat pathways in the neighboring cells which induces the expression of genes whose products interfere with viral replication ( so the neighbors dont get sick I think)

Question 7

Describe the basic structure of an Ab

Answer 7

1. 4 chains; two light and two heavy that are divided into V and C regions
2. can be cleaved to form 2 fab and one fc fragment

Question 8

What does the V region on the Ab do? The C region?

Answer 8

V- Ag binding site

C- determines the fate of Ag

Question 9

Describe the breakdown of IgG when it is exposed to papain

Answer 9

2 separate Fab’s with one that is still joined to Fc

Question 10

Describe the break down of IgG when it is exposed to Pepsin

Answer 10

The Fc chain is degraded, and the 2 Fab remain fused so that they are able to bind Ags

Question 11

Describe antibody affinity and explain the differences between primary responses and memory responses

Answer 11

affinity is the tightness of the bond between the Ag and the Ab, a primary response has a lower affinity and the memory response has a higher affinity

valence is important for affinity because having more binding sites will result in tighter bonds

Question 12

Define avidity

Answer 12

measure of the strength of an Ab-Ag complex

Depends on: affinity of the Ab for the epitope and the valence of the Ab and the Ag

Question 13

What are the Ab proliferation cytokines

Answer 13

IL-2, IL-4, IL-5

Question 14

What are the Ab differentiation cytokines?

Answer 14

IL-2, IL-4, IL_5, IFN gamma and TGF beta

Question 15

What happens on the V region of the antibody?

Answer 15

Antibody recognition

Question 16

What happens on the C region of the antibody?

Answer 16

determines the fate of the Ag

Question 17

What happens when IgG is exposed to papain?

Answer 17

the 2 Fab’s separate with one still being joined to the Fc region

Question 18

What happens when the IgG is exposed to pepsin?

Answer 18

The Fc region is disintegrated

Question 19

What happens to the Ab when there is a high Ka?

Answer 19

It is less likely to give up the ag

Question 20

Describe IgG

Answer 20

It is the most abundant in the blood and provides immunity against blood bourne pathogens

ONLY one to cross the placenta

Question 21

Describe IgD

Answer 21

-low quant in the circulation

It is an Ag receptor and helps initiate the humoral response

Question 22

Describe IgM

Answer 22

Acts as a BCR initially and is the main defense until the IgG is made

First ab produced

HIGH avidity

Question 23

Describe IgA

Answer 23

Mucous
involved in external secretions
-has two extra chains SC and J chain

-synthesized by plasma cells

Question 24

Describe IgE

Answer 24

low levels in the serum

• acute inflammation
• protects agains worms and allergic rxns

-binds to mast cell and promotes inflammation

Question 25

Which T cells are able to recognize Ags that are bound to the MHC class II molecules?

Answer 25

the Cd4 T helper cells bind to MHC II on DC’s

Question 26

Which T cells are able to recognize Ags that are bound to the MHC class I molecules?

Answer 26

Cd8 cytotoxic T cells

Question 27

What is the function of Th1?

Answer 27

help macrophages get rid of intracellular microbes

produces IFN gamma

Question 28

What is the function of Th2

Answer 28

help beta cells develop memory and plasma

produces IL-4 which leads to B cell proliferation

Question 29

Describe the Class I MHC pathway in detail

Answer 29

1. virus is present in the cytoplasm and starts making proteins
2. the proteins are ubiquinated and marked for degradation
3. proteasome comes in and degrades
4. the viral peptides travel to the ER and enter via the TAP (transporter associated with Ag processing)
5. ERAD binds to the viral peptide and delivers to the Class I MHC molecule which binds to B2m
6. class I MHC and the peptide travels to the Golgi to go to exocytosis
7. CD8 comes and grabs the ish and takes it to initiate a response

Question 30

Describe the Class II MHC pathway in detail

Answer 30

1. uptake of the extracellular proteins via endocytosis
2. the endosome forms with the lysosome to form the endolysosomal vesicle and the protein is degraded
   MEANWHILE…..
   ER is making Class 2 molecules, which are combined with an endosome that travels to the Golgi
3. the endosome that is carrying the class II MHC binds with the endosome that has the peptides
4. MHC II grabs the peptides and takes them to the cell surface
5. CD4 recognizes and takes it to make an immune response

Question 31

What is the function of HLA-DM?

Answer 31

editing mechanism that makes sure that the proteins are presented to the correct cells that are able to initiate an immune response

Question 32

What are the 3 functions of the HLA-DM?

Answer 32

1. dissociation of CLIP from the peptide binding groove of MHC class II
2. prevents the degradation of MHC II
3. facilitates the binding of the Ag fragments