Lecture 4

Question 1

How are lymphocyte receptors formed?

Question 2

Lymphocytes most gain immunocompetence….

Answer 2

B cells are born in bone marrow and mature there
T cells are born in bone marrow but mature in Thymus
Variable region on receptro has a lot of genes encoding for it, VDJ segments
Cell choose V D and J segments
RAGs put these together to put together a possible combination of output
50 V genes
25 D genes
6 J genes
Gives you 10 000 combinations
This isn’t enough so we use TdT (terminal deoxynucleotidyl transferase)

Question 3

Primary response

Answer 3

Little bit of antibody

Question 4

Secondary response

Answer 4

Lots of antibody

Question 5

What’s prodcued first?

Answer 5

IgM produced first and are good at calling up compliement
BUT IgG are activated soon after and are made in larger quantities on second exposure and very useful cause they can move around wherever

Question 6

VDJC meaning

Answer 6

V- variable
D - diversity
J - joining
C - constant

Question 7

Self Antigents

Answer 7

Under normal circumstances the body will NOT create antibodies to self-antigens
MHC recognizes self, unique to each person except identical twins

Question 8

Immune tolerance

Answer 8

Delete or inactivate lymphocytes that have receptors that might recognize our own body antigens
Happens in fetal, in utero , in thymus for T-cell receptors

Question 9

How do we decide which T-cell to keep?

Answer 9

T cells must recognize MHC class II molecules
T cells should NOT recognize self-proteins, those expressing MHC Class - I molecules
if they do they will be destroyed

Question 10

95% of T cells will be destroyed

Answer 10

Bc they are self-reactive
Seems wasteful

We have billions of T-cells in the Secondary lymphoid organs with different TCRs that can recognize virtually any foreign material that may enter the body

Question 11

If bacteria divides more rapidly then we create antibodies we….

Answer 11

Get sick

Question 12

Memory Cells for B cells and T cells

Answer 12

Awesome, help us make stuff faster

Question 13

NK cells

Answer 13

Non-specific branch of immune system

Question 14

Cytotoxic T cell (CD8+)

Answer 14

Requires specific antgen recognition

Question 15

Endogenous Antigen

Answer 15

Cytotoxic T-cells need to recognize endogenous antigens
E.g infected body cell, virus uses it to make stuff, endogenous antigen
Presented using MHC class I molecules on infected body cells

Question 16

Exogenous Antigen

Answer 16

Antigen presented cells
MHC-II
Come from outside the nody

Question 17

Dendtritic cell binds to T-helper cell

Answer 17

Activates B and can activate Cytotoxic T -cell (cytokine release will do this)
Also needs to recognize specific antigen

Question 18

Also need to recognize the specific antigen

Answer 18

T-cell must have been stimulated by infected body cell with matching MHC I molecule on surface will lead to killing of infected body cell

Question 19

Release of granzymes and perforins

Answer 19

Kill infected cell

Question 20

Virus produced by cell

Answer 20

Virus fragments will be present with cells MHC class I molecules, this signals to body that your own body cell is infected

Question 21

Cytokine from activated helper T cell is needed to activate cytotoxic T cells

Answer 21

Yes

Question 22

CTLA4 means…

Answer 22

Stop T-cell activation

Question 23

Anti CTLA4

Answer 23

Harnesses power of T-cells to kill cancerous cells

Question 24

Protein-calorie malnutrition

Answer 24

greatest contributor to decreased resistance to infection worldwide

Question 25

Preexisting disease

Answer 25

Infectious or noninfectious, can predispose the body to infection

Question 26

Stress and state of mind

Question 27

Sleep deprivation

Question 28

Modest exercise and physical conditioning

Question 29

Immunodeficiency Diseases

Answer 29

SCID = lack of a cytokine necessary for development of lymphocytes (B and T cells) and even NK cells sometimes
AIDS - infects and kills helper T cells resulting in impaired immune responses to infectious organisms

Question 30

Harmful immune responses

Answer 30

Tissue Grafts and Organ Transplantation:
- diff between your MHC class I molecules and that of a donor won’t allow your body to take
- diff between MHC -II of you and donor, helper T cells are gonna activate cytotoxic T cells

Question 32

How to avoid graft rejection?

Answer 32

Radiation to eliminated dividing cells
Drugs that kill actively dividing lymphocytes (decrease recipients T-cell population)
E.g CYCLOSPORINE - blocks cytokine production from helper T cells to eliminate signals
unfortunately you will be susceptive to other diseases at this time.

Question 33

Transfusion reactions

Answer 33

Illness caused when erythrocytes are destroyed during blood transfusion
Only nucleated body cells have MHC class I
Erythrocytes dont have a nucleus so they dont have MHC class I proteins on their surace but they do have plasma and membrane proteins that can function as antigens

Question 34

Plasma membrane proteins and carbohydrates that function as antigens on erythrocytes….

Answer 34

ABO system of carbohydrates
Rh erythrocyte-membrane antigens

Question 35

Universal Donor

Answer 35

O

Question 36

Universal recipient

Answer 36

AB

Question 37

Rh factor

Answer 37

Negative or positive
If Rh antigen is on surface of red blood cells

Question 38

Allergic reaction

Answer 38

2 types:
immediate hypersentitivity
delayed hypersentitivity 12-72 hours after allergen exposure
Due to mast cells (filled with granules), if large release of histamine into blood stream…
ANAPHYLAXIS

Question 39

Anaphylaxis

Answer 39

Mast cell granules filled with histamine are released and cause Anaphylaxis
Not localized response like usual, response is of the whole body
Severe hypotensions and bronchiolar constriction

Question 40

Autoimmune disease

Answer 40

Inappropriate immune attack triggered by body proteins acting as antigens
e.g type 1 diabetes
rheumatoid arthiritis
multiple sclerosis
myasthenia gravis

Question 41

Regulatory T-cells dampen immune response…

Answer 41

Maybe can help fight autoimmune disease