Immunology Physiology: Part 2

Question 1

What are MHCs?

Answer 1

Protein molecules (self-antigens) on the surface of cells. They help differentiate between invaders and self

• unique to an individual
• useful in matching organ donors

Question 2

Where are MHC Is found?

Answer 2

found on virtually all body cells (except for red cells)

Question 3

Where are MHC II’s found?

Answer 3

found on certain cells in the immune response

Question 4

What do MHCs display?

Answer 4

peptides, usually self antigens

Question 5

What do MHC’s display in infected cells?

Answer 5

display fragments of foreign antigens, which help mobilize Tcells

Question 6

What are B lymphocytes associated with?

Answer 6

(B cells)—humoral immunity

Question 7

What are T lymphoctyes associated with?

Answer 7

(T cells)—cell-mediated immunity

Question 8

Where is the bone marrow do lymphocytes develop?

Answer 8

shafts of long bone and vertebra

Question 9

When lymphocytes mature what characteristics do they posess that make them functional?
2

Answer 9

1. Immunocompetence– they are able to recognize and bind to a specific antigen
2. Self-tolerance – unresponsive to self antigens

Question 10

Where are naive (unexposed) lymphocytes exported to?

3

Answer 10

lymph nodes
spleen
other lympoid organs

Question 11

What are peyer’s patches?

Answer 11

Fixed macrophages in the colon

Question 12

What are the major types of APC’s?

3

Answer 12

1. dendritic cells
2. macrophages
3. activated B cells

Question 13

Where do T cells become immunocompetent?

B cells?

Answer 13

thymus

bone marrow

Question 14

Antigen-activated immumocompetent lymphocytes are what kind of cells?

Answer 14

effector cells and memory cells

Question 15

What is positive selection of a T cell?

Answer 15

Selects T cells capable of binding to self-MHC proteins (MHC restriction)

Question 16

What is negative selection of T cells?

What does this ensure?

Answer 16

Prompts apoptosis of T cells that bind to self-antigens displayed by self-MHC

Ensures self-tolerance

Question 17

What will happen if a B cell is self-reactive?

3 things can happen

Answer 17

1. Are eliminated by apoptosis (clonal deletion-group of cells that are related are deleted) or
2. Undergo receptor editing – rearrangement of their receptors
3. Are inactivated if they escape from the bone marrow

Question 18

What determines which foreign substances the immune system will recognize and resist?

Answer 18

Genes

Question 19

Macrophages as APCs are mostly found where?

Answer 19

Fixed in the lymphoid organs

Question 20

Dedritic cells as APCs are mostly found where?

Answer 20

internalize pathogens and enter lymph system to present antigens to lymphoid organs

Question 21

How do T cells activate macrophages?

Answer 21

release chemicals that make them insatiable phagocytes and secrete bactericidal chemicals

Question 22

If the anitgen provokes a humoral immune response what is produced?

Answer 22

antibodies

Question 23

In clonal selection how do the daughter cells differentiate from the parent cell?

Answer 23

Through chances in DNA that have different receptor that will indentify a uniquely different pathogen

Question 24

Do B cells need MHC proteins/APC?

Answer 24

No, they can bind directly to the antigen

Question 25

After the B and T cells are selected for by the antigen what happens?

Answer 25

They begin replicating rapidly but with the same receptor (unlike the first round)

Question 26

When the B cells and T cells are replicating to mount an immune response to the antigen they encoutnered what kind of cells do they make?

Answer 26

Effector cells (plasma cells)- used to fiight the pathogen right now! -this is the fate of most cells Memory cells- used to remember the pathogen and mount/signal an even stronger/faster response next time

Question 27

What do effector cells do to mount an immune response?

Answer 27

secrete antibodies at a rat eof 2000 per second fro 4-5 days

Question 28

What are the antibodies doing in the body?

Answer 28

circulating in blood an dlymph and marking the antigens for destruction

Question 29

Whats the lag period of the primary immune response (first time the body ever encounters an antigen?) When are peak levels of antibodies reached?

Answer 29

three to 6 days 10 days then anitbody levels decline

Question 30

Whats the lag period of the secondary immune respnse? Anitbody levels peak when?

Answer 30

hours two to three days. Anitbodies bind with greater affinity and remain high for weeks or months

Question 31

What are the two types of active humoral immunity and give an example of each

Answer 31

1. Naturally acquired—response to a bacterial or viral infection 2. Artificially acquired—response to a vaccine of dead or attenuated pathogens

Question 32

Why do vaccines fail to fully establish cellular immunological memory?

Answer 32

They only target one type of helper T cell

Question 33

What is different about passive humoral immunity compared to active?2

Answer 33

1. B cells are not challenged by antigens | 2. Immunological memory does not occur

Question 34

What are the two types of passive humoral immunity and give an example

Answer 34

1. Naturally acquired—antibodies delivered to a fetus via the placenta or to infant through milk 2. Artificially acquired—injection of serum, such as gamma globulin - -Protection is immediate but ends when antibodies naturally degrade in the body

Question 35

What are immunoglobulins? | 2

Answer 35

1. Proteins secreted by plasma cells | 2. Capable of binding specifically with antigen detected by B cells

Question 36

What is the general structure of an antibody?

Answer 36

two heavy chains and two light chains

Question 37

What part of the antibody structure determines the antibody class, what the antibody can bind to, and how the antibody functions in antigen elimination?

Answer 37

Constant (C) region of stem

Question 38

Characteristics of IgM? | 2

Answer 38

first responder to acute infection (can be a monomer-pentamer in pic)

Question 39

Characteristics of IgA? | 2

Answer 39

1. Helps prevent attachment of pathogens to epithelial cells/respiratory too - because its found in body secretions 2. (dimer)

Question 40

Characteristics of IgD | 2

Answer 40

Anitgen receptor for B cells | Monomer

Question 41

Characteristics of IgG | 4

Answer 41

1. Most abundant and diverse antibody in plasma 2. Main antibody in primary and secondary respinses 3. Passes from mother to fetus 4. monomer

Question 42

Characteristics of IgE | 3

Answer 42

1. Causes release of histamines 2. Heightened in allergic reactions 3. monomer

Question 43

Antibodies inactivate and tag antigens

Answer 43

Statement

Question 44

What is neutralization?

Answer 44

antibodies bind to and block specific sites on viruses or exotoxins, thus preventing these antigens from binding to receptors on tissue cells

Question 45

What is aggulation?

Answer 45

1. antibodies bind the same determinant on more than one antigen 2. Makes antigen-antibody complexes that are cross-linked into large lattices - -Cell-bound antigens are cross-linked, causing agglutination

Question 46

What is precipitation?

Answer 46

soluble molecules are cross-linked into large insoluble complexes --more subjectable to phagocytosis

Question 47

What is complement fixation?

Answer 47

1. cell lysis and activation of phagocytosis - The MAIN mechanism used against cellular antigens - Enhances the inflammatory response

Question 48

What are monoclonal antibodies made of?

Answer 48

hybridomas | Cell hybrids: fusion of a tumor cell and a B cell

Question 49

What could monoclonal antibodies be useful for?

Answer 49

Proliferate indefinitely and have the ability to produce a single type of antibody Used in research, clinical testing, and cancer treatment

Question 50

What kind of cells are involved un cell-mediated immunity?

Answer 50

T cells and CD4 and 8 cells

Question 51

When activated what do CD4 T cells become?

Answer 51

Helper T cells

Question 52

When activated what do CD8 cells become?

Answer 52

cytotoxic T cells

Question 53

What do antibodies of the humoral response target?

Answer 53

Bacteria and molecules in intracellular environments (body secretions, tissue fluid, blood and lymph) Straight for pathogen

Question 54

What do T cells of cellmediated response target? | 3

Answer 54

1. Body cells infected by viruses or bacteria 2. Abnormal or cancerous cells 3. Cells of infused or transplanted foreign tissue Cells that are infected by pathogen

Question 55

Endogenous antgens are processed and displayed by what?

Answer 55

Class I MHC proteins

Question 56

Exogenous antigens are processed and displayed by what?

Answer 56

Class II MHC proteins

Question 57

What two things have to happen for a T cell to be activated?

Answer 57

1. Antigen binding | 2. Co-stimualtion

Question 58

How are dendritic cells able to obtain other cell's endogenous antigens? 2

Answer 58

1. Engulfing dying virus-infected or tumor cells | 2. Importing antigens through temporary gap junctions with infected cells