Lecture 13

Question 1

All our cells have

Answer 1

unique surface markers (1000s molecules)

Question 2

MHC-I molecules are built into

Answer 2

cell membrane of all cells except red blood cells

Question 3

MHC-II markers seen only on

Answer 3

membrane of antigen presenting cells (macrophages, B cells, thymus cells)

Question 4

Function of complex antigens:

Answer 4

• T cells recognize is problem

- will display as part of their MHC-II

Question 5

Pathways of Antigen Processing:

Answer 5

• B and T cells must recognize a foreign antigen before beginning their immune response
• B cells can bind to antigen in extracellular fluid
• T cells can only recognize fragments of antigens

Question 6

Foreign antigen in body fluid is phagocytized by

Answer 6

APC

Question 7

Antigen is digested and fragments are

Answer 7

bound to MHC-II molecules stuck into antigen presenting cell membrane

Question 8

APC migrates to

Answer 8

lymphatic tissue to find T cells

Question 9

Cytokines & Cytokine Therapy:

Answer 9

1. Small protein hormones involved in immune responses

2. Cytokine therapy uses cytokines (interferon)

Question 10

Cell-Mediated Immunity:

Answer 10

Begins with activation of T cell by a specific antigen

Result is T cell capable of an immune attack

Question 11

Types of Mature T Cells

Answer 11

Helper T cells
Cytotoxic (killer) T cells
Memory T cells

Question 12

Helper T Cells:

Answer 12

1. Display CD4 on surface so also known as T4 cells or TH cells
2. Recognize antigen fragments associated with MHC-II molecules & activated by APCs
3. Function is to costimulate all other lymphocytes

Question 13

Cytotoxic T Cells:

Answer 13

1. Display CD8 on surface
2. Known as T8 or Tc or killer T cells
3. Recognize antigen fragments associated with MHC-I molecules
4. Costimulation required by cytokine from helper T cell

Question 14

Memory T Cells:

Answer 14

1. T cells from a clone that did not turn into cytotoxic T cells during a cell-mediated response
2. Available for swift response if a 2nd exposure should occur

Question 15

Antibody-Mediated Immunity:

Answer 15

• Millions of different B cells that can recognize different antigens and respond
• B cells sit still and let antigens be brought to them
• Once activated, differentiate into plasma cells that secrete antibodies
• Antibodies circulate in lymph and blood

Question 16

Antibody Classes:

Answer 16

IgG
IgM  
IgD 
IgA 
IgE

Question 17

IgG =

Answer 17

80% of plasma Ab’s, enhances phagocytosis, neutralizes viruses, protects newborn

Question 18

IgM =

Answer 18

10% of plasma Ab’s, first produced during infection, neutralizes bacteria, agglutinates

Question 19

IgD =

Answer 19

0.2% of plasma Ab’s, D = Don’t know

Question 20

IgA =

Answer 20

15% of plasma Ab’s, only mucosal surfaces

Question 21

IgE =

Answer 21

0.002% of plasma Ab’s, allergic reactions

Question 22

Immunological Memory:

Answer 22

• Primary immune response

- Secondary immune response with 2nd exposure

Question 23

Primary immune response:

Answer 23

first exposure to antigenresponse is steady, slow

memory cells may remain fordecades

Question 24

Secondary immune responsewith 2nd exposure

Answer 24

1000’s of memory cells proliferate & differentiate into plasma cells & cytotoxic T cells
recognition & removal occurs so quickly not even sick

Question 25

T cells must learn to recognize

Answer 25

self (its own MHC molecules ) & lack reactivity to own proteins

Question 26

T cells mature in thymus:

Answer 26

those can’t recognize self or react to it

same for b-cells