Module 2: Lecture 6

Question 1

what are the two types of adaptive immunity?

Answer 1

1. humoral immune responses (or antibody-mediated) (where antibodies do their job)
2. cell-mediated immunity

Question 2

what do humoral mean?

Answer 2

in secretion

Question 3

which class of adaptive immunity involves the productive of antibodies in the lymph nodes by B lymphocyte derivatives known as plasma cells?

Answer 3

antibody-mediated / humoral immunity

Question 4

what is cell-mediated immunity?

Answer 4

• adaptive immunity
• involves production of activated T lymphocytes that directly attack unwanted cells

Question 5

what are antigens?

Answer 5

• large, foreign, unique complex molecule
• induces (elicits) an immune response against itself
• in general, the more complex a molecule is, the greater its antigenicity
• mostly protein in nature

Question 6

what is antigenicity?

Answer 6

the ability to induce immune responses

Question 7

in an antigen, the more protein and the more complex…..?

Answer 7

the more antigenicity

Question 8

can complex carbohydrates and complex lipids be an antigen?

Answer 8

yes

Question 9

why did we create the lymphatic system?

Answer 9

we needed a place where all the different lymphocytes go to check whether we have an infection or not

Question 10

lymphocytes are specific to what?

Answer 10

recognizing different antigens/pathogens

Question 11

how many B cells and T cells in our body?

Answer 11

hundreds of billions

Question 12

each B cell and T cell have different?

Answer 12

antigen receptor that sees a different antigen
- this gives them high specificity

Question 13

do all macrophages have different antigen receptors?

Answer 13

no, they have the same. they are very low specificity

Question 14

• what is clonal selection/expansion?

Answer 14

in adaptive immunity, all the B cells and T cells are different from eachother. so when a pathogen is brought to the lymphatic system, all the T and B cells check if its a match. when it is, THEN the B and T cells clone into many.

Question 15

why do we not have many of each T and B cell?

Answer 15

there are too many of each different kind. there would not be enough space. cloning happens where there is an invading pathogen

Question 16

what is immunological memory?

Answer 16

B and T cells form this
- the cells you were making to fight the pathogen and make those antibodies, they will set them aside as memory cells

Question 17

• which immunity is immunological memory?

Answer 17

acquired or protective immunity

Question 18

what do B lymphocytes do for adaptive immunity?

Answer 18

secrete antibodies
- B cell activation proliferation and differentiation of antigen-specific B cells that turn into plasma cells and then start making antibodies on site so that they can travel via the blood to the site of the infection

Question 19

what do the antibodies made from the B cells in adaptive immunity do once they reach the infection site?

Answer 19

• antibody binds the antigen and activate the complement system

Question 20

what is opsonization?

Answer 20

enhancing the phagocytic ability of phagocytes

Question 21

how does coating a pathogen with complement or antibodies enhance phagocytosis?

Answer 21

• by receptor mediated endocytosis
• phagocytes have receptors for complement protein and have receptors for antibodies. they recognize part of the antibody and then they phagocytosis whatever that antibody is binding to

Question 22

what are the three ways that antibodies do their job?

Answer 22

• binding antigens
• activate complement system
• neutralization

Question 23

• what is neutralization?

Answer 23

• binding and neutralizing bacterial toxins. Inhibiting bacterial access to host cells. Inhibiting viral entry into host cells
• enhancing phagocytosis of pathogens (opsonization)

Question 24

what letter does an antibody look like?

Answer 24

Y

Question 25

how many chains on an antibody?

Answer 25

four. two heavy chains (more medial) and two light chains

Question 26

on an antibody, where does an antigen bind to?

Answer 26

the ends of the 'Y' - essentially, the edges of the end of the heavy and light chains - called the FAB - fragment antigen binding

Question 27

the part of the antibody that is NOT the FAB, is called?

Answer 27

the FC portion - doesnt bind the antigen - fragment crystalline?? crystalline fs but idk what the F stands for

Question 28

what is the function of the FC portion of an antibody?

Answer 28

opsonization - enhances phagocytosis - also allows antibodies to activate complement

Question 29

what does the functionality of the antibody depend on?

Answer 29

the FC region - determines AFTER antigen is binded

Question 30

the specificity of the antibody depends on?

Answer 30

the FAB region - does this first

Question 31

what does a T cell receptor look like?

Answer 31

two chains that cross right before the antigen-binding site

Question 32

can a T cell recognize an antigen on its own?

Answer 32

no, we rely on other immune cells (dendritic cells) to take the antigen, chop it up into small pieces and present it on the surface using their own proteins. this happens in the lymph nodes

Question 33

when are T cells activated for foreign attack?

Answer 33

when the attack is on the surface of a cell that carrier foreign antigens presented on self-antigens (professional APC)

Question 34

what is the job of the MHC protein?

Answer 34

to be combined with a foreign peptide and present it on the surface of a cell

Question 35

the T-cell receptor does not only recognize the peptide but also recognizes the?

Answer 35

protein presenting on it

Question 36

what is the Major Histocompatibility Complex?

Answer 36

peptide fragments (antigen) bound to self proteins that are displayed on the surface of the APCs

Question 37

what are the two types of T cells?

Answer 37

1. Helper T Cells (Th) 2. Killer T Cells

Question 38

what is a protein on the surface of the helper T cells that allows us to recognize them? (the killer T-cell will not have this)

Answer 38

the CD4

Question 39

initial activation of a T cell starts at the dendritic cell and then goes where? and then? and then?

Answer 39

dendritic cell --> MHC protein --> foreign peptide --> TCR --> T-cell

Question 40

what cell is really good at killing parasites?

Answer 40

eosinophils - must be coated by special antibodies to activate eosinophils

Question 41

what do helper T cells (Th) do?

Answer 41

modulate activities of other immune cells and secrete chemicals that amplify the activity of other immune cells

Question 42

what are the names of killer T cells?

Answer 42

- CD8 (the marker that helps us recognize it is a killer T) - cytotoxic (CTL) - Tc - killer T cells

Question 43

what does the killer T-cell do?

Answer 43

- destroy host cells harboring anything foreign (viral infected cell; cancer cell) - bind to the viral antigen and self-antigen on the surface of the infected cell - may kill cell directly or through enzymes that cause the cell to self-destruct (apoptosis)