Unit 4- Specific Resistance (Adaptive Immunity) Flashcards Preview

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Flashcards in Unit 4- Specific Resistance (Adaptive Immunity) Deck (63):
1

where do B-cells mature?

in the bone marrow

2

where do T-cells mature?

thymus

3

what are APCs?

antigen presenting cells

4

what cells are professional APCs?

neutrophils, macrophages, T-cells and B-cells

5

how do APCs display antigens?

using the protein complex MHC-II, they display Ags of phagocytized pathogens on their surface

6

how do B-cells contact an antigen

either directly, or on the surface of an APC, then they make antibodies in response

7

what do helper T-cells do?

they activate B_cells and T-cells (act as managers/match-makers)

8

2 types of B-cells?

memory B cells, plasma B cells (the effector cells, making antibodies)

9

2 types of T cells?

memory T cells and cytotoxic T cells (Tc)- teh effector T cells attacking pathogen directly

10

effector cell of B cells are called...

plasma B-cells

11

effector cell of T cells are called.

cytotoxic T cells (Tc)

12

what do Abs do?

ANOC out punch!!
1) Agglutination
2) Neutralization
3) Opsonization
4) Complement Activation

13

aggultination?

some Abs stick together, clumping the target

14

neutralization

Abs bind the surface of a pathogen, toxin and prevent its function (prevents pathogen from moving fwd by piling on top)

15

opsonization

Ab-bound cells are more often phagocytized

16

complement activation

complement factors poke holes (MACs) to lyse membrane

17

MHC stands for...?

multihistocompatibility complex; it takes proteins from digested bacteria and presents on surface of a neutrophil

18

2 classes of MHC

MHC Class 1- foudn on all human nucleated cells
MHC class II- found on some types of WBCs (the antigen presenting cells)

19

what are MHC genes known as?

HLA genes

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antigen

substances, specific molecules usually proteins, that bind to lymphocyte receptors (B/Tcell)

21

epitope

the segment of the antigen that is recognized by lymphocyte receptors (shape is recognizable)

22

immunogens

agents that can provoke an immune response and react with the prodcts of that response

23

what antigens are not immunogens?

1) haptens (when they're too small)
2) when they're too similar to normal cellular proteins
3) when they either don't have a static structure, or have a highly repeating structure

24

haptens

are too small, and cannot elicit an immunological response, although bound to T/B cells. HOwever, they can bind to larger molecules (carriers)

25

example of an antigen that isn't immunogenic because of similarity to normal cell proteins?

streptococcus pyogenes- molecular mimickry

26

what antigens have a changing structure?

lipids and globular proteins with slimay, dynamic structures... they're poorly immunogenic

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what antigens have a repeating structure?

starch, glycogen and other polysaccharides. they're poorly immunogenic

28

what 6 factors determine immunogenicity of an Ag?

chemical composition, size, complexity, genetic disparity, and processing by APCs

29

proteins, carbohydrates, pure lipids--- rate on immunogenicity

proteins are highly immunogenic, carbs are weakly and pure lipids are non-immunogenic

30

pattern of size and immunogenicity of Ag?

larger the size, greater the immunogenicity

31

structural complexity and immunogenicity of Ag?

greater the complexity, greater the immunogenicity

32

what structure of Ag molecules are almost most immunogenic?

aromatic molecules (as compared to alipathic molecules)

33

autograft

transplant from self

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isograft

transplant from twin

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allograft

transplant from unrelated person

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xenograft

trasnplant from animal (different species)

37

autoantigens

when your own proteins becoem immunogenic and recognized as an antigen--> autoantibodies are produced

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alloantigens

antigens derived from other people (ie. blood transfusion or organ trasnplant)

39

what are 2 ways of minimizing risk of genetic disparity?

1) umbilical cord blood biobanking-- cord blood rich in hematopoietic stem cells)
2) autologous blood transfusion- bank your own blood prior to surgery so you could receive your own blood for transfusion

40

adjuvants

factors external to the substance that can make an Ag more immunogenic. Adjuvants are agents added to vaccines to enhance the vaccines' immunogenicty

41

example of an adjuvant

alum and dead bacteria, as well as oil-in-water emulsion (clumps molecules together) while alum stimulates chemotaxis

42

components of a vaccine:

1) Ag (primary
2) Adjuvant
3) Preservative

43

epitope

immunogenic or antigenic determinants, they are part of immunogen/antigen that interact with the ag-binding site of the antibody/T-cell receptor, around 4-6 a.a. long

44

what's the most important part of an epitope?

its 3D shape

45

immunoglobulins

receptors on the surface of B-cells and T-cells

46

lymphocyte immunoglobins mutate during when?

hematopoiesis

47

what is the result of immunoglobulin mutation?

immunoglobulin Ag binding site changes shape.. final shape is random depending on mutation

48

VDJ Recombination

genetic recombination that consists of 3 genes: Variable, Diverse, Joining.

49

how many possible epitopes are there as a result of VDJ Recombination?

3 x 10^11 epitopes

50

example of naturally acquired active immunity

exposure to pathogen

51

example of articficially acquired active immunity

exposure to vaccine

52

example of naturally acquired passive immunity

breast feeding/Abs from mother's placenta

53

example of artificially acquired passive immunity

premade Abs from immune donor or purified IgGs

54

what Abs do mother's pass to babies through breast feeding?

IgA, but it eventually runs out and baby needs to develop own immune system

55

prophylaxis

administer an agent to prevent disease before exposure has occured

56

source of antigens? 4

killed whole cell or inactivated virus, lived, attenuated cells/virus, proteins or other antigenic molecules purified from pathogen, genetically engineered antigen

57

pros and cons of killed/inactivated pathogens?

pros: almost always dead/safe. cons: does not multiply, higher dose and booster shots needed

58

pros and cons of attenuted pathogen

pros: multiples somewhat, long lasting protection. cons: small risk of reversion to active pathogen

59

examples of attenuated pathogenvaccines

BCG (Tb), OPV (oral polio vaccine), toxoid (Td)

60

pros and cons of purified molecules

pros: no living pathogen, cons: ag may change shape during purification

61

examples of purified molecules

anthrax, hep B

62

pros and cons of recombinant proteins

pros: cheap, safe; cons: clonal, pathogen can evolve resistance easily (it only represents one protein)

63

herd immunity

when over 95% of people in the population are immune to the infectious agent