abbas chapter 1

Question 1

innate immunity

Answer 1

always present
blocks entry of microbes
includes:
- epithelial barriers
- phagocytes (esp. NK cells)
- complement

takes 6-12 hours
doesn’t react against noninfectious foriegn sugstances

Question 2

adaptive immunity

Answer 2

B-lymphocytes create antibodies
T-lymphocytes become effector T cells
acts 1-5 days post infection
recognizes antigens but only recognized if the antigens are delivered to lymphatics

Question 3

types of adaptive immunity

Answer 3

humoral and cell-mediated

Question 4

humoral immunity

Answer 4

for extracellular microbes
antibodies produced by B lymphocytes
B lymphocytes recognize extracellular antigens

Question 5

cell-mediated immunity

Answer 5

for intracellular microbes
t-lymphocytes activate phagocytes and kill host cells
t lymphocytes recognize antigens produced by intracellular microbes

Question 6

humoral immune response (microbe type, responding lymphocytes, effector mechanism, functions)

Answer 6

• extracellular microbe
• B lymphocytes respond
• secrete antibody
• block infections and eliminate extracellular microbes

Question 7

cell-mediated response (microbe type, responding lymphocytes, functions)

Answer 7

if phagocytised microbe:

• microbe in macrophages
• helper T lymphocytes respond
• activate macrophages to kill phagocytosed microbes

if intracellular microbes:

• intracellular microbes replicate within the infected cells
• cytolytic T lymphocytes respond
• kills infected cells and eliminates reservoirs of infection

Question 8

clonal selection hypothesis

Answer 8

mature lymphocytes with receptors for many antigens develop before the encounter with those antiges - when antigen presents, that clone cell proliferates

Question 9

primary immune response

Answer 9

response to first exposure to antigen

mediated by naive lymphocytes

Question 10

secondary immune response

Answer 10

due to subsequent encounters with same antigen that created a primary immune response
faster and larger response due to activation of memory lymphocytes

Question 11

phases of response (list)

Answer 11

recognition
activation of lymphocytes
- clonal expansion
effector phase

Question 12

recognition phase

Answer 12

first phase of immune response

naive antigen-specific lymphocytes locate and recognize the antigens of microbes

Question 13

activation phase

Answer 13

second phase of immune response
requires binding of antigen to antigen receptors of lymphocytes (signal 1) and other signals from microbes and innate immune system (signal 2)
includes clonal expansion step
some lymphocytes also differentiate into effector cells - secrete antibody (b) or kill infected cells (t)

Question 14

clonal expansion

Answer 14

occurs during activation phase of immune response

rapid cell division of lymphocytes that encounter antigens

Question 15

effector cells

Answer 15

generated during clonal expansion step of immune response
some B cells secrete antibody and some T cells kill infected cells
include lymphocytes and other leukocytes - B and T leukocyte lineages, and also granulocytes and macrophages

Question 16

effector phase

Answer 16

third phase of immune response
effector cells and their products eliminate
only become effector cells when naive lymphocytes get both 1st and 2nd signals

Question 17

what happens to cells from the immune response after the infection is eliminated?

Answer 17

most cells that were activated die via apoptosis

memory lymphocytes remain and migrate through lymph - some go to site of infection

Question 18

lymphocytes

Answer 18

the only cells with specific receptors for antigen
key mediators of adaptive immunity
B - mediate humoral response - produce antibodies
T - mediate cell-mediated immunity - only recognize antigens bound to mHC on APCs
NK cells - innate immunity
CD4+ cells and CD8+ cells

Question 19

CD4+ cells

Answer 19

mature in bone marrow
helper T cells because help B to produce antibodies and help phagocytes to destroy ingested microbes
reduce cytokines
when become effector cells, produce cytokines that activate B cells and macrophages

Question 20

CD8+ cells

Answer 20

cytolytic or cytotoxic = CTLs
kill cells harboring intracellular microbes
mature in thymus

Question 21

B cells

Answer 21

mediate humoral immunity
produce antibodies
b-cells become effector cells - become plasma cells - secrete antibody

Question 22

antigen presenting cells

Answer 22

in epi
capture antiges and transport them to peripheral lymphatic tissue
includes dendritic cells, macrophages

Question 23

dendritic cells

Answer 23

professional APCs
capture protein antigens of microbes tht enter through epithelia and transport antigens to lymph nodes where portions of antigen recognized by T lymph

Question 24

macrophages

Answer 24

in epithelium, phagocytose microbes that invade

display these protein antigens to T cells

Question 25

professional APCs

Answer 25

also present secondary signals to help activate T cell proliferation and differentiation

Question 26

generative tissues of immune system

Answer 26

primary

T and B lymphocytes mature and become competent to respond here

Question 27

peripheral tissues of immune system

Answer 27

secondary
where adaptive immune responses to microbes instigated
lymph nodes, spleen, mucosal and cutaneous immune systems
concentrate antigens, APCs and lymphocytes
T and B separated into different anatomical compartments - kept there by cytokines expressed in those areas

Question 28

lymph nodes

Answer 28

peripheral/secondary tissue
substances absorbed from epithelia and tissues
APCs in nodes sample antigens in lymph as it passes through nodes and dendritic cells go here
antigens become concentrated in draining lymph nodes
B cells are in follicles in the cortex (FDCS there too), while T outside follicles (as are dendritic cells)
follicles have germinal center when activated

Question 29

spleen

Answer 29

blood equivalent to the lymph node
dendritic cells and macrophages trap and concentrate blood borne antigens - lots of phagocytes
B in follicles too

Question 30

cutaneous and mucosal immune tissues

Answer 30

cutaneous under epithelium

mucosal in GI and respiratory tracts (peyers patches and pharyngeal tonsils)

Question 31

T lymph maturation

Answer 31

matures in thymus
migrate to lymph nodes through HEVs
activated by macrophages or other APCs presenting antigens
they then differentiate and proliferate and migrate into tissues colonized by infectious microbes

Question 32

high endothelial venules (HEVs)

Answer 32

mature t lymphocytes migrate into lymph nodes through them
express carbohydrate ligands that bind to L-selectin receptor on naive T cells so that the naive T cells bind losely to HEVs
cytokines expressed in paracortical regions induce t cells to bind more finally to HEVs and migrate through