SECRETS Immuno - Basics

Question 1

primary lymphoid organs

Answer 1

bone marrow = B & T
thymus = T
fetal liver

where lymphocytes mature

Question 2

secondary lymphoid organs

Answer 2

appendix
tonsils
peyer’s patches

mature lymphocytes respond to antigens on APCs

Question 3

innate immunity

Answer 3

first line of defense

nonspecific

PRRs –> recognize PAMPs

prevent microbes from entering
destroy/limit growth

neutrophils, macrophages, eosinophils, basophils, mast cells, NK cells

Question 4

adaptive immunity

Answer 4

B, plasma cells
helper T, cytotoxic T cells
specific, memory

Question 5

bridge from innate – adaptive

Answer 5

dendritic cells

Question 6

cell mediate immunity

Answer 6

helper t Cells
vs virus, fungi, mycobacteria

type IV hypersensitivity, tumor destruction, graft rejection

Question 7

MHC class I

Answer 7

all nucleated cells
interact with CD8+ T cells –> destruction

display nonself peptides that have been processed intracellularly

Question 8

MHC class II

Answer 8

APCs = dendritic cells, macrophages, memory b cells
interact with CD4+ T cells –> upregulate Th cytokine production –> macrophage activation, plasma cell proliferation

display exogenous nonself peptides obtained via phatocytosis, endocytosis

Question 9

ADCC

Answer 9

bing IgG to Fcy receptors

destruction via phagocytes or NK cells

Question 10

IgA

Answer 10

mucosal immunity

poor activator of complement

Question 11

IgD

Answer 11

on mature B cells

unclear role

Question 12

IgE

Answer 12

on tissue mast cells and blood basophils
mediate type I hypersensitivity
parasitic killing via ADCC

Question 13

IgG

Answer 13

in blood, crosses placenta
longest half life
ligand for Fc receptors
activate classical complement pathway
most abundant Ig in secondary immune response
highest affinity (strength)

Question 14

IgM

Answer 14

in blood, pentamers
activate classical complement pathway
earliest Ab produced
most abundant Ig in primary immune response
highest avidity (number of binding sites)

Question 15

neutrophil chemotaxis

Answer 15

IL-8
C5a
LTB4

Question 16

C1 esterase inhibitor deficiency

Answer 16

overproduce anaphylatoxins –> recurrent angioedema

contraindication for ACEi

Question 17

C2 or C4 deficiency

Answer 17

resemble autoimmune disease, usually asx

C2 is most common deficiency, assoc with septicemia (strep pneumo)

Question 18

C3 deficiency

Answer 18

reduced opsonization –> recurrent pyogenic infections

type III hypersensitivity = decreased immune complex clearance

Question 19

C5-8 deficiency

Answer 19

no MAC
increased risk of neisseria infections

MAC can kill most unenapsulated gram neg organisms

Question 20

DAF deficiency

Answer 20

increased complement mediated hemolysis

paroxysmal nocturnal hemoglobulinuria

Question 21

macrophage

Answer 21

CD14+CD16+
CD40+

phagocytosis

APC to T cells

secrete IL-1, IL-6, IL-8, IL-12, TNF-a

Question 22

eosinophil

Answer 22

phagocytic
parasitic organisms
extremely basic proteins in granules

Question 23

basophil

Answer 23

nonphagocytic
allergic response
release histamine, IgE on surface

Question 24

mast cell

Answer 24

allergic response, similar to basophil

release histamine, FcE on surface

Question 25

helper T cell

Answer 25

CD4+ activated by foreign antigen on MHC II regulate fxn of other immune cells

Question 26

TH1

Answer 26

induced by IL-12 secrete IFN-y --> activate macrophages & TH1, suppress TH2, kill intracellular pathogens IL-2 --> activate CTLs & propagate response, T cell proliferation

Question 27

TH2

Answer 27

induced by IL-4 ``` secrete IL-4 --> promote IgE & IgG class switch & B cells to plasma cells IL-5 --> promote eosinophil prolif, aid IgA class switch IL-10 --> anti-inflammatory ```

Question 28

cytotoxic T cell

Answer 28

CD8+ direct cell killing MHC I perforins, granzymes, IFN-y, TNF-B, FasL

Question 29

B cell

Answer 29

CD19+CD20+ diff into plasma cells release antibodies APC for Th cells (MHC II)

Question 30

NK cells

Answer 30

CD16+ large granular lymphocyte lyse virally infected cells (ADCC) and tumor cells with less MHC I perforins, granzymes, IFN-y, TNF-a

Question 31

secreted by T cells

Answer 31

IL-3 | hematopoietic stem cell diff into myeloid progenitors

Question 32

macrophage cytokines

Answer 32

``` TNF-a = acute phase, responsible for septic shock and cachexia IL-1 = acute phase, fever IL-6 = acute phase, fever IL-8 = neutrophil chemotaxis IL-12 = TH1 cell diff, NK activation ```