Lecture 41 Introduction to Immunology Flashcards
1
Q
Two forms of immunity
A
Innate immunity and Adaptive immunity
2
Q
Innate mechanisms
A
first line of defense, non-specific response
3
Q
adaptive mechanisms
A
second line of defense, highly specific with memory
4
Q
active immunity
A
antigens enter body and trigger both innate and adaptive immune system = long term protection
5
Q
passive immunity
A
antibodies given to person for period = short term protection (no memory cells)
6
Q
examples of passive immunity
A
antibodies passing from mother to foetus across placenta, breast milk
7
Q
cells in immune system derived from
A
common pluripotent hematopoietic stem cells in bone marrow
8
Q
two lineage from stem cells
A
myeloid and lymphoid
9
Q
myeloid lineage generates
A
- polymorphonuclear leukocytes
- monocytes
- dendritic cells
- mast cells
10
Q
lymphoid lineage
A
- B cells
- T cells
- NK cells
11
Q
polymorphonuclear leukocytes
A
- neutrophil
- eosinophil
- basophil
12
Q
polymorphonuclear leukocytes are also called
A
granulocytes = same thing
13
Q
granulocytes are characterised by
A
multilobed nuclei, cytoplasmic granules
14
Q
neutrophils
A
- principal phagocytic cell of innate immunity
- migrate to site of infection
- release oxygen free radicals
- release degranulate proteins
- release cytokines (TNF)
15
Q
microbicidal
A
agent in killing microscopic organisms
16
Q
eosinophils
A
- defender against multicellular parasites
- allergy and asthma
- ‘e’www for parasite = ‘e’osinophils
17
Q
basophils
A
- inflammatory allergic reactions
- release potent vasodilator = histamine`
18
Q
monocytes
A
- bean shaped nuclei
- mature into macrophages
- kill pathogens by phagocytosis
- free radical production
- inflammatory cytokines
19
Q
myeloblast matures into
A
basophil, neutrophil, eosinophil, monocyte
20
Q
monocyte matures into
A
macrophage
21
Q
common myeloid progenitor generates
A
megakaryocyte, erthyrocyte, mast cell myeloblast
22
Q
megakaryocyte matures into
A
platelets
23
Q
common lymphoid progenitor
A
Natural killer cell, small lymphocyte
24
Q
small lymphocyte generates
A
T lymphocyte and B lymphocyte
25
B lymphocyte turns into
plasma cells ( and memory cells)
26
macrophages
- innate and adaptive immunity
- phagocytose
- microbicidal mechanisms
- APC
- recruit neutrophils
27
dendritic cells
- phagocytose
- procecss and present antigens = APC
- stimulate T cells to initiate immune response
28
mast cell
- close association with allergy and inflammation
- release histamine
- phagocytose
29
Neutrophils have receptor that detects formylated peptides, why?
bacteria incorporate N-formyl methionine into first position of peptides = recognised by receptor
30
innate immune system = what receptors on cells detect foreign material
Toll-like receptors = TLR
31
what molecules are recognised as foreign by TLRs
lipopolysaccarides on bacteria, proteins in flagella, double stranded RNA
32
how do lysozymes work against bactera
break bond between N-acetylglucosamine and muramic acid
33
how does penicillin work
interferes with synthesis of peptidoglycan in cells walls
34
mechanism of resistance to penicillin
- mutation in penicillin binding proteins
- production of B-lactamase to detsory B-lactam ring
- resistance transferred by 'transformation' and plasmids during 'conjuagtion'
35
B lymphocyte
produces antibodies, presents antigens, produces memory cells
36
T lymphocytes
- stimulates B cells
| - kill virally infected and tumour cells
37
what is NK cell derived from as part of lymphoid lineage
large granular lymphocyte
38
NK cell
- release perforins
- release granzymes
- trigger apoptosis
- tumour immunosurveillance
39
primary lymphoid tissue = development and maturation of lymphocytes
bone marrow = B cells
| thymus gland = T cells
40
secondary lymphoid tissue
lymph nodes, spleen
41
lymph nodes found where
jaw, neck, axilla (armpit), elbow, groin, behind knee
42
spleen located
lymphoid organ in abdomen
43
function of spleen
removes damaged/old RBCs, activates lymphocytes
44
structure of spleen
red pulp = erythrocytes removed
| white pulp = lymphocytes stimulated
45
innate immune system components
1. mechanical barriers
2. physiological
3. chemical mediators
46
mechanical barriers
skin, mucous membranes, cilia propel microbes out of body
47
physiological immune system barrier
stomach acid, fever response hear inhibits pathogen growth
48
chemical mediators innate system
lysozyme cleaves bacterial cell wall, interferon induces antiviral defenses in cells
49
phagocytic leukocytes
monocytes, macrophages, dendritic cells, neutrophils
50
two types of adaptive immune response
humoral and cell-mediated immunity
51
humoral immunity
B cells = produce antibodies
52
cell-mediated immunity
T cells
53
non infected tissue, cell behaviours
In blood = monocytes and neutrophils pass healthy tissue
| In cells = macrophage digests dead cells, dendritic cells are dormant
54
wave 1 infected tissue = dendritic cells
exit infected cell, migrate to lymph nodes, signal to lymphocytes
55
wave 1 infected tissue = neutrophil action
from blood-stream enter infected cells
56
wave 2 infected tissue = monocytes
flood in from blood-stream = become inflammatory macrophages
57
wave 2 infected tissue = neutrophils
killed pathogen and themselves in the process = pusu
58
wave 2 infected tissue = macrophage
clear debris, some migrate to lymph nodes
59
infected tissue = resolution
inflammatory macrophages change properties to repair damage
60
what cells do macrophages phagocytose?
DYING cells = recognised as plasma membrane changes profile when a cell dies
OPSIONIZED cells =
surface coated with complement proteins or antibodies
61
opsionised cells and pathogens
immune response concept = cells/pathogens coated in opsonins to be recognised by macrophages
62
opsonin
any molecule that enhances phagocytosis by marking an antigen for an immune response
63
opsonin examples
antibodies = IgG and IgM
| complement proteins = C3b and C4b
64
Fc receptor on macrophage
binds to antibodies coating cell/pathogen
65
ANA
antinuclear antibodies
66
CD4+ cell
T helper cell
67
CD8+ cell
Cytotoxic T cell
68
dendritic cell specialisation
specialised receptors on surface
69
professional APCs
macrophages, dendritic cells, B cells
70
what makes professional APCs
all have MHC II comlexes
71
immunogen
an antigen that causes an immune response
72
antibodies are called
immunoglobulins
73
different classes of anitbodies
IgA, IgD, IgE, IgG and IgM
74
how many total B cells in blood
around 3 million
75
how many B cells in blood specific to one specific antigen
about 30
76
when specific antibodies are produced in B cell
transported to surface on B cell = B cell receptors (BCRs)
77
when do B cells divide
when B cell binds to its cognate antigen = proloferation
78
after a week of division, now many identical B cells in blood
around 20,000
79
vdj recombination
B cells and T cells = randomly assemble different gene segments to generate unique antigens
80
vdj segments = building blocks for variable region of antibody
```
V = variable
D = diversity
J = joining
```
81
Fc region on anitbody
the constant region, encoded by C - gene
82
how many different variations of segments in coding for antigen binding site
46 variable, 23 diversity, 6 joining
83
how many c-gene variants exist
5
84
what are the c-gene segments
```
Alpha (IgA)
Delta (IgD)
Epsilon (IgE)
Gamma (IgG)
Mu (IgM)
```
=hence the classes of antibodies are characterised by the constant region, Fc
85
antibody diversity is because
rearrangement of immunoglobulin gene segments to create huge diversity in mature B cells
86
somatic hypermutation
.
87
function of antibodies = opsonization
bind to bacteria and viruses, Fab region of antibody binds to antigen and Fc tail region binds to Fc receptor on macrophage = phagocytosis
88
function of antibodies = pathway
classical pathway activated = lysis of bacteria, triggers complement activation
89
primary response of antibody
following exposure: slow rise in IgM, the slow rise in IgG
90
secondary response of antibody
following exposure: rapid, great rise in IgG, limited rise in IgM
91
T cells respond to
antigens presented via the MHC of another cell = antigens bound to cells, not found in blood
92
MHC
Major Histocompatability Complex
93
histocompatible meaning
two individuals are histocompatible if tissues can be transplanted between without rejection
94
MHC variance
not because of VDJ recombination or TCR, we inherit polymorphic genes from parents
95
antigens as complex with MHC molecules
APCs = peptides presented in association with MHC
96
importance of MHC association with antigens
allows immune cells to distinguish between normal antigens on surface of all cells, and foreign ones
97
endogenous vs exogenous meaning
```
endogenous = within or inside cell
exogenous = outside
```
98
MHC class I present where
almost every cell in body
99
MHC class II present where
only on specialised APC immune cells = macrophages, dendritic cells, B cells
100
MHC class I present what antigens
endogenous antigens, synthesised in cytoplasm
101
MHC class II present what antigens
exogenous antigens, originate extracellularly from foreign bodies
102
production of MHC class I molecules
1. samples of proteins made on ribosomes are chopped up into short peptides by the proteasome
2. fragments transported to ER, where peptides of ~10 amino acids can bind to MHC class I proteins
3. complex transported via golgi to cell surface
103
production of MHC class II molecules
1. phagocytosis
2. foreign peptide fragments are bound to MHC class II proteins in endosome]
3. transported to cell surface
104
what cell recognises MHC class I
CD8+ = cytotoxic T cells
105
what cell recognises MHC class II
CD4+ = T helper cell
106
best way to kill virus
destroy cells that virus has infected before the cell releases new viral particles
107
best way to kill virus/yeasts
generate antibodies = agglutination of particles, mark them for ingestion or further attack by complement system
108
autoimmunity
misdirected adaptive immune response = type 1 diabetes, rheumatoid arthritis, Crohn's disease, thyroiditis, multiple sclerosis
109
hypersensitivity reactions
over reaction of adaptive immune response = peanut allergy, asthma
110
immunodeficiencies
components of immune system are absent/defective = AIDS
