Immune system Flashcards
(140 cards)
1
Q
what type of disease is HIV?
A
immunodeficency virus
2
Q
what are the primary organs of the immune system?
A
- stem cells from the yolk sac and fetal liver
- bone marrow
- thymus gland
3
Q
what are secondary organs?
A
these are the organs which during adulthood take care of our immune system
4
Q
what are the secondary organs?
A
lymph nodes
spleen
Mucosa-associated lymphoid tissue
5
Q
what proportion of the population did small pox kill?
A
1 out of 10 people
6
Q
why were the milkman’s not affected by small pox?
A
because working with cows they came into contact with cow pox which gave them immunity against small pox
7
Q
what were the last cases of small poxs?
A
- last person to contract it was in 1977 in Somalia, he survived with treatment
- 2 accidental laboratory cases; 1 death in 1978
8
Q
what is an antigen?
A
it is a toxigen or a foreign substance that induces an immune response in the body?
9
Q
what are the different types of antigens we have encountered?
A
-immunogen: initiates immune response
-hapten: it is a small bacteria which requires a carrier to become an immunogen
-allergen will provoke allergic responses
-tolerogen is a substance that invokes a specific non-reponsiveness
Ligand: produced when antigen binds to antibody
10
Q
what are the 3 lines of host defense?
A
the coverings of the body
the innate immune response
the adaptive immune response
11
Q
if someone steps on glass what would be the first line of defence to be affected?
A
the skin and mucous membrane which provide unpleasent living conditions for the microorganisms
12
Q
what are some of the factors that affect the living conditions for microorganisms in the skin and mucous membrane
A
- epidermis
- mucus
- pH
- enzymes
13
Q
what are the first cells involved in immune response?
A
macrophages
14
Q
what are PAMPs?
A
they are pathogen associated molecular patterns
not present oh human cells
15
Q
what are some examples of PAMPs that can be found on bacterial cells
A
LPS of gram-negative bacteria
peptidoglycan wall of gram positive bacteria
16
Q
what part of the immune system recognizes PAMP?
A
Pattern recognition receptors
17
Q
what is a toll-like receptor (TLR)?
A
highly conserved trans membrane 1 receptor
essential for microbial recognition via PAMPs
they belong to PRRs
18
Q
what is the importance of mammalian TLR?
A
In humans, recent studies suggest that certain naturally occurring variants in a specific TLR are associated with increased risk of certain diseases.
19
Q
what is the innate immune system?
A
it is a natural and non specific which lacks memory
20
Q
what are some of the cellular factors found in the innate immune system?
A
- phagocytic cells
- cells with inflammatory mediators
21
Q
give examples of phagocytic cells
A
- neutrophiles
- macrophages
- interdigesting dendritic cells
22
Q
what are some of the humeral factors found in the innate immune system?
A
- acute phase reactants
- cytokinins (interferon-alpha)
23
Q
give examples of some acute phase reactants
A
- c-reactive protein
- complement
- interleukin
24
Q
what are some polymorphonucleur granulocytes?
A
- neutrophils
- eosinophils
- basophils
25
describe the neutrophil
- major macrocytic cell
| - multiple nucleis
26
describe dendritic cells?
-surface dendrites will phagocytose some bacteria and hold some on its surface
27
where does antibody creation occur?
in lymphocytes
28
what does MDNCF stand for?
monocyte derived neutrophil chemotactic factor
29
in the case of an immunological disease what may be abnormal in the human body?
thymus
bone marrow
lymph nodes
30
what happens when an activating substance is released by bacteria and damaged tissue?
the neutrophil rolls along the capillary wall making its way to capillary endothelial cells
31
how is the microbe taken into the cell?
the neutrophil containing the microbe adheres to the membrane and its taken into the cell by endocytosis and taken off as a phagosome
32
what does the phagosome interact with?
it interacts with the cytoplasm lysosome
33
what happens to the neutrophil?
it will die (suicide) and result in the formation of the NET
34
how is Pus formed?
dead bacteria + NET
35
are natural killer cells activated on every cell in the body?
yes
36
how does the natural killer cell function (general description)
- extracellular micro in taken in through endocytosis
- phagosome formation
- lysosome joins to phagosome
- formation of phagolysosome
- end products get released into the cell
37
the MHC- class 1 on normal cells is recognized by what?
by killer cells immunoglobin like recptors
38
does natural killer kill normal cells?
no
39
do B cells interact with MHC?
no
40
can the MHC be restricted by the Natural killer cells?
no, beause interaction with MHC is not required for their activation
41
what happens when natural killer cells are activated?
they release ganyle contents which induce apoptosis
42
how many pathways can be taken to activate the complement?
3
- classical
- mb-lectin
- alternative
43
what does the alternative pathway consist of?
activated by interraction between CHO on the surface of the microbe and inactivated complement.
HENCE OCCURS ON PATHOGEN SURFACE
44
what does the classical pathway use to activate the complement
use of antigen consisting of antibody complexes
45
how does the MB-lectin pathway function activate the complement?
lectin bind to the pathogen surface activating the complement
46
what happens when the complement is activated?
- recruitement of inflammatory cells
- opsonization of pathogens
- killing of pathogens
47
what type of cell links the innate and adaptive immune system together?
dendritic cell
48
what are the 4 major components of inflammation
heat (calor)
pain ( dulor)
redness (rubor)
swelling (tumor)
49
what do dendritic cells make their way back to?
make their way back to the lymph nodes
50
what does the innate immune response result in?
inflammation
51
what is the cellular sequence of the innate immune system?
```
1- tissue macrophage
-recognition of PAMPs with TLR
-bacterial phagocytosis and digestion
-prodution of MDNCF
2- the neurtophil
-bacterial phagocytosis
bacterial destruction
-neutrophil suicide
-Pus
```
52
what are the characteristics of the adaptive immune system
specific
| acquire
53
what do both humeral and cell mediated immune responses have early on?
T helper cells
54
what type of cell is missing in AIDS patients?
T helper cells
55
what is the late process mediated by>
CD-8
56
what is the present in the humeral adaptive system on the later phase?
humeral antibody
57
what is the adaptive immune system specific to?
antigen and epitope
58
what are antigen presenting cells (APC)?
MHC+ peptide
59
what are some of the APC?
- Interdigesting dendritic cell
- macrophage
- B vlymphocytes
60
what differs between the class 1 and class 2 HLA structures
```
class 1: the chains are markedly different molecular masses, a large alpha chain and a small beta-2 microglobulin chain
class 2: alpha and beta chains are almost the same size
```
61
what is the MHC complex found in mice?
H2 complex
62
what is the MHC complex found in humans?
HLA complex
63
on what cells is the MHC2 complex found?
dendritic cells, macrophage and B cells
64
foot ball version of immunity... summarize
- on the offensive side we have bacteria and on the defence we have the 3 layer of defence.
- the bacteria makes its way and tries to attack and gets captured by the macrophage, which partially stops it, then the neutrophil captures part of it (and dies), then the dendritic cell joins to it and captures it
65
what is the human equivalent to the bursa of fabricus in the bird?
bone marrow
66
what is the lymphatic rout in humans?
in utero:
it begins in the yolk sac
goes to the liver and then the bone marrow and to the thymus
67
is the sulfide bond critical to the antibody structure
no
68
where in the antibody is the binding site located?
between the light and heavy chain
69
what are some important characteristics of pre T cells?
they are double positive cells
| CD4 [helper] AND CD8[ killer]
70
what happens to Pre T cells
-the respective B and T cells spend time in bone marrow and thymus where they divide and differentiate to be made SPECIFIC
71
what is a particularity of the B and T cells made in utero by pre T cells?
they all have their own specificity
72
where are B cells located once inside the lymph nodes?
along the periphery of the nodes
73
where are T cells located once inside the lymph nodes?
along the deep cortex of the medulla
74
what is the lymphatic route?
begins in utero in the yolk sac.
stem cell makes its way into the bone marrow and thymus
then make their way to the lymph nodes and spleen where T and B cells live in different areas (thymus= T and bone marrow= B)
75
for what peptide is the T cell specific for?
MHC-2
76
what is co-reception and what it it essential for?
co-recteption involved the binding of B7 dendritic cell to a CD28 receptor on the T cell
without this, immune response cannot function
77
can the macrophage act as an antigen presenting cell?
yes
78
what happens when Macrophage acts as APC?
it will call the neutrophile in, which will take up a part of the cell and die, resulting in the Net, then the dendritic will pick up the bug and make its way to the regional lymph nodes.
79
how is the immune response stopped once not required?
throught the process of checkpoint inhibition, CTA4 and PD1 sometimes Regulatory T cells will be able to stop the immune response
80
what is the role of CTLA4?
it stop the activation of the T cell by binding to B7
81
explain the process taken by dendritic cell in presence of a bug
- dendritic cell picks up a peptide and bring it next to CD4
- TH2 cell joins to the peptide of MHC2 of the dendritic cell
- CTLA4 and TTFB are expressed and turn off immune in adults
- reception and coreception is established between dendritic and T cell
- binding of CD40L to CD40 of B cell and produce antibodies causing for 3 IL (4,5,6) to go from T cell to B cell allowing for multiplication
82
is it easy to visualize the structure of albumin? why?
yes
| due to its high concentratio
83
nare globulin structure easy to visualize?
no, it is too heterogenous
84
what has allowed to identify and analyze the structure of a single Y globulin structure?
Multiple Myeloma
85
what is the basic structure of antibodies?
four chains
| with 2 identical light chains (kappa or lamba) which determines the immunoglobulin type
86
what determines the classes of immunoglobulin molecule
the heavy chains
87
what do lab fragments result in?
Fab which is an antigen-binding fragments
| Fc which is a crystallizable fragment which determines the biological activity of an Ig class
88
identify its respective immunoglobin type?
First Ig made in ANY immunological response
involved in complement binding
IgM
89
identify its respective immunoglobin type?
| involved in placental transfers and complement binding
IgG
90
identify its respective immunoglobin type?
| Has secretory properties (MALT and mucosa)
IgA
91
identify its respective immunoglobin type?
| binds to mast cells and has mastocytophilic properties
IgE
92
how many subclasses does IgG have?
4
93
how many subclasses does IgA have?
2
94
how could you describe IgM?
it is pentavalent (5 monomers) and has 10 binding sites (decavalent)
95
how could IgA be described?
dimeric (2 monomers) and 4 binding sites (tetravalent)
96
what happens when the antibodies have nothing to kill?
antibodies can neutralize toxins
97
how does the neutralization of toxins occur in the complement system?
C1q binds followed by C1r- C1s then C4, C2 and C3
98
what acts as neutrophil attracting molecules in the complement system?
C3-C5 of the complement system
99
what methods can be used to kill “bugs” using the complement system?
C5-C5 brings in neutrophiles
| C7-C9 formes pores in the membrane causing for the bug to die
100
what is C3 of the complement system?
it is an neutrophile chemotactic hence it allows neutrophile phagocytosis, death and NET
101
in what does C3 break down into?
C3a and C3b
102
the binding of C7-C8-C9 is also known as what?
mac complex
103
what does each molecule of the complement system do?
it will amplify the waterfall
104
what do the products of C3 and C5 do?
they enhance neutrophil phagocytosis
| hence they act as chemokines
105
which molecule of the complement sequence punches a hole in the bacteria
C9
106
what can the alternative pathway be activated by?
- LPS (a PAMP)
| - complement
107
what is the role of LPS in the alternative pathway
turn on the innate immune response
108
what role does the complement play in the alternative pathway
enhances phagocytosis C3 and C5
109
how is antibody formed according to Linus?
it is instructible
non specific proteins will come and wrap around the antigen
it floats off
110
what is Paul Ehrlich’s theory for antibody production?
cells live through side chains on the surface of cells. if toxins come, they block the side chains causing cell to die. to counter this effect, cell will produce more of itself
111
what are some characteristics of pro-B cells?
first made in utero
lack receptors
can only go forward
112
what cell is the final maturation stage of the b cell?
plasma cell
113
how is the genes of the cell selected and put together?
randomly
114
what is the first constant region to be selected?
u is always the first as it is the one involved with IgM
115
what ribosomal structure is taken up by the cytoplasm to make IgM antibodies?
mRNA
116
if you want a class switch that will convert IgM into IgG what must be done?
u needs to be switched for Y3 which will yield IgG
117
what turns off immune response?
PD1
| CTLA4
118
what happens once the system is turned off in regards to the molecules which turn it off?
they are now acquired and the adaptive system will remember it.
119
where are memory cells generally stored?
in the apical light zones of the lymph node
120
why are vaccines often given in 2 doses?
the first does increases antibody production, where as for the second dose we have memory and so class switch enables to rapidly synthesize IgG antibodies
121
which cell is more diverse? B cell or T cell?
T cells
| helper and cytotoxic
122
which T cell helps make antibodies?
Helper T cell
123
what are the important characteristics of Regulatory T cells?
-downregulates the immune system and autoimmune diseases
124
what is special about T helper cell 17
-Th17 makes Il17 which is proinflammatory and over production of it will yield the production of autoimmune diseases
125
what are TH3 cells involved in?
- mucosal immunity and protection of mucosal surfaces
- accomplished by secreting TGF-beta and Il10 (immunosupressing)
- TGF-beta promotes class switch to IgA which doesnt usually activate complement system
- inhibits TH1 and TH2
126
what are natural killer T cells?
- heterogenous group of T cells
| - share common properties of NK and T cells
127
how are TCR and slg formed?
randomly
| not in response to any antigenic stimulation
128
what is a characteristic of early T cells?
what does this mean?
What happens as they mature
they are double positive hence they are composed of CD4+ and CD8+
once they mature they become either CD4 (Helpers) or CD8 (cytotoxic)
129
what are CD4 and CD8 involved in?
binding T cells to the MHC2 region of the MHC-peptide complex on the APC and MHC1 region of the MHC-peptide complex on the target cell while the TCR binds other parts
130
what is an effect of TCR and slg’s random selection
because 95% of the T cells produced by the thymus don't exit it same as for the B cells in the blood marrow
131
what happens if the MHC is too well recognized? not well enough?
in both cases they are deleted
132
how does T cell immunity work for viruses?
- virus enters dendritic cell
- TH1 cell comes and binds with MHC2-peptide as well as B7
- Tc cell comes along
- TH1 and Tc cell interact with the help of IL 2 and INF and destroys the cell
- MHC1 and TCR digest the virus
133
what happens when a virus enters the cell?
it will take over the cell’s total functioning and control it based on of its own needs
134
why is it possible in the proteosome to have an immune response even if MHC2 is lacking?
due to corepresentation (MHC2 gets bypassed in the process)
135
what is present in all antigens?
MHC2
136
what happens if a T cell does not recognize MHC 2 molecules?
they are negatively selected and their clone is destroyed
137
what happens if a T cell recognizes MHC2-self peptide complex molecules?
they are negatively selected and their clone is destroyed
138
what % OF Thymic lymphocytes recognize MHC2-SELF?
95%
139
what happens if a T cell recognizes MHC2-nonself peptide complex molecules?
positively selected
| peripheralized to the secondary lymphoid organs
140
how in immunological tolerance maintained in adults?
- ongoing thymic tolerance mechanisms for new T cells produced
- CTLA4 AND B1 inactivate the binding
