Immunology Flashcards
1
Q
Immunity may be _ or _
A
Natural or acquired
2
Q
What is immunity
A
Immunity refers to all the properties of the host that confer resistance to a specific infectious agent. That is to say that immunity is non susceptible to the invasive pathogenic effects of foreign microorganisms or to the toxic effects of antigenic substances
3
Q
What are the physiological mechanisms of an immune response
A
- To distinguish foreign material from self
- To neutralize, eliminate and metabolize that which is foreign by the physiological mechanisms of immune response
4
Q
Acquired immunity may be _ or _
A
Passive or active
5
Q
Another name for natural immunity
A
Innate immunity
6
Q
What is the 1st line of defense
A
Skin, mucosal membrane, normal microbiota : Physical barrier, lymphoid cells, Antimicrobial molecules
7
Q
How many lines of defense are there
A
3
8
Q
What is the 2nd line of defense
A
Innate immune system: macrophages (phagocytic WBC), Natural Killer cells, Neutrophils, Complement, , Cytokines (inflammation,fever)
9
Q
What is the 3rd line of defense
A
Adaptive immune system: Tcells, Bcells, Antibodies, Cytokins
10
Q
Comment on the epidermis of the skin as a first line of defense
A
It forms a physical barrier to the entrance of microbes
11
Q
Comment on mucous membrane as a first line of defense
A
Inhibits the entrance of many microbes, but not as effective as intact skin
12
Q
Comment on the function of mucus as a first line of defense
A
Traps microbes in respiratory tract and GIT
13
Q
Comment of lacrimal apparatus as a first line of defense
A
Tears produced from the gland, dilute and wash away irritating substances and microbes
14
Q
Comment on saliva as a first line of defense
A
Washes microbes from surfaces of teeth and mucous membranes of mouth
15
Q
Comment on hairs as a first line of defense
A
Filler out microbes and dust in nose
16
Q
Comment on cilia as a first line of defense
A
Together with mucus, trap and move mic-bes and lust from upper respiratory tract.
17
Q
Comment on epiglottitis as a first line of defense
A
Prevents microbes from entering lower respiratory tract
18
Q
Comment on urine as a first line of defense
A
Washes microbes from urethra,
19
Q
Comment on vaginal secretions as a first line of defense
A
Move microbes out of female reproductive tract
20
Q
Comment on defecation and vomiting as a first line of defense
A
Expel microbes from body
21
Q
What is innate immunity
A
Also called natural immunity, it is the type of immunity which is not acquired through previous contact with the infectious agent (or with a related species). Innate immunity response is non-specific and rapid, can affect a wide range of pathogen types and also triggers the development of acquired immunity.
22
Q
What are some characteristics of innate immunity
A
- It is non specific and rapid
- It can affect a wide range of pathogen types
- It triggers the development of subsequent adaptive immunity
- Each pathogen is treated the same way
- There is no immunological memory of the pathogen encounter
23
Q
What is inflammation
A
This is an immunological response characterized by an increased migration of immune cells to a site of infection. Innate immune cells detect pathogens that bypass the physical barrier, by detecting markers on them, which triggers the secretion of signaling molecules that attract other immune cells to help convert the infection.
24
Q
differences between innate immunity and adaptive immunity
A
- Innate immunity is present at birth and fights infection even without prior exposure to the pathogen, WHILE. Adaptive immunity may take a few days/weeks to become effective.
- Innate immunity provides a non-specific response that acts
against a broad range of different pathogens. WHILE. Adaptive immunity provides a highly specific response, meaning it has the ability to recognize specific foreign antigen - Innate immunity Recognizes pathogens but no immunological memory. WHILE. Adaptive immunity recognizes and destroys pathogens, and also retains the memory of that encounter (immunological memory)
- Innate immunity Activates further immune responses, specifically, adaptive immunity. WHILE. Adaptive immunity such as T-cells and B-cells, can only recognize presented antigens by Antigen Presenting Cells (APCs), a type of innate immune cell
- Innate immunity is complex and comprises biochemical and cellular pathways whose function is to recognize and remove invading pathogens. WHILE. Adaptive immunity focuses mainly on the production and actions of the T-cells nd the B-cells
25
dendritic cells, macrophages, mast cells and neutrophils are common in what way
they are all phagocytes
26
what is a phagocyte
A phagocyte is a type of innate immune cell that ingests and degrades pathogens.
27
In order to ingest and degrade pathogens, phagocytes ...
phagocytes express receptors that detect pathogen-associated molecular patterns (PAMPs).
PAMPs are molecular structures that are not present in vertebrates (e.g. mammals and birds) but are found on microorganisms.
The presence of PAMPs allows innate immune cells to recognize pathogens as 'non-self'
Toll-like receptors allow cells of the innate immune system to detect Toll-like receptors (TLRs) are a family of pattern-recognition receptors that detect pathogens via PAMPs.
28
what is the significance of the presence of PAMP
it allows immune cells to differentiate self from non-self (pathogens)
29
What does PAMP ancronyme
Pathogen-Associated Molecular Patterns
30
are PAMPs present in vertebrates
No, just on microorganisms
31
What does APC ancronyme
antigen presenting cells
32
what does TLR ancronyme
Toll-Like Receptors
33
what are the TLRs
They are a family of pattern-recognition receptors that detect pathogens via PAMPs.
34
What is TNF-a (alpha)
Tissue Necrosis Factor- alpha
35
describe the neutrophils
They are Granular leukocytes. They are the most abundant leukocytes in blood (4-10 x 109/L), upon infection production (in bone marrow) increases rapidly (up to 20 x 109/L) and stimulated by CSF secreted by many cell types
36
describe the basophils
release histamine, other mediators of inflammation, vesicles bind basic dyes
37
describe the eosinophils
phagocytic, attack parasites with toxic proteins, role in alergic reactions (astma) and in antitumor defens
38
describe the dendritic cells
produce cytokines to recruit leukocytes and initiate adaptive immune response; major function is antigen displa
39
what is the major function of the dendritic cells
antigen display
40
what are the mast cells
They are tissue residing; filled with cytoplasmic granules containing histamine, heparin, prostaglandins and proteolytic enzymes; important for helminth infestation and allergies
41
what are the macrophages
monocytes become actively phagocytic macrophages when stimulated via infection, injury; production of cytokines to activate leukocytes; secrete growth factors and enzymes to repair injured tissue
42
what are the natural killer cells
recognize and destroy cells with features of tumor cells, cells with intracellular pathogen
43
what proteins send signals between cells to coordinate and immune response
cytokines
44
what are some important cytokines secreted by macrophages
-Tissue necrosis factor - Alpha
-Interleukin- I Beta
-Interleukin- 6
45
where are cytokines secreted from
They are secreted from the cell that detected the PAMP (Pathogen Associated Molecular proteins). Such as:
-Macrophages
-Neutrophils
-Monocytes
-Mast cells
-Dendritic cells
46
what cells detect cytokines
-Other immune cells such as macrophages, neutrophils and dendritic cells
-Non-immune cells such as endothelial cells
47
Comment on the process of immune signaling
-When a Toll-Like Receptor (TLR) is activated by binding to a PAMP (Pathogen associated Molecular Protein), signaling cascade sends a message to the cell nucleus to turn on certain genes that produce cytokines, such as: Tissue necrosis factor - Alpha, Interleukin- I Beta, Interleukin- 6.
-The cytokines are produced by the cells that detects the PAMP, FOR EXAMPLE: neutrophils, monocytes, macrophages, mast cells, dendritic cells.
-The cytokines can be detected by other immune cells: Immune cells (macrophages, neutrophils, dendritic cells) and non-immune cells (endothelial cells)
-The cytokines instruct immune cells to fight the infection. They are produce in response to stimuli that signal information. e.g antibodies, antigens, PAMPs
48
function of TNF-alpha
TNF-alpha acts on vascular walls to allow the entry of cells, complement and antibodies into the tissues to help contain the infection
49
Interleukin-1 Beta function?
it helps the immune cells to leave the blood and enter the tissues, it also activates the cells of the adaptive immune system (lymphocytes).
50
Interleukin-6 function
It activates lymphocytes and increases production of antibodies
51
how many proteins are of the coplement system
>30
52
what are some major complement proteins you know
C5a, C3a, C3b
53
what are the functions of the complement system
-Protection against infection
-Regulation of inflammatory processes
-Removal of damaged or altered cells
-Regulating adaptive immune responses
-Sending of danger signals throughout the body
-Activation of adaptive immunity
54
what is the complement system
The complement is a system of interacting protein molecules that aids in the removal of pathogens from an animal and forms an important component of innate immunity.
Functions of the complement
-Protection against infection
-Regulation of inflammatory processes
-Removal of damaged or altered cells
-Regulating adaptive immune responses
-Sending of danger signals throughout the body
-Activation of adaptive immunity
It is composed of > 30 proteins, including C5a, C3a and C3b.
3 pathways trigger an activation cascade and the pathogen
surface is a key site where complement activation occurs.
55
what is the site of complement activation
the pathogen surface
56
what are the 3 pathways of complement action
1) Enhance phagocytosis (opsonization) — C3b attaches to the cell surface of microorganisms to flag them for destruction by phagocytes;
2) Initiate inflammation C5a and C3a attract and activate neutrophils and mast cells and enhance TIR-induced production of proinflammatory cytokines;
3) Kill microbes the membrane attack complex (MAC) creates pores in cell membranes to kill bacteria
57
what is MAC
Membrane Attack Complex
58
explain the opsonization pathway of the complement
1) Enhance phagocytosis (opsonization) — C3b attaches to the cell surface of microorganisms to flag them for destruction by phagocytes;
59
explain the innate inflammation pathway of the complement system
Initiate inflammation------ C5a and C3a attract and activate neutrophils and mast cells and enhance TIR-induced production of proinflammatory cytokines;
60
explain the killer microbes pathway of the complement system
Kill microbes---- the membrane attack complex (MAC) creates pores in cell membranes to kill bacteria
61
what are the innate immunity response to infection
-Phagocytosis
-Inflammation
62
Comment on phagocytosis
-When a pathogen is detected, the phagocyte extends itself around the pathogen, taking the pathogen into an internal compartment inside the phagocyte, in a process termed phagocytosis.
-Phagocytes produce a number of toxic products that kill ingested pathogens:
-Some phagocytes contain primary granules which release antimicrobial peptides and protease enzymes onto the pathogen, which have widespread activity against different pathogens.
-The pathogens are digested by these toxic products in the intracellular compartment, and the broken-down products are then released from the phagocytes.
-During phagocytosis, the phagocyte undergoes a period of increased oxygen consumption and during this time enzymes are activated to produce reactive oxygen species, which are also toxic to the ingested bacteria.
-Also, phagocytes become activated by pathogens causing them to release cytokines, which signal to other immune cells for the destruction of pathogens.
63
what are the ways phagocytes destroy pathogens
-Some phagocytes contain primary granules which release antimicrobial peptides and protease enzymes onto the pathogen, which have widespread activity against different pathogens.
-The pathogens are digested by these toxic products in the intracellular compartment, and the broken-down products are then released from the phagocytes.
-During phagocytosis, the phagocyte undergoes a period of increased oxygen consumption and during this time enzymes are activated to produce reactive oxygen species, which are also toxic to the ingested bacteria.
-Also, phagocytes become activated by pathogens causing them to release cytokines, which signal to other immune cells for the destruction of pathogens.
64
The primary granules in the phagocytes secrete
-antimicrobial peptides,
-protease enzymes.
65
why do phagocytes go through a period of high oxygen consumption
It is because, during this time, enzymes are activated to produce reactive oxygen species which are also toxic to bacteria.
66
comment on inflammation
-The detection of PAMPs on pathogens by TLRs on phagocytes initiates a signalling cascade that results in the phagocyte secreting cytokines.
-Cytokines are responsible for the process known as inflammation, which helps more immune cells reach the site of infection in order to increase the strength of the immune assault against the infecting pathogen.
-Cytokines move through the tissues and cause changes to the cells that make up the blood vessel walls, known as endothelial cells.
-Blood vessels dilate and become leaky and express adhesion molecules on their surface.
-Immune cells bind to the adhesion molecules and then squeeze through the gaps in blood vessel walls to enter the tissues.
-Once in the tissues, immune cells follow a type of cytokine, called chemokines, which lead the cells to the focus of infection.
-This influx of immune cells to the site of infection produces the characteristic signs of inflammation; redness, swelling, heat and pain.
-Neutrophils arrive at the infection site first, followed by monocytes and immature dendritic cells (DCs).
-Once there, certain chemokines and complement proteins can cause activation of these immune cells. The activated immune cells are equipped to fight the infection through phagocytosis.
67
once in the tissues, immune cells follow ___ type of cytokines to the focus of the infection
chemokines
68
what are the characteristic signs of inflammation
-redness
-swelling heat
-pain
69
what cells reach the site of infection first (in order)
Neutrophils> Monocytes> Immature dendritic cells
70
what initiates the inflammation process
detection of PAMPs on Pathogens by TLRs on phagocytes
71
What is natural/ innate immunity
It is that type of immunity which is not acquired through previous contact with the infectious agent (or with a related species). Little is known about the mechanisms responsible for this form of resistance.
72
What is species immunity under natural/ innate immunity
A given pathogenic microorganism is often capable of producing disease in one animal species but not in another e.g the bacillus of avian tuberculosis causes disease in birds but almost never in human.
73
what is racial basis of immunity under natural/innate immunity
Within one animal species there may be marked racial and genetic differences in susceptibility e.g. person with sickle cell anemia are highly resistant to Plasmodium falciporum infection.
74
what is individual resistance under natural/innate immunity
As with biologic phenomena, resistance to infection varies with different individuals of the same species and race, following a distribution curve for the host population.
75
what is 'differences due to age' under natural/innate immunity
In general, the very young and the elderly are more susceptible to bacterial disease than person in other age groups. However, resistance to tuberculosis is higher at 5-15 years than before or after. Many age differences in specific infections can be related to physiologic factors
76
what is passive immunity
Passive immunity is a state of relative temporary insusceptibility to an infectious agent that has been induced by the administration of antibodies against that agent which have been formed in another host rather than formed actively by individual himself
77
why does passive immunity last for a short time
Passive protection lasts only a short time, usually a few weeks at most because the antibody molecules are decaying steadily while no new ones are being formed.
78
what kind of infections are passive immunity least effective
Invasive bacterial infection
79
give examples of passive immunity
-When an illness is largely attributed to a toxin (e.g. diphtheria, tetanus, botulism), the passive administration of antitoxin is of the greatest use because large amount of antitoxins can be made immediately available for neutralization of the toxin.
-In certain virus infections (e.g. measles, infectious hepatitis), the administration of specific antibodies (such as human pooled gamma globulin) during the incubation period may result in prevention or modification of the clinical disease
-Passive immunity resulting from the uterus transfer to the fetus of antibodies formed earlier in the mother protects the newborn child . during the first months of life against some coming infections.
-This passive immunity (acquired from the mother's blood) may be reinforced by antibodies taken up by the child in mother's milk (particular colostrums), but that immunity vanish at age 4-6 months.
80
comment on passive immunity for toxins
When an illness is largely attributed to a toxin (e.g. diphtheria, tetanus, botulism), the passive administration of antitoxin is of the greatest use because large amount of antitoxins can be made immediately available for neutralization of the toxin.
81
comment on passive immunity for viral infections
In certain virus infections (e.g. measles, infectious hepatitis), the administration of specific antibodies (such as human pooled gamma globulin) during the incubation period may result in prevention or modification of the clinical disease
82
comment on passive immunity from uteral transfer
Passive immunity resulting from the uterus transfer to the fetus of antibodies formed earlier in the mother protects the newborn child . during the first months of life against some coming infections.
83
comment on passive immunity from breast milk
This passive immunity (acquired from the mother's blood) may be reinforced by antibodies taken up by the child in mother's milk (particular colostrums), but that immunity vanish at age 4-6 months.
84
immunity obtained from colostrum last for how long
4-6 months
85
what is active immunity
Active immunity is a state of resistance built up in an individual following effective contact with foreign antigens e.g. microorganisms or their products.
-'Effective contact' may consist of clinical or subclinical infection, injection with live or killed microorganisms or their antigens, or absorption of bacterial products
86
the effective contact of active immunity consists of:
-clinical or subclinical infection,
-injection with live or killed microorganisms or their antigens, -absorption of bacteria? products (e.g. toxins, toxoids).
87
list differences between active and passive immunity
1. **Definition:** Active immunity is the immunity that develops in response to an antigen, while passive immunity is the immunity that is acquired from another source.
2. **Source of immunity:** Active immunity is acquired through exposure to an antigen, while passive immunity is acquired through the transfer of antibodies from another individual or animal.
3. **Duration of immunity:** Active immunity provides long-lasting protection, while passive immunity provides temporary protection.
4. **Onset of immunity:** Active immunity takes time to develop, while passive immunity provides immediate protection.
5. **Types of immunity:** Active immunity can be naturally acquired through infection or artificially acquired through vaccination, while passive immunity can be naturally acquired through placental transfer or artificially acquired through injection of antibodies.
6. **Memory response:** Active immunity results in the production of memory cells, which provide long-term protection against future infections, while passive immunity does not result in the production of memory cells.
7. **Specificity of immunity:** Active immunity provides specific protection against a particular antigen, while passive immunity provides non-specific protection against a range of antigens.
8. **Degree of protection:** Active immunity provides a higher degree of protection than passive immunity.
88
what disorders exhibit antibody formation dysfunction
- B.cell deficiency
- T cell dysfunction
- Aggamaglibulinemia
89
What is humoral immunity
-Active production of antibodies against antigens of microorganism or their products.
-Antibody formation is disturbed in certain individual with agammaglobulinemia, B cell deficiency or T cell dysfunction.
90
what is cellular immunity
-Although antibodies arise in response to foreign bodies, they play a role in the defense in an individual from invading cells.
-In this case circulating thymus dependent cells recognize materials and initiate a chain of responses that include:
-mononuclear inflammatory reactions
-cytotoxic destruction of invading cells (microbial graft of neoplastic)
-activation of cytotoxic macrophages
-Delayed hypersensitivity to reactions in tissues
91
what cells recognize foriegn bodies and initiate a chain of responses?
thymus dependent cells (T cells basically)
92
what include the chain of responses initiated by the thymus dependent cells
-mononuclear inflammatory reactions
-cytotoxic destruction of invading cells (microbial graft of neoplastic)
-activation of cytotoxic macrophages
-Delayed hypersensitivity to reactions in tissues
