Body defence Flashcards
1
Q
define acute inflammation
A
an immediate, adaptive response with limited specificity caused by several noxious stimuli, such as infection and tissue damage (tissue necrosis).
only lasts a short period of time
2
Q
what is chronic inflammation
A
Your body continues sending inflammatory cells even when there is no outside danger. For example, in rheumatoid arthritis inflammatory cells and substances attack joint tissues leading to an inflammation that comes and goes and can cause severe damage to joints with pain and deformities.
3
Q
what is acute inflammation caused by
A
Acute inflammation is typically caused by injuries, like a sprained ankle, or by illnesses, like bacterial infections and common viruses
4
Q
5 signs of acute inflammation
A
heat redness swelling pain loss of function
5
Q
what is heat and redness also known as
A
hyperaemia (due to increased blood flow)
6
Q
what is exudate
A
swelling - fluid moving from the blood flow to interstitial caused by increased blood flow
7
Q
describe the vascular changes that happen during acute inflammation (vascular calibre, blood flow, vascular permeability)
A
vascular calibre: rapid transient (lasting only for a short time)vasoconstriction of arterioles followed by vasodilation
blood flow: initial reduction of blood flow by increased blood flow to the capillaries
vascular permeability: increased permeability of microvasculature
outpouring of protein rich fluid from the plasma - exudate
>hydrostatic pressure +
8
Q
describe inflammatory swelling
A
is oedema due to accumulation of exudate
exudate is: inflammatory extravascular fluid - protein rich
9
Q
describe “not” inflammatory swelling
A
is oedema due to accumulation of transudate
10
Q
define transudate
A
Transudate is an ultrafiltrate of plasma that contains few, if any, cells and does not contain large plasma proteins, such as fibrinogen. Transudate results from increased hydrostatic or reduced oncotic pressure.
11
Q
what is extravasation
A
where endothelial cells and leucocytes express mutually recognising adhesion molecules
Extravasation is the leakage of a fluid out of its container into the surrounding area, especially blood or blood cells from vessels. In the case of inflammation, it refers to the movement of white blood cells from the capillaries to the tissues surrounding them
12
Q
what is migration in terms of cellular events
A
Leucocytes move following concentration gradients of chemical and inflammatory mediators (chemotaxis)
13
Q
three stages of phagocytosis
A
recognition and adhesion
engulfment
killing or degradation
14
Q
define pus
A
a thick yellowish or greenish opaque liquid produced in infected tissue, consisting of dead white blood cells and bacteria with tissue debris and serum.
15
Q
define abscess
A
a swollen area within body tissue, containing an accumulation of pus.
16
Q
define empyema
A
the collection of pus in a cavity in the body, especially in the pleural cavity.
17
Q
three plasma mediators
A
coagulation system
kinin system
complement system
18
Q
three cell mediators
A
mast cells
basophils
platelets
19
Q
what are chemical mediators
A
endogenous (having an internal cause or origin.) chemical agent which takes an active part in the development of the inflammatory response.
20
Q
what is the coagulation system activated by
A
tissue damage
21
Q
end product of coagulation system
A
fibrin
22
Q
what is fibrin
A
an insoluble protein formed from fibrinogen during the clotting of blood. It forms a fibrous mesh that impedes the flow of blood.
23
Q
thrombin role in the coagulation system
A
increases leukocyte adhesion and fibroblast proliferation
24
Q
factor Xa role in the coagulation system
A
increases vascular permeability and leukocyte exudation
25
describe the kinin system
(poorly understood hormonal system with limited available research. It consists of blood proteins that play a role in inflammation, blood pressure control, coagulation and pain.)
• Activated through coagulation factor XII
end product is bradykinin causing vasodilation and triggering pain
26
what's an opsonin
extracellular proteins that, when bound to substances or cells, induce phagocytes to phagocytose the substances or cells with the opsonins bound. Thus, opsonins act as tags to label things in the body that should be phagocytosed by phagocytes.
27
describe the complement system
(The complement system, also known as complement cascade, is a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane.)
triggers expression of adhesion molecules on leucocytes
28
what is a vasoactive amine
A substance containing amino groups, such as histamine or serotonin, that acts on the blood vessels to alter their permeability or to cause vasodilation.
29
describe histamine'(what does it contain, what is it released in response to, what does it do)
contain basophils, mast cells and platelets
released into response to: physical injury, trauma, cold or heat
causes dilation of arterioles and increases vascular permeability of the venules
30
describe serotonin
contains platelets and enterchromaffin cells
| actions similar to those of histamine
31
what does arachidonic acid metabolite do as a cell mediator
prostaglandin, arteriolar dilatation and pain
32
what do cytokines and chemokines do as cell mediators
increased vascular permeability and chemotaxis
| Chemotaxis is the phenomenon by which cell movement is directed in response to an extracellular chemical gradient
33
what is chemotaxis
Chemotaxis is the movement of an organism or entity in response to a chemical stimulus.
34
what does nitric oxide do as a cell mediator
vasodilation
35
what does platelet activatin factor do as a cell mediator
platelet aggregation
increased vascular permeability
activation of leucocytes
36
what are leukocytes
the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders.
(leucocytes and leukocytes are the same thing)
37
7 systemic effects of inflammation
```
fever
malaise, lethargy, and sleepiness
pain
leucocytosis
tissue damage
swelling in a confined space
hyperpyrexia
```
38
what is hyperpyrexia
a condition where the body temperature goes above 106.7 degrees Fahrenheit (41.5 degrees Celsius) due to changes in the hypothalamus — the organ in the brain that regulates temperature. Hyperpyrexia is a life-threatening emergency that demands urgent medical attention.
39
how is a fever caused during inflammation
IL1, IL6 and TNF cause release of prostaglandins affecting the hypothalamic thermostat with temperature being set higher.
40
how is Malaise, lethargy and sleepiness caused during inflammation
Cytokines affecting the brain to reduce behaviour which could be counterproductive
41
what is leucocytosis
A higher-than-normal number of white blood cells is called leukocytosis. Leukocytes usually increase in number when they are doing their job, but there are some other conditions that can cause an increase.
42
what is fibrinous inflammation
fibrinogen exits the blood and accumulate as fibrin in extracellular space, due to increased vascular permeability or procoagulant stimuli (tumours)
43
what is suppurative inflammation
The process of pus formation, called suppuration, occurs when the agent that provoked the inflammation is difficult to eliminate. Pus is a viscous liquid that consists mostly of dead and dying neutrophils and bacteria, cellular debris, and fluid leaked from blood vessels.
44
what is purulent inflammation
Production of pus, comprising neutrophils, dead or alive, cellular debris and oedema
45
difference between suppurative and purulent inflammation
Both purulent and suppurative are used to describe pus formation. However, others employ purulent and suppurative in a more specific way: purulent is used to describe the pus forming in the affected area whereas suppurative is used to describe the pus oozing from the site of injury or infection
46
what is death due to severe local damage called
meningitis
47
what is death due to uncontrollable infection called
sepsis and shock
48
describe the process of acute inflammation in appendicitis
```
Acute appendicitis (AA) is a suppurative inflammatory process of the vermiform appendix and is the most common life-threatening surgical emergency in the pediatric age group.
(vermiform appendix: vermiform appendix is a narrow, worm-shaped structure that protrudes from the posteromedial aspect of the cecum, 2 cm (or less) below the insertion of the ileum into the cecum)
```
49
what is osteomyelitis
a bone infection
50
what is pathogenesis
is the process by which a disease or disorder develops
51
pathogenesis of chronic inflammation
often develops during the transition from acute inflammation to tissue repair. Chronic inflammation may also develop de novo in response to certain types of insults.
52
mechanism of chronic inflammation
adaptive immune responses can cause ongoing and excessive activation of innate immune cells.
53
morphology of chronic inflammation
fairly non-specific. However, the proportions of each cell type will vary depending on the condition. For example, Plasma cells are prevalent in rheumatoid arthritis, whereas in chronic gastritis, lymphocytes are typically more abundant.
54
outcome of chronic inflammation
your body's inflammatory response can eventually start damaging healthy cells, tissues, and organs. Over time, this can lead to DNA damage, tissue death, and internal scarring. All of these are linked to the development of several diseases, including: cancer.
55
diagnostic tests used to test for inflammation
Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are blood tests that can be used to check the levels of inflammation in your body.
56
how does ESR test for inflammation
The ESR rate increases as a result of any cause or focus of inflammation. When an inflammatory process is present, fibrinogen enters the blood in high amounts and causes red cells to stick to each other, which raises the ESR. Moderate elevations are common in active inflammatory diseases.
57
CRP test for inflammation
A high level of CRP in the blood can be a marker of inflammation. A wide variety of conditions can cause it, from an infection to cancer. High CRP levels can also indicate that there's inflammation in the arteries of the heart, which can mean a higher risk of heart attack.
58
Long-term diseases that doctors associate with inflammation
```
asthma
chronic peptic ulcer
tuberculosis
rheumatoid arthritis
periodontitis
ulcerative colitis
sinusitis
active hepatitis
```
59
what is granulomatous inflammation
pecial type of chronic inflammation characterised by often focal collections of macrophages, epithelioid cells and multinucleated giant cells.
Examples of noninfectious granulomatous diseases are sarcoidosis, Crohn's disease, berylliosis, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, pulmonary rheumatoid nodules, and aspiration of food and other particulate material into the lung.
60
how does tuberculosis cause chronic inflammationsis
This immune response to TB is described as a chronic granulomatous inflammation; caused by close interaction between Mtb bacilli and host immune agents at the infection site
61
what does fibrosis mean
thickening or scarring of the tissue.
62
what is regeneration of tissue
natural process of replacing or restoring damaged or missing cells, tissues, organs, and even entire body parts to full function in plants and animals
63
what is repair by fibrosis
Tissue repair is a protective response after injury, but repetitive or prolonged injury can lead to fibrosis, a pathological state of excessive scarring
64
liver fibrosis
the excessive accumulation of extracellular matrix proteins including collagen that occurs in most types of chronic liver diseases. Advanced liver fibrosis results in cirrhosis, liver failure, and portal hypertension and often requires liver transplantation.
65
what is healing by primary intention
is the healing that occurs when a clean laceration or a surgical incision is closed primarily with sutures, Steri-Strips, or skin adhesive.
66
what is healing by secondary intention
a wound will be left open (rather than being stitched together) and left to heal by itself, filling in and closing up naturally.
67
how does poor blood supply affect wound healing
The availability of oxygen (O2) to cells in the wound area and the presence of adequate blood flow are important factors to the healing process. Oxygen plays a critical role in the formation of collagen, the growth of new capillaries, and the control of infection.
68
how does steroid therapy affect wound healing
Glucocorticoids (corticosteroids) cause dehiscence (the splitting or bursting open of a pod or wound) of surgical incisions, increased risk of wound infection, and delayed healing of open wounds
69
how does diabetes mellitus affect wound healing
People with uncontrolled diabetes may develop poor circulation. As circulation slows down, blood moves more slowly, which makes it more difficult for the body to deliver nutrients to wounds. As a result, the injuries heal slowly, or may not heal at all.
70
how does poor nutrition affect wound healing
can delay healing and impair wound strength, making the wound more prone to breakdown. There is a significant body of evidence supporting the essential role of nutrition in wound healing.
71
what are decubitus ulcers
Bedsores — also called pressure ulcers and decubitus ulcers — are injuries to skin and underlying tissue resulting from prolonged pressure on the skin. Bedsores most often develop on skin that covers bony areas of the body, such as the heels, ankles, hips and tailbone
72
what are arterial ulcer
painful injuries in your skin caused by poor circulation. Arterial ulcers typically happen when blood is unable to flow into the lower extremities, like the legs and feet
73
what are venous ulcers
leg ulcers caused by problems with blood flow (circulation) in your leg veins. Normally, when you get a cut or scrape, your body's healing process starts working to close the wound.
74
what is granulation tissue
vascularised fibrous tissue that replaces the fibrin clot and is part of the repair process
75
what do granulomas do
destroy or isolate pathogens or foreign material but might cause tissue destruction
76
cell renewal proliferation
will replace the lost cells
77
cell renewal differentiation
will replace complex architectural structures
78
labile cells
cells that continuously multiply and divide throughout life. This continual division of labile cells allows them to reproduce new stem cells and replace functional cells that are lost in the body
79
what is angiogenesis
formation of new blood vessels
80
innate immune response
the innate immune response consists of physical, chemical and cellular defenses against pathogens. The main purpose of the innate immune response is to immediately prevent the spread and movement of foreign pathogens throughout the body.
81
What is adaptive immunity
Adaptive immunity/acquired immunity/specific immunity
- is specific to the pathogen presented.
- meant to attack non-self pathogens but can sometimes make errors and attack itself. When this happens, autoimmune diseases can develop (e.g., lupus, rheumatoid arthritis).
82
what count as pathogens
```
bacteria
viruses
fungi
single-cell Protozoa
multicellular parasites
```
83
what is an antigen
toxin or other foreign substance which induces a specific immune response in the body, especially the production of antibodies
84
cells involved in innate immune response
```
natural killer cells
macrophages
neutrophils
dendritic cells
mast cells
basophils
eosinophils
```
85
cells involved in adaptive immunity
T and B lymphocytes
86
what is autoimmunity
is the system of immune responses of an organism against its own healthy cells, tissues and other body normal constituents.
87
what is immunopathology
tissue damage due to excessive immune response
88
what is an allergy
mounting an immune response due to environmental material
89
what is immunodeficiency
lack of functional immune response
90
skins physical barrier description
multi-layered stratified squamous epithelium
| dead , cornified, non -nucleated cells bound in keratin
91
describe chemical barrier of skin
| secretions from sweat? secretions from sebaceous glands?
lacking water
secretions from sweat: lactic acid, alcohol,lysozyme
secretions from sebaceous glands: free fatty acids, wax
92
describe microbiological factor of skin
commensals (normal flora)
reduce nutrients and produce fatty acids
compete with pathogens
93
describe physical barrier of alimentary canal
peristalsis by the oesophagus
| desquamation (The shedding of the outer layers of the skin. )
94
describe mucus barrier of alimentary canal
sticky
| peristaltic waves
95
describe chemical barrier of alimentary canal
stomach acid (pH 2)
gastric enzymes
pancreatic enzymes
bile salts
96
urinary tract defences
physical barrier: resistant multi-layered epithelium
primary defence is flushing
low pH of urine
urinary stasis (cystitis)
97
vaginal epithelium defences
chemical/microbiological barriers
low pH during menstrual years
estrogen stimulates glucagon for normal flora
98
cornea/conjunctiva defences
blinking
| lysozyme and antibodies in tears
99
two mono nucleated leukocytes
monocytes and macrophages
100
three polymorphonucleated leukocytes
neutrophils
basophils
eosinophils
101
describe macrophages (monocytes)
sentinels of danger/ infection
a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection.
102
describe neutrophils
most abundant of all white blood cells (70%)
important in fighting early phases of bacterial infection
amoeboid movement (most common mode of locomotion in eukaryotic cells)
diapedesis (the passage of blood cells through the intact walls of the capillaries, typically accompanying inflammation.)
chemotaxis
phagocytosis
usually self-destruct after phagocytosis 5-25 cells or bacteria
average lifespan of a few days
103
what is an eosinophil
re a variety of white blood cells and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates
104
basic overview of interferon system
Interferons are proteins that are part of your natural defenses. They tell your immune system that germs or cancer cells are in your body. And they trigger killer immune cells to fight those invaders. Interferons got their name because they "interfere" with viruses and keep them from multiplying
105
NK (natural killer) cells
```
Natural killer (NK) cells are effector lymphocytes of the innate immune system that control several types of tumors and microbial infections by limiting their spread and subsequent tissue damage.
very short lived 7-8 hours
recycled by liver
```
106
what is humoral immunity
mediated by macromolecules (secreted antibodies, complement proteins, certain antimicrobial peptides)
located in extracellular fluid.
involves substances found in the humors (body fluids)
Humoral immunity is the process of adaptive immunity manifested by the production of antibodies by B lymphocytes. It develops in bone marrow. B cells may be triggered to proliferate into plasma cells. Plasma cells produce antibodies. Antibodies are produced when the antigen bonds the B cell receptor
107
what are immunoglobulins called when they've been secreted
antibodies
108
what is an antigen
any molecule that is recognised by, or specifically binds to, the antigen binding domain of an antigen receptor
109
what are endogenous antigens
they are synthesised within cells and can be self or non-self (e.g. from replicating virus after infection)
110
what are exogenous antigens
they are brought into the cell and can be self or non-self
| e.g. from phagocytosis of a bacterium or a diseased cell
111
what antigens can B cells and T cells recognise
B cells recognise any antigen
| T cells limited (only short linear amino acid sequences of peptides)
112
what is an antibody
a protein that binds specifically to a particular antigen
113
how do B cells recognise antigens
they recognise their related antigen in its native form
B cell receptor used in recognition can also be secreted to bind to antigen and initiate multiple effector functions such as phagocytosis, complement activation or neutralisation of receptors
114
basic structure of an antibody
Y formation made up of two light chains and two heavy chains
each light chain consists of one variable region and one constant region
each heavy chain consists of one variable region and multiple constant region domains
115
Fab in structure of antibodies
fragment antibody binding
116
fc in structure of antibodies
fragment crystallisable
117
five different classes of immunoglobulins (antibodies)
```
IgE
IgM
IgA
IgG
IgD
```
118
two immunoglobulin isotypes that appear as subclasses
IgG (IgG1, IgG2, IgG3, IgG4)
| IgA (IgA1, IgA2)
119
which immunoglobulin is secreted by plasma cells and released as a pentamer
IgM
120
which immunoglobulin is secreted across mucosal surfaces
IgA
121
properties of IgA
found in mucous, saliva, tears and breast milk
protects against pathogens
(Looks like a straight line?)
122
properties of IgD
| part of what receptor, activates what cells, what structure
part of the B cell receptor
activates basophils and mast cells
Y shape structure
123
Properties of IgE
| protects against, responsible for, what shape structure
protects against parasitic worms
responsible for allergic reactions
Y shape structure
124
properties of IgG
secreted by plasma cells in the blood
able to cross the placenta into the foetus
Y shape structure
125
properties of IgM
may be attached to the surface of the B cell or secreted into the blood
responsible for early stages of immunity
pentamer structure
126
which immunoglobulin is the smallest
IgG (Can get everywhere)
127
discuss transfer of maternal antibodies
immune system poorly developed at birth
mammals transfer antibodies via colostrum (the first secretion from the mammary glands after giving birth, rich in antibodies.) for the first 24-48hrs
gives protection for the first few months before production of own antibodies
IgG protects foetus
128
which antibodies are responsible for neutralisation of bacteria, viruses and toxins?
IgA, IgG and IgM
129
which antibodies are responsible for opsonisation ? describe it
IgA and IgG
antibody-coated bacterium binds to Fc receptors on cell surface
macrophage membrane surrounds bacterium
macrophage membrane fuses creating a membrane-bound vesicle , the phagosome
130
What is ADCC
antibody dependent cellular cytotoxicity
131
what antibody is responsible for ADCC - describe it
IgG
antibody binds antigens on the surface of target cells
Fc receptors on NK cells recognise bound antibody
cross linking of Fc receptors signals the NK cells to kill the target cells
target cell dies by apoptosis and/or membrane damage
(ADCC is A type of immune reaction in which a target cell or microbe is coated with antibodies and killed by certain types of white blood cells. )
132
describe activation of complement cascade by IgG
IgG molecules bind to antigens on bacterial surface
C1q binds to at least two IgG molecules
(the complement component 1q is a protein complex involved in the complement system, which is part of the innate immune system. C1q together with C1r and C1s form the C1 complex. Antibodies of the adaptive immune system can bind antigen, forming an antigen-antibody complex. )
133
Describe activation of complement cascade by IgM
pentameric IgM molecules binds to antigens on bacterial surfaces and adopt 'staple' form
C1q binds to IgM
(the complement component 1q is a protein complex involved in the complement system, which is part of the innate immune system. C1q together with C1r and C1s form the C1 complex. Antibodies of the adaptive immune system can bind antigen, forming an antigen-antibody complex. )
134
which antibody trigger mast cell activation
IgE
135
which antibody triggers eosinophil activation (Describe)
IgE
| helps to destroy multi-cellular parasites
136
describe isotope switching after activation (antibodies)
all newly formed B cells express monomeric IgM and IgDat the cell surface as receptors
following activation B cells undergo isotope switching in order to produce different types of antibodies
137
what is the primary immune response characterised by (think graph)
- lag phase - during which B cells undergo clonal selection in response to antigen, proliferate and differentiate into plasma cells or memory cells (typically 4-7 days)
- then an exponential increase in serum antibody levels
- peak in antibody level at 7-10 days followed by a decline in antibody levels
- initially all IgM secretion but some IgG produced late in the primary response
- formation of memory B cells
138
what does clonal expansions and B cell memory mean
that the immune response gets bigger on each encounter
139
what does isotype switching mean (in terms of antibodies)
initially IgM dominates the response, but that this is replaced by IgG
140
what does somatic mutation mean (in terms of antibodies)
definition: somatic mutation is a change in the DNA sequence of a somatic cell of a multicellular organism with dedicated reproductive cells; that is, any mutation that occurs in a cell other than a gamete, germ cell, or gametocyte
means that as the response develops the affinity of the antibody increases
141
what is the secondary immune response characterised by
- mediated by memory B cells formed in the primary immune response
- shorter lag phase than primary
- more antibody production than primary
- antibody is of higher affinity for antigen than in the primary (called affinity maturation)
- includes various isotopes in addition to IgM
142
define plasma cells
A type of immune cell that makes large amounts of a specific antibody. Plasma cells develop from B cells that have been activated. A plasma cell is a type of white blood cell. Also called plasmacyte
143
what are lymphocytes
clones
144
describe t cells
produced in bone marrow
| mature in thymus before entering the circulation
145
what are dendritic cells
professional antigen presenting cells (APCs) that present antigens to T cells
(take up fragments of microbes in inflamed tissue and then take them to the local lymph nodes too show them to T and b cells
146
describe when an APC and T cell come together
the membrane connecting them is folded
tcr( T cell receptor) does not bind to soluble antigen
it recognises peptide fragments of antigens presented by MHC molecules
147
MHC molecules??
major histocompatibility complex
| gene complex that codes for the molecules
148
cells that present MHC class I
all nucleated cells except
neurones
sperm cells
certain cells within placenta
149
cells that present MHC class II
APCs: (Antigen presenting cells)
dendritic cells
B cells
macrophages
150
3 different types of T cells
Th1 - t helper 1
Th2 - t helper 2
CTL - T cytotoxic
151
Describe TH1 (co receptor, antigen source and MHC binding class)
co receptor - CD4
antigen source - exogenous (synthesis outside)
MHC binding class II
152
Describe TH2
co receptor, antigen source and MHC binding class
Co receptor CD4
antigen source - exogenous (synthesis outside)
MHC binding class II
153
```
Describe CTL
(co receptor is, antigen source is, MHC binding class)
```
Cytotoxic T-lymphocyte.
```
Co receptor CD8
antigen source endogenous (synthesis within)
MHC binding class I
```
154
describe endogenous antigen MHC class I
MHC class I molecules (MHC-I) are cell surface recognition elements expressed on virtually all somatic cells. These molecules sample peptides generated within the cell and signal the cell's physiological state to effector cells of the immune system, both T lymphocytes and natural killer (NK) cells.
- cell infected by virus or bacteria or cancer cell
- newly made foreign / self proteins expressed within cytoplasm
- proteins ubiquitinated (form of post-translational modification in which the ubiquitin-protein is attached to a substrate protein) and broken downing peptide by proteosome
- peptides transported via to ER, complexed with MHC class I proteins , inserted into membrane
- recognised by CD8+ cytotoxic T cells
- activation of killer T Cells
155
describe exogenous antigen MHC Class II
The main function of major histocompatibility complex (MHC) class II molecules is to present processed antigens, which are derived primarily from exogenous sources, to CD4(+) T-lymphocytes. MHC class II molecules thereby are critical for the initiation of the antigen-specific immune response.
-extracellular antigens
- taken up by endocytosis by APCs
- degraded into peptides in a phagosome
-phagosomes fuse with MHC class II containing vesicles , complex with peptides, inserted into membrane
-recognised by CD4+ helper T cells
_activation of helper T cells
156
what do TH1 help fight against
intracellular bacteria
viruses
cancer
157
what do TH2 help fight against
extracellular bacteria
parasites
toxins
allergens
158
`what do cytokines do
alter behaviour of target cells
159
what do cytotoxins do
kill the target cell (by apoptosis)
160
impact of viral diseases on society
pandemics, epidemics etc
directed health impact - acute and chronic illness , death
indirect - loss of function(not working), loss of earnings, economic productivity, healthcare costs
161
UK viral emergencies
viral haemorrhagic fevers
rabies
MERS CoV
avian influenza A (Bird flu)
162
what is a virus particle ( virion) composed of
virus genome (nucleic acid) - DNA or RNA but not both
protein capsid (coat)
may possess an envelope
may include replicative enzymes
163
four principle criteria for classification of virus
nature of nucleic acid in virion (virus particle)
symmetry of capsid
presence or absence of envelope
dimensions of virion and capsid
164
typical lifecycle of enveloped virus
```
attachment
penetration - fusion or endocytosis
uncoating
genome replication - and gene expression
assembly
maturation
release
```
165
what is viral pathogenesis
process by which viral infection leads to disease
| virus doesn't want to harm host - its our immune system that hurts us
166
factors in viral pathogenesis
- portal of entry and course of infection (primary replication, systemic spread, secondary replication)
- cell/tissue tropism (the ability of a given virus to productively infect a particular cell (cellular tropism), tissue (tissue tropism) or host species (host tropism)
- cell/tissue damage - direct and indirect (lysis, host immune response)
167
virus and host factors that determine outcome of infection
virulent virus strain causes significant disease
avirulent or attenuated strain causes no or reduced disease
host factors - age, gender, immunity, immunosuppression, genetic susceptibility
168
types of transmission
direct - contact, droplets, aerosol
indirect - vehicle borne, fomites (objects or materials which are likely to carry infection, such as clothes, utensils, and furniture), vectors, airborne
resp. secretions, urine, vomit, blood, semen
169
two main mechanisms for intra-host viral spread
via blood stream and lymphatic system
| via nervous system
170
define viraemia
presence of virus in the blood
171
what's lymphadenopathy or adenopathy
disease of the lymph nodes where they are abnormal in size or consistency
172
what is viral tropism determined by
presence of cellular receptors
cellular proteins that regulate viral replication
cellular proteins that regulate viral transcription
cellular proteins which "activate" viruses
accessibility of susceptible cells
173
describe primary infection of herpes simplex virus
usually colds sores
sore throat
fever
rarely - encephalitis (inflammation of the brain)
174
describe the latent infection of herpes simplex
asymptomatic - no virus produced
| viral DNA resides in sensory cells of trigeminal nerve ganglion
175
describe the reactivation phase of herpes simplex
virus replicates and travels down sensory nerve fibre to infect epithelial cells around the nose and mouth
176
Basic concept of vaccination
Vaccination: The act of introducing a vaccine into the body to produce protection from a specific disease. Immunization: A process by which a person becomes protected against a disease through vaccination. This term is often used interchangeably with vaccination or inoculation.
177
what is meant by herd immunity
form of indirect protection from infectious disease that can occur with some diseases when a sufficient percentage of a population has become immune to an infection, whether through previous infections or vaccination, thereby reducing the likelihood of infection for individuals who lack immunity
178
what is a live vaccine
made from a virus that has been weakened so it does not cause the disease the virus usually causes. A live virus vaccine helps the body's immune system recognize and fight infections caused by the non-weakened form of the virus.
179
what is an attenuated vaccine
vaccine created by reducing the virulence of a pathogen, but still keeping it viable. Attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent. These vaccines contrast to those produced by "killing" the virus.
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what is a subunit vaccine
A subunit vaccine is a vaccine that contains purified parts of the pathogen that are antigenic, or necessary to elicit a protective immune response.
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define bacteria
a member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organized nucleus, including some that can cause disease.
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define virus
.
an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host
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define eukaryote
an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus. Eukaryotes include all living organisms other than the eubacteria and archaea.
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define parasite
an organism that lives in or on an organism of another species (its host) and benefits by deriving nutrients at the other's expense
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define prion
Prions are misfolded proteins with the ability to transmit their misfolded shape onto normal variants of the same protein. They characterize several fatal and transmissible neurodegenerative diseases in humans and many other animals.
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define infection
The invasion and growth of germs in the body. The germs may be bacteria, viruses, yeast, fungi, or other microorganisms. Infections can begin anywhere in the body and may spread all through it. An infection can cause fever and other health problems, depending on where it occurs in the body.
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define contagious
spread from one person or organism to another, typically by direct contact.
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define comensal pathogen
Living in a relationship in which one organism derives food or other benefits from another organism without hurting or helping it. Commensal bacteria are part of the normal flora in the mouth.
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define virulence
is a pathogen's or microorganism's ability to cause damage to a host
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define microbiome
the microorganisms in a particular environment (including the body or a part of the body).
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Difference in structure between eukaryotic and prokaryotic cells
include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal DNA.
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risks of antimicrobial use
Increased antimicrobial resistance is the cause of severe infections, complications, longer hospital stays and increased mortality. Overprescribing of antibiotics is associated with an increased risk of adverse effects, more frequent re-attendance and increased medicalization of self-limiting conditions.
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what is a coccus
any spherical or roughly spherical bacterium.
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what is a bacilli
bacillus, or bacilliform bacterium, is a rod-shaped bacterium or archaeon.
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what is a vibrios
water-borne bacterium of a group that includes some pathogenic kinds that cause cholera, gastroenteritis, and septicaemia.
curved rod-shape
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what is a spirochetes
a flexible spirally twisted bacterium, especially one that causes syphilis.
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what is colonisation
colonization is the presence of bacteria on a body surface (like on the skin, mouth, intestines or airway) without causing disease in the person
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what is contamination
the presence of a constituent, impurity, or some other undesirable element that spoils, corrupts, infects, makes unfit, or makes inferior a material, physical body, natural environment, workplace, etc
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difference between endo and ectoparasites
Endoparasites live inside an organism, and ectoparasites live on the surface of the host. Parasites can be carnivorous if living with animals or herbivorous if living with plants.
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define incubation period
Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent
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define infectious period
is the time interval during which a host is infectious, i.e. capable of directly or indirectly transmitting pathogenic infectious agents or pathogens to another susceptible host
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define transmissibility
the quality of a disease or trait being able to be passed on from one person or organism to another.
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how does Clostridium tetani form endopsores that resist extremes of temperature
The cortex is what makes the endospore so resistant to temperature. The cortex contains an inner membrane known as the core. The inner membrane that surrounds this core leads to the endospore's resistance against UV light and harsh chemicals that would normally destroy microbes.
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transmission of meningococcus
people spread meningococcal bacteria to other people by sharing respiratory and throat secretions (saliva or spit).
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explain term sepsis
the body's extreme response to an infection. It is a life-threatening medical emergency. Sepsis happens when an infection you already have triggers a chain reaction throughout your body. Infections that lead to sepsis most often start in the lung, urinary tract, skin, or gastrointestinal tract.
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basic principle of gram staining
involves the ability of the bacterial cell wall to retain the crystal violet dye during solvent treatment.
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what does hypersensitivity mean
describes an adverse reaction to an antigen
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Four types of hypersensitivity
Type I - IgE mediated
type II - IgG mediated
Type III - immune complex mediated
Type IV- T cell mediated
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Factors affecting Th1 phenotype
presence of older siblings
early exposure to day care
TB, measles, or hepatitis A infection
rural environment
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Factors affecting Th2 phenotype
```
widespread use of antibiotics
western lifestyle
urban environment
diet
sensitisation to house dust mites and cockroaches
```
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Describe initiating event of Type I hypersensitivity
```
IgE dependent
soluble antigen (allergen)
triggers IgE response
subsequent antigen exposure leads to interaction with IgE on mast cells
IgE bound by FcRe
mast cell/basophil degranulation
```
example of this response is anaphylaxis
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what is type II hypersensitivity divided into
IIa - cytotoxic
| IIb- cell stimulating/signalling
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Type IIa hypersensitivity
IgG antibody interacting with cell surface antigen
antigen cell associated
may be happen (a small molecule which, when combined with a larger carrier such as a protein, can elicit the production of antibodies which bind specifically to it (in the free or combined state).) interaction
binding of IgG leads to lysis of target cells
complement mediated
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type IIb hypersensitivity
| what immunoglobulin mediated?
cell stimulating reactions involving altered cell function
IgG mediated
IgG interacts with cell surface receptor involved in cell signalling
antigen cell associated
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Type III hypersensitivity
```
antigen - antibody complexes (IgG)
antigen soluble or matrix associated
deposit in microvasculature
complement activation
tissue inflammation
```
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Type IV hypersensitivity divided into
Th1
Th2
cytotoxic
Ivd
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Type IV Th1 hypersensitivity
```
classical delayed type hypersensitivity
antigen presentation to sensitised CD4 Th1 cells
soluble antigen
Th1 cytokine production and release
macrophage activation
macrophage rich antibody response
```
contact dermatitis
drug allergies
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TypeIV th2 hypersensitivity
cell-mediated eosinophilic hypersensitivity (chronic allergic inflammation)
antigen presented to sensitised predominately CD4 Th2 cells
soluble antigen
eosinophil rich inflammatory response
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examples of Type IV th2 hypersensitivity
chronic asthma
chronic allergic rhinitis
topic eczema
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Type IV cytotoxic hypersensitivity
antigen presented to sensitised CD8 T cells
antigen cell associated
cytotoxicity - perforin
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examples of Type IV cytotoxic hypersensitivity
early onset type 1 diabetes mellitus
graft rejection
some drug reactions
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describe autoimmune disease
adaptive immune system recognises self antigen as harmful and amounts an immune attack
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describe auto-inflammatory disease
results from over activity of the innate system
may be activated by triggers but genetic mutations can cause triggers
Innate: from when you were born
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what happens in auto-inflammatory disease
raised inflammatory markers
| absence of infection
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what is iatrogenic anaphylaxis
drug induced anaphylaxis
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organism for common cold, pneumonia, influenza
cold - rhinovirus
pneumonia - Streptococcus pneumoniae
influenza - Orthomyxovirus genus.
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transmission of common cold, pneumonia, influenza
cold- air, close contact, contact with stool, respiratory secretions
pneumonia - cough, sneezes, respiratory secretions
influenza - droplets
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how to distinguish between influenza and pnuemonia
The flu usually comes on suddenly, while pneumonia takes longer to develop and can be a complication from the flu.
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is IgE found in early infection
no
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In an indirect ELISA is the enzyme is linked to a secondary antibody?
yes
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5mg/ml is diluted 5 fold 3 times
0.04
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Cell surface markers present on t helper cells
TcR
| CD4
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What is the single most important requirement for samples to be analyzed on a flow cytometer?
cells must be in single cell suspension
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role of disinfectants in killing bacteria
They kill off the bacteria by causing the proteins to become damaged and the outer layers of the bacteria cell to rupture. The DNA material subsequently leaks out.
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does toilet paper act as an effective barrier to bacterial transmission
no
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Direct ELISA
○ Uses monoclonal antibodies to detect presence of particular antigen in a sample
○ Can be used to measure amount of antigen labelled primary antibody
§ In this case antigen is usually bound to the well of an ELISA plate
§ After labelled antibody binds to the antigen it can be detected through an enzyme reaction
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Indirect ELISA
○ Used to determine presence of specific antibody (eg. Antibodies to HIV) in a specimen such as serum
○ Involves at least two different antibodies
§ Primary antibody will be specific for antigen of interest but is not linked to an enzyme
§ Secondary antibody specific for primaru antibody will be conjugated (covalently linked) to an enzyme and it is therefore possible to quantify how much primary antibody has bound to the antigen of interest
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Capture ELISA
○ Capture ELISA or 'sandwich' ELISA variation on the indirect method
§ Allows complex antigen samples (such as serum) to be analysed for presence of specific antigen or the presence of an antibody against a specific infection
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analysing ELISA plates
* Antibody specific to virus antigen will bind to the antigen and any unbound antibody is washed away
* Second reaction is performed where anti-human immunoglobulin that is coupled to an enzyme (enzyme-linked antibody) is added and binds to primary antibody and any unbound antibody is washed away
* Substrate is then added and enzyme acts off this substrate causing a colour change, the stronger the antibody response the stronger the colour
* Plate is 'read' in a plate reader using light with a wavelength of 405nm and the detector will report the absorbance of light as a numerical (optical density) OD405 reading
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flow cytometry
technology that rapidly analyzes single cells or particles as they flow past single or multiple lasers while suspended in a buffered salt-based solution. Each particle is analyzed for visible light scatter and one or multiple fluorescence parameters. ... Light scatter is independent of fluorescence.
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what does perforin do
causes pores to form in target cells membrane
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what do granzymes do
enter cell and induce apoptosis seen as DNA fragmentation
