Chapter 8 - Infection and Defects in Mechanisms of Defense Flashcards
1
Q
Communicability
A
ability to spread from one individual to others and cause disease
2
Q
Infectivity
A
ability of a pathogen to invade and multiply in a host
3
Q
Infectivity involves a_______, e_______, d_________
A
-attachment
-escape of phagocytes
-dissemination (spread)
4
Q
Virulence
A
severity or harmfulness of a disease or poison
5
Q
Toxigenicity
A
ability to produce toxins
6
Q
What do toxins influence?
A
a pathogen’s virulence
7
Q
Portal of Entry
A
route by which a pathogen infects the host
8
Q
What are some mechanisms of portal of entry?
A
-direct contact
-inhalation
-ingestion
-animal or insect bite
9
Q
Is the DNA in a prokaryote cell enclosed in a nucleus?
A
no, it only has a nucleoid
10
Q
Are prokaryotes aerobic or anaerobic?
A
they can be either depending on the species
11
Q
Are gram-positive or gram-negative bacteria more dangerous?
A
gram-negative due to their outer membrane and porin channels which make them more difficult to defeat
12
Q
Staphylococcus aureus is a common n______ infection
A
nosocomial
13
Q
Where are staphylococcus aureus housed as normal microbiota?
A
nasal passages and skin
14
Q
S. aureus produces a protein that blocks…
A
compliment attack
15
Q
How does S. aureus avoid innate immunity?
A
producing inhibitors that avoid recognition by the immune system
16
Q
What enzyme does S. aureus resist when engulfed by a phagocyte? How?
A
resists Lysozyme by changing the chemistry of their cell walls
17
Q
S. aureus resists the action of many of what kind of drugs?
A
antibiotics
18
Q
Exotoxins are released from ____ the pathogen
A
inside
19
Q
Endotoxins are released from ______ the pathogen.
A
outside, specifically the outer capsule
20
Q
What are exotoxins?
A
enzymes that damage host cell plasma membranes or inactivate critical protein synthesis enzymes
21
Q
What do endotoxins activate? What do they produce?
A
they activate the immune system and produce fever
22
Q
Bacteremia and septicemia are a result of the failure of ______ _________
A
defense mechanisms
23
Q
Bacteremia
A
presence of bacteria in the blood
24
Q
Septicemia
A
growth of bacteria in the blood
25
What two systems that start with "C" are activated by endotoxins?
complement and clotting systems
26
Endotoxins increase capillary permeability which leads to...
large volumes of plasma leaking into surrounding tissue and thus HYPOTENSION
27
What is the most common cause of pain or distress in humans?
viral disease
28
Viruses must _____ the host cell to replicate
enter
29
What is the structure of a virus?
it is neither a eukaryote or prokaryote and is just DNA or RNA surrounded by a capsid or envelope
30
Viruses are self-limiting meaning...
they resolve spontaneously without treatment or intervention
31
How are viruses transmitted?
-aerosol
-blood
-sex
-vector (tick, mosquito, etc.)
32
Viruses have cytopathic effects meaning...
they cause damage to living cells
33
Viruses inhibit host cell DNA or RNA _______
synthesis
34
How do viruses kill cells?
release lysosomes into the cell
35
Viruses can cause the _____ of host cells into multicellular giant cells
fusion
36
Viruses can cause the alteration of host cell antigen properties causing the immune system to attack...
its own cells
37
Can viruses cause cancer?
yes, they can transform host cells into cancerous cells
38
Why do viruses need host cells to replicate?
need to use the host cell resources
39
What is influenza?
a highly contagious viral infection of the respiratory passages
40
Influenza has the ability to produce antigenic variation meaning...
ability to change viral antigen spikes yearly
41
Fungi
are large eukaryotes with thick, rigid cell walls
42
Why do fungi have the ability to resist penicillin?
penicillin is a fungus itself
43
Fungi can exist as _____, _____, or both
yeasts or mold
44
Yeasts are ____cellular
unicellular
45
Molds are _____cellular
multi
46
How do yeasts reproduce?
by simple division or budding
47
How do molds reproduce?
they have branching hyphae and form a mycelium (ie. ringworm)
48
Mycoses are diseases caused by ______
fungi
49
What are dermatophytes?
fungi that invade skin, hair, or nails
50
What are the diseases dermatophytes produce called?
"tineas" ie. tinea capitis (scalp)
51
Fungal infections adapt to the host environment by having wide t________ variations and requiring low levels of o______-
temperature; oxygen
52
A low count of what blood cell promotes fungal infections?
white-blood-cells
53
Which fungus is the most common cause of fungal infections?
Candida albicans, especially in cancer and transplant patients
54
Candida albicans is housed as normal microbiota in...
skin, GI tract, and the vagina
55
How might immunocompromised people be affected by Candida albicans?
it can result in a deep infection with high mortality rates
56
What is the death rate of disseminated (spread) cadidiasis?
30-40%
57
Parasites are ___cellular protozoa
unicellular
58
What are helminths?
large worms such as flukes, nematodes, tapeworms
59
How are parasites spread to humans?
vectors or ingestion of contaminated food or water
60
How do parasites damage tissue?
by toxins or the inflammatory/immune response
61
What is the virus that causes Malaria called?
plasmodium vivax
62
Where does the malaria infection occur?
red blood cells
63
Malaria results in anemia within __-__ hours
48-72 hours
64
What causes the symptoms of malaria (fever, chills, vomiting)?
cytokine release (TNF-a and IL-1)
65
What are antibiotics?
natural products of fungi or bacteria that affect the growth of specific microorganisms
66
Antimicrobials can be b_______ or b______
bactericidal or bacteriostatic
67
Bactericidal
agent that kills other microorganisms
68
Bacteriostatic
agent that inhibits growth of other microorganisms
69
What two factors are causing a rise in antibiotic resistance?
-lack of compliance with regimen
-overuse
70
Lack of compliance means...
not using the antibiotic for the prescribed duration
71
What does lack of compliance result in?
the strongest microbes are left alive to repopulate with resistance to the antibiotic
72
What does overuse of antibiotics lead to?
destruction of the normal microbiome to open space for more infectious and resistant pathogens
73
What are vaccines?
biological preparation of weakened or inactivated pathogens
74
How long does it take the adaptive immune system to respond to a pathogen?
2 weeks
75
What does a vaccine do?
activates an adaptive response (2 weeks) against a non-viral pathogen
76
What is the result of a vaccine?
when viral infection occurs, there is no 2 week delay because adaptive immunity is already prepared
77
Can vaccines be mixtures of different pathogens?
yes ie. DTaP or MMR
78
Herd immunity requires what % of the population to be immunized?
85%
79
What is a toxoid?
a chemically altered pathogen toxin injected to allow the body to learn to defeat it (ie. Tetanus toxoid)
80
Passive immunotherapy involves giving p_______ antibodies to a person
preformed
81
Passive immunotherapy is becoming more the focus with the rise in antibiotic _______
resistance
82
What is human immunoglobulin?
antibodies obtained from a pathogen survivor
83
What causes primary (congenital) immunodeficiency?
genetic defect
84
What causes secondary (acquired) immunodeficiency?
another illness (ie. cancer)
85
Most primary immune deficiencies result from how many gene defects?
one
86
Are primary immune deficiency mutations sporadic or inherited?
sporadic, the mutation occurs before birth
87
Sporadic Gene Mutation
mutation that is not inherited by parents but can be passed on to the children of the person who acquired the disease via mutation
88
When do the symptoms of a primary deficiency appear?
early OR late in life
89
1 in ___ Canadians have a primary immune deficiency but __% of these cases are undiagnosed.
1 in 200; 70%
90
How are primary immune deficiencies categorized?
based on what aspect of the immune system is defective (ie. B and T lymphocyte or antibody deficient)
91
Combined Immune Deficiency
group of rare genetic disorders of the immune system (ie. SCID, DiGeorge, Hypogammaglobulinemia)
92
Severe Combined Immunodeficiency (SCID) results from an underdeveloped ________
thymus
93
What does the thymus do?
produces T cells
94
What results from SCID?
absence of T cells (lymphocytes)
95
DiGeorge syndrome results from a dysfunction of the ________ and ________ gland
thymus and parathyroid gland
96
What is the result of DiGeorge syndrome?
-inadequate T cell production (thymus)
-plasma calcium management impaired (pt gland)
97
Hypogammaglobulinemia results from a defect in __ cell maturation or function
B cells
98
What is the result of Hypogammaglobulinemia?
low levels of circulating antibodies (immunoglobulins) in the blood
99
Are primary or secondary immune deficiencies more common?
secondary
100
Why are secondary immune deficiencies not as clinically relevant?
the degree of immune deficiency is usually minor
101
What are some extreme secondary deficiencies?
AIDS or cancer
102
How do you evaluate immunity?
complete blood count (CBC) with differential
103
What is a complete blood count (CBC)?
the total number of RBC, WBC, and platelets in the blood
104
What is 'differential'?
the individual numbers of lymphocytes, monocytes, granulocytes
105
Immunity Evaluation: Quantitative determination of ___________ of immunoglobulins
subpopulations
106
What does 'total complement assay' measure?
the total number of complements (MAC) in blood
107
Replacement Therapies for Immune Deficiencies: Stem Cell Transplant
taking stem cells from bone marrow or umbilical cord cells to improve immunity
108
Stem cell transplant results are usually __(temporary/permanent)__
temporary
109
Replacement Therapies for Immune Deficiencies: Mesenchymal Stem Cell (MSCs) Injection
uses undifferentiated stem cells in bone marrow that eventually undergo differentiation
110
MSCs injections have strong immunosuppressive properties meaning...
they can stop a variety of immune functions as well
111
Replacement Therapies for Immune Deficiencies: Gene Therapy
insertion of normal genes into defective genetic material which reconstitutes the immune system
112
What do some gene therapy recipients develop?
leukemia
113
What viral disease causes Acquired Immune Deficiency Syndrome (AIDS)?
Human Immunodeficiency Virus (HIV)
114
What does HIV do?
depletes helper T cells necessary for T and B cell activation
115
What is the result of HIV?
dysfunctional adaptive immune system that increases susceptibility to disease, AIDS
116
____sexual activity is the most common transmission route for AIDS
heterosexual (M/f)
117
Are more women or men infected by AIDS?
more than 50% are women
118
How do children contract HIV from their mothers?
across placenta or by breastmilk
119
Why has a HIV vaccine not been developed?
HIV has variable antigen and genetic properties
120
What is the issue with the antibodies of people with HIV?
they have lots but they aren't protective, meaning even vaccine antibodies may not function effectively
121
Epidemiology
branch of medicine that deals with incidence, distribution, and control of disease
122
What is anti-retroviral therapy (ART) and what is it used for?
a drug containing RNA rather than DNA (retroviral) used to treat HIV
123
What does ART do?
uses a combination of entrance, reverse transcriptase, integrase, and protease inhibitors to stop HIV from reproducing in cells
124
Is ART curative of HIV?
no, but it decreases mortality rate
125
Hypersensitivity is an...
altered immunological response to an antigen that results in disease or damage to the host
126
3 Types of Hypersensitivity
1. allergy
2. autoimmunity
3. alloimmunity
127
Allergy
effects of hypersensitivity to environmental antigens (ie. pollen, bee sting)
128
Exogenous Antigens
environmental antigens found outside human cells
129
Endogenous Antigens
antigens found within human cells
130
What is autoimmunity?
a disturbance in immunological tolerance of self-antigens (immune system doesn't recognize its own antigens)
131
What are autoimmune diseases?
clinical disorders of autoimmunity
132
What is alloimmunity?
an immune reaction to the tissue of another individual
133
When do alloimmune reactions occur?
blood transfusions, transplants, pregnancy
134
How are hypersensitivity reactions characterized?
by their immune mechanism (Type I, II, III, IV)
135
What do we mean when saying "hypersensitivity mechanisms are interrelated"?
hypersensitive reactions usually include more than one type of immune mechanism
136
Immediate Hypersensitivity Reaction
reaction occurs within minutes or hours (ie. Anaphylaxis)
137
Anaphylaxis
the most rapid and severe immediate reaction that occurs within minutes
138
Anaphylaxis symptoms
-pruritis: severe itching
-erythema: red patches on skin
-vomiting
-diarrhea
-difficulty breathing
139
Delayed Hypersensitivity Reaction
reaction occurs after several hours, are at maximal several days later
140
Type I Hypersensitivity = ___ mediated
IgE (+ products of mast cells - histamine)
141
What is the most common hypersensitivity reaction?
Type I
142
Type I occurs against ________ antigens, inducing an allergic reaction
environmental
143
Step 1: Type I Reaction - Initial Exposure to Allergen
sensitization: IgE binds to mast cell receptors
144
Step 2: Type I Reaction - Subsequent Exposure to Allergen
hypersensitive reaction: mast cells release cytokines (histamine)
145
During a Type I reaction which tissues are most commonly affected? Why?
skin, GI tract, and pulmonary tract tissues that have lots of mast cells
146
Atopic
individuals predisposed to developing allergies when they have parents with allergies
147
If one parent has allergies, ___% of offspring will
40%
148
If both parents have allergies, ____% of offspring will
80%
149
Example of Type I hypersensitivity
Hay fever
150
Type II (cytotoxic) Hypersensitivity = ______ specific
tissue
151
What does Type II do?
antibody mediated destruction of healthy host cells
152
Type II is a reaction against a _______ cell or tissue
specific
153
Tissue-Specific Antigens
attach only on the plasma membranes of certain cells (ie. platelets)
154
How many mechanisms of Type II exist?
5 - A, B, C, D, E
155
Step 1 of Type II Reaction (for all 5 subtypes)
antibody bind to tissue-specific antigens
156
Type II Mechanism A (hint: compliment)
cell is destroyed by antibodies and compliments (MAC ruptures cell wall)
157
Type II Mechanism B (hint: eating)
cell is destroyed by phagocytosis via macrophage
158
Type II Mechanism C (hint: neutrophil)
neutrophils produce toxic products (granules) that damage tissue
159
Type II Mechanism D (hint: ADCC)
Antibody-Dependent Cell-mediated Cytotoxicity (ADCC) - IgG antibodies bind to antigens and attract NK cells to destroy cell
160
Type II Mechanism E (hint: block)
mechanism doesn't destroy the target cell but causes it to malfunction because the antibody binding blocks normal receptor functions
161
Grave's Disease is an example of Type II mechanism __
E
162
Type II example
hemolysis in medication allergies
163
Type III Hypersensitivity = _______ complex
immune
164
What is formed in circulation during a type III reaction?
antigen-antibody immune complex
165
Where is the antigen-antibody immune complex deposited in a type III rxn?
in vessel walls or extravascular tissue
166
Gluten allergies are an example of a Type ___ reaction
III
167
Type IV Hypersensitivity = ___ mediated
cell, specifically T cells (not ANTIBODIES)
168
Mechanism of a Type IV reaction:
reaction activated T cells which activate macrophages to destroy tissues
169
Type IV reaction examples
graft rejection, poison ivy, metals
