Immunity And Classification Flashcards
1
Q
The 5 general characteristics to classify bacteria (and example of each)
A
- Macroscopic (colony morphology/ growth characteristics)
- Biochemical traits (production of certain end products/ use certain substrates/ selective media)
- Growth Requirements (anaerobic vs aerobic etc.)
- Microscopic (cell morphology/ differential strains)
- Specialized tests/ secretion pathways
2
Q
Seven characteristics associated with colony morphology
A
“PEETOSS” Pigmentation Edge/margin Elevation Texture Optical Properties Size Shape
3
Q
Three biochemical/ metabolic traits
A
- Utilization of specific substrates as a nutrient (lactose or citrate as energy source)
- Growth on differential/ selective media (hydrolytic patterns on blood agar)
- Production of certain end products (fermentation producing alcohol or acid)
4
Q
Fastidious growth requirements
A
Picky eater- numerous nutrient requirements
5
Q
Nonfastidious growth requirements
A
Will grow on anything
6
Q
Microaerophile oxygen requirements
A
Utilizes some O2 but can’t be exposed to too much or will die
7
Q
Aerotolerant oxygen requirement
A
Can live in O2 but doesn’t need it
8
Q
Facultative oxygen requirement
A
Can live without oxygen but would grow better with it
9
Q
Gram stain enables classification based on what?
A
Cell wall structure
10
Q
Bacilli
A
Rod-shaped
11
Q
Cocci
A
Spherical shaped
12
Q
Spirilla
A
Spiral shaped
13
Q
Vibrio
A
Curved
14
Q
Spirochete
A
Thin spring, flexible and tightly coiled
15
Q
Palisade
A
Bacilli lined up along each other like sardines
16
Q
Coccobacilli
A
Rounded oval rectangular-ish shape
17
Q
Diplo-bacilli
A
Two rods in a chain
18
Q
Strepto
A
Three or more in a chain
19
Q
Staphylo
A
Clusters
20
Q
Molecular characteristics used for bacterial classification
A
OCR, Nucleic acid sequence analysis, restriction fragment length polymorphism (RFLP), DNA hybridization, Phage-GFP,
21
Q
Type 3 Secretion pathway
A
Found in gram negative bacterial only, secretes proteins from cytoplasm into host cell. Contact dependent (injects toxin into host cell directly).
Secretion machinery is needle shaped and secreted proteins are thought to move through a translocation channel
22
Q
Type 4 secretion pathway
A
Found in gram negative and gram positive, similar to conjugation system (secrets protein and transfers DNA during conjugation) can go bacteria to bacteria or bacteria to eukaryote. ATP dependent
23
Q
Shortages bacterial secretion pathway
A
Found in gram positive bacteria, covalently attach proteins to cell wall following secretion, assist in survival during infection (attachment is first and most important part of infection)
24
Q
Injectosome bacterial secretion pathway
A
Found in gram positive bacteria, similar to type 3 and 4 systems of gram negatives
25
Definition of immunity
The ability to ward off disease through body defenses
26
Characteristics of Innate immunity
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Nonspecific resistance
Routine protection
Defenses against any pathogen
Immediate response with no memory
Refers to whatever defenses are present at the time
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27
Characteristics of adaptive immunity
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Pathogen-specific resistance
Acquired during the lifetime
Requires time to develop (2 exposures)
Involves specialized cells
Has memory
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28
Characteristics of the first line of defense
Nonspecific natural barriers that restrict entry or means for physical removal of a pathogen (skin, mucous membranes and their secretions, normal micro flora)
29
Characteristics of the second line of defense
Nonspecific immune defenses that provide rapid local response to pathogen after it has entered the host (natural killer cells and phagocytic white blood cells- macrophages and neutrophils-, inflammation, fever, antimicrobial substances)
30
Skin chemicals in first line of defense, and their role
In perspiration: salt (hypertonic environment, antimicrobial peptides, lysozyme enzymes to destroy bacterial cell wall)
In sebum: keeps skin pliable and less likely to tear, lowers skin pH to a level damaging to most bacteria)
31
Three layers of mucous membranes and their uses
1. Epithelium (thin, tightly packed outer covering, shedding to carry away microorganisms)
2. Dendritic cells below epithelium to phagocytize pathogens and goblet/ ciliated columnar cells to remove invaders
3. Deeper connective layer to support the epithelium- produces required chemicals
32
Lacrimal apparatus
(Tear production) continual washing and blinking to prevent microbes from settling on eye surface, plus lysozyme in tears to break down any particulate matter
33
Ciliary escalator
Cilia on mucous membranes of lower respiratory tract move upwards towards through at 1-3cm/ hour- raised up high enough so you can cough/ sneeze it up
34
Chemical defenses of mucus
Glycoproteins and water, thick, inhibits colonization by preventing critical mass
35
Chemical defenses of gastric juices
Acidic (pH 1-3 destroys most bacteria) contains enzymes and mucus
36
Chemical defenses of lysozyme
Enzyme in most body secretions that degrades peptidoglycan
37
Chemical defenses of transferrins
Iron binding proteins in blood which inhibit bacterial growth by reducing available iron (bacteria have a huge need for iron)
38
Microbial antagonism
Normal micro flora compete for resources with potential pathogens. May even produce antibiotic compounds toxic to non-native species
39
Eosinophils
Fight parasitic worms and are involved in allergic reactions. A type of granulocyte with cytoplasmic granules
40
Basophils
Involved in allergic reactions and inflammation (similar to mast cells, found in tissues) a type of granulocytes (cytoplasmic granules) release histamine and other inflammation causing chemicals from the granules
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Neutrophils (PMN’s)
Account for most of the leukocytes, usually not seen in tissues except during inflammation. Phagocytize and digest engulfed materials
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Lymphocyte (B and T cells)
Single nucleus (mostly nucleus with not much cytoplasm before differentiation) seen in lymph nodes/ spleen and tonsils and in circulation, participate in adaptive immune response
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Monocytes
Single nucleus, lots of cytoplasm. Differentiate either into macrophages or dendritic cells. Will phagocytize and digest engulfed materials
44
Macrophages
Present in virtually all tissues. Given names based on what tissue they’re found in.
1. Alveolar= lung
2. Kupffer= liver
3. Microglial= brain
4. Histocyte= tissue
5. Langerhans= skin/mucosa
45
Dendritic cells
Branched, in tissues but eventually migrate to lymph infection nodes/ organs. Gather antigen from tissues and present it to lymphocytes that congregate in secondary lymphoid organs, developing an adaptive response
46
Steps of phagocytosis
1. Chemotaxis
2. Recognition and attachment
3. Engulfment
4. Phagosome maturation/ phagolysosome formation
5. Destruction and digestion
6. Formation of residual body
7. Exocytosis
47
Chemotaxis (phagocytosis)
Phagocytes recruited by chemoattractants produced by phospholipids form injured host cells, chemokines and C5a
48
Recognition and attachment (phagocytosis)
Direct (Pattern recognition receptors to PAMP or DAMP) or indirect (binding to opsonins)
49
PRR
Pattern recognition receptors on macrophages that detect pathogen-associated molecular patterns (PAMP), or danger-associated molecular patterns (DAMPs) aka host cell damage
50
Three types of PRR’s
1. Toll-like receptors (internal or external antigen receptors) anchored in membranes
2. NOD-like receptors, found internally only- in cytoplasm. Detect bacterial components indicating the cell has been breached.
3. RIG-like receptors. Also found internally only- in the cytoplasm. Detect viral RNA, indicating infection. Will produce interferons
51
Engulfment (phagocytosis)
Pseudopods surround and a phagosome is formed
52
Phagosome maturation and phagolysosome formation (phagocytosis)
Endoscopes fuse, lower pH, lysosome brings digestive enzymes
53
Destruction and digestion (phagocytosis)
Toxic ROS and nitric oxide produced, pH decreases, enzymes degrade, defensins damage membrane of invader, lactoferrin ties up iron
54
Formation of the residual body (phagocytosis)
Indigestible material remaining in the phagolysosome
55
The complement system
Helps the ability of antibodies and phagocytic cells to clear pathogens from an organism. Part of innate immune system, but can be brought online by adaptive immune response. Act as a cascade
56
Opsonization (complement activation)
C3b complement protein binds to bacterial cells and foreign particles, allows phagocytic cells to engulf more easily
57
Consequences of complement activation
1. Opsonization (C3b binds to pathogens, engulfed more easily)
2. Inflammatory response (C5a attracts phagocytes and C3a partners to increase blood vessels to become more permeable and for mast cells to release cytokines)
3. Lysis fo foreign cells (membrane attack complexes are formed out of many complement proteins to insert into the pathogen’s cell membrane and cause all the contents to leak ou)
58
Inflammation definition and signs
Nonspecific response to tissue damage from various causes
| Characterized by redness, heat, swelling and pain
59
Role of Histamine in inflammation
Vasodilation, increased permeability of blood vessels
60
Role of kinins in inflammation
Vasodilation, increased permeability of blood vessels
61
Role of prostaglandins in inflammation
Regulates intensity of histamine and kinin effects
62
Role of leukotrienes in inflammation
Increased permeability of blood vessels, phagocytic attachment
63
Acellular entities that can cause disease in human hosts is/are
A. Bacteria B. Fungi, C. Viruses D. All of the above
C. Viruses
64
A biochemical characteristic that could be used to classify a microbe is A. An end or by-product of sugar fermentation B. Production and secretion of toxins C. Both A and B, D. Neither A nor B
C. Both A and B
65
The gram stain enable bacteria to be classified based on
| A. Macroscopic characteristics B. Staining pattern of the cell wall C. both A and B D. neither A nor B
B. Staining pattern of the cell wall
66
Size, margin, texture, and pigmentation are terms used to describe
A. Cell morphology B. Colony morphology C. Antimicrobial susceptibility D. A pathogen’s molecular characteristics
B. Colony morphology
67
Which of the following is true?
A. The normal flora never cause disease in a human host
B. The normal flora provides protection against bacterial diseases only
C. the normal flora can protect the host from pathogenic microbes by creating an inhospitable environment
D. Normal flora consists of bacteria only
C. the normal flora can protect the host from pathogenic microbes by creating an inhospitable environment
68
The three characteristics of size, shape, and arrangements are usually used to classify...
Bacteria
69
Which of the following would be used in microbial classification
A. hemolytic patterns of blood agar
B. Production of an enzyme such as catalase
C. Both a and b
D. Neither a nor b
C. Both A and B
70
The patient is considered to be in the disease state when
A. microbial colonization has occurred
B. Microbial growth is rapidly occurring
C. Tissue damage or dysfunction has occurred due to the microbe
D. A microbe has attached
C. Tissue damage or dysfunction has occurred due to the microbe
71
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Classifying bacteria using oxygen utilization is an example of
A. Morphological characteristics
B. Biochemical characteristics
C. Molecular methods
D. All of the above
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B. Biochemical characteristics
72
Which of the following contributes to protecting the eyes from microbial invasion?
A. Tears contain lysozyme
B. Tears mechanically flush particles from the eyes
C. Both A and B
D. Neither A nor B
C. Both A and B
73
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The process of phagocytosis involve all of the following except
A. Adhesion
B. Chemotaxis
C. Secretion of cytotoxins
D. Vesicles fusion
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C. Secretion of cytotoxins
74
First line of defense may be described as
A. Damage resulting in cell lysis
B. The coating of a pathogen by complement
C. Nonspecific leukocytes that secrete toxins onto the surface of virally infected cells
D. Intact skin, mucous membranes, sebum, tears and so forth
D. Intact skin, mucous membranes, sebum, tears and so forth
75
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Which cell becomes a macrophage when leaving the blood stream?
A. Neutrophil
B. Basophils
C. Eosinophil
D. Monocytes
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D. Monocytes
76
The Simmons citrate test allows the user to determine in an organism has the ability to use citrate as its sole carbon source. This test is an example of ________________ Characteristics used for bacterial classification
Biochemical
77
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Which of the following is a component of the innate immune response?
A. Phagocytosis
B. Inflammation
C. Complement
D. All of the above
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D. All of the above
78
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The skin and mucous membranes are primarily examples of
A. Chemical barriers
B. Physical barriers
C. Enzymatic barriers
D. None of the above
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B. Physical barriers
79
Descriptive such as margin, shape, pigmentation and texture are used for...
Colony morphology
80
B cells and neutrophils both arise in the ....
Bone marrow
81
Cocci shaped bacteria growing in a cluster have a ___________ arrangement
Staphylo
82
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Which of the following are examples of polymorphonuclear cells?
A. Macrophages
B. B cells
C. Neutrophils
D. Two of the above
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C. Neutrophils
83
The recognition of pathogens by phagocytic cells is accomplished by interactions between ____________ on pathogens and ____________ on the phagocytic cells
PAMP’s; PRR’s
84
How do fevers help and why do they start?
Fevers affect the growth rate of mesophilic microbes (slows) giving the immune system more time to act.
Fevers result when pyrogens trigger the hypothalamus to increase the body’s core temperature
85
What are pyrogens? Give examples
Substance that cause a fever
- bacterial toxins
Cytoplasmic contents of bacterial released by lysis
Antibody-antigen complexes
Pyrogens released by phagocytes that have phagocytize bacteria (cytokines released by TLR’s- activated macrophages)
86
5 attributes of adaptive immunity
1. Specificity
2. Inducibility
3. Clonality (proliferation)
4. Unresponsiveness to self (tolerance)
5. Memory
87
Maturation of B- lymphocytes
Occurs in the bone marrow
88
Maturation of T-lymphocytes
Occurs in the thymus
89
Two types of adaptive immune response
Cell-mediated (CMI) and Humoral immune response
90
Cell-mediated immune response definition
T-cell mediated, elimination of intracellularly located antigens and cancerous or abnormal cells
91
Humoral immune response definition
B-cell mediated (antibody mediated) antibodies function to eliminate extra cellular antigens such as bacteria, toxins, and viruses in bloodstream, tissues and fluids
92
Primary lymphoid organs
Where lymphocytes form
| Red bone marrow (B and T, B mature) and Thymus (T mature)
93
Lymph components
Liquid with similar composition to blood plasma, that leaks from blood vessels into surrounding tissues, and contains white blood cells and antigens from tissues
94
Lymphatic vessels
One-way system that conducts lymph from tissues and returns it to the circulatory system
95
Antigen
Describes a molecule that reacts specifically with antibody, a B cell receptor or a T cell receptor ( if elicits an immune response= immunogenicity). Proteins typically elicit strong responses
96
Epitomes (antigenic determinants)
Antigen’s recognizable 3-dimensional regions
97
Hapten
Small molecule which are non-antigenic unless attached to larger carrier molecules
98
Superantigen
Antigen which can cause a non-specific immune response
99
Exogenous antigens
Include toxins and other components of microbial cell walls, membranes, flagella and pilli
100
Endogenous antigens
Produced by microbes that reproduce inside a body’s cell once infected
101
Autoantigens
Derived from normal cellular processes and denote a healthy functioning normal body cell
102
MHC class !
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Present on all nucleated cells (except blood cells) present endogenous antigens when infected with intracellular pathogens
— Cells with internal pathogens down regulated the presentation of class I, so will signal killer T-cells to destroy
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103
MHC class II
For extracellular non-self entities— present on antigen-presenting cells such as macrophages, dendridic cells and B-cells (present the antigens of pathogens it’s phagocytize already)
104
T-lymphocytes
Circulate in lymph and blood— T-cell receptor can only bind to PROTEINaceous epitomes associated with an MHC protein
105
Three types of T-lymphocytes
1. Cytotoxic T-lymphocytes (CD8+)
2. Helper T-lymphocytes (CD4+)
3. Regulatory T-lymphocyte
106
Cytotoxic T-lymphocyte
CD8+
Directly kills other cells
Secretes performing and granzyme
107
Helper T-lymphocytes
CD4+
Lynchpin of adaptive immunity
Helps regulate B-cells and cytotoxic T- cells
Includes type 1 and type 2 helper T-cells
Secretes interleukins 2 and 4, and IFN-y
108
Regulatory T-lymphocyte
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Repressive adaptive immune responses as negative feedback (disfunction in chronic inflammation)
Secretes cytokines (interleukin 10)
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109
6 functions of antibodies
1. Activation of complement and inflammation- activate complement system which results in cell lysis and inflammation
2. Neutralization
110
5 antibody isotopes
IgM, IgG, IgA, IgE, IgD
111
IgM
Always first isotope produced in an immune response
| Exists in membrane-bound form (monomer) and blood-stream bound pentamer used for agglutination
112
IgG
Exists as a monomer, most prevalent and provides long-term protection through all antibody functions. Maternal IgG protects fetus by transporting across fetus and gradually subsiding as baby’s immune system kicks in
113
IgA
Can exist as a monomer or a dimer
Secreted form (dimer) important in mucosal immunity, as well as protecting breast-fed infants against intestinal pathogens 🦠
Works mostly through neutralizing toxins and interfering with attachment to host cell
Produced by mucosa-associated lymphoid tissue (MALT)
114
IgE
Usually really low concentration, and exists as a monomer. Found bound to mast cells and basophils as well as in blood. Usually seen in larger quantities when there is an active parasitic infection or allergy
115
IgD
Membrane bound form serves as b-cell receptor, and free in blood. Function not known
116
5 types of immune-response cytokines
1. Interleukins: signal among leukocytes
2. Interferons: antiviral proteins that may act as cytokines
3. Growth factors: proteins that stimulate stem cells to divide
4. Tumor necrosis factor: secreted by macrophages and t-cells to kill tumor cells and regulate immune responses and inflammation
5. Chemokines: chemotactic cytokines that signal leukocytes to move
117
Two types of cell-mediated immune responses
1. Perforin-granzyme pathway
| 2. FAS or CD95 pathway
118
Performing-granzyme pathway
Cytotoxic t-cell binds to class 1 MHC/ antigen complex on target cell and releases the enzyme complex perforin (Formosa pore) through which secreted granzyme to enter the cell and trigger apoptosis
119
FAS or CD95 pathway
Cytotoxic t-cell binds to class 1 MHC/ antigen complex on target cell, and interaction of the ligand on T-cells and receptor on abnormal cells lead to the release of caspase enzymes,which trigger apoptosis
120
Two other outcomes of Cell-mediated immune response
1. Enhancement of macrophage killing ability (^ size, metabolism # of lysosomes, and form giant cells)
2. Memory T-cells (immediately functional upon subsequent contacts with epitope-MHC complex specific to its TCR)
121
Natural Killer Cells
Non-phagocytic granular lymphocytes- bind to Antibodies which coat microbe (antibody-dependent cell-mediated cytotoxicity) and lyse cell- no specificity. OR recognize that infected cell lack MHC 1, and kill using perforin and granzyme
122
Two types of humoral responses
Both antibody immune responses mounted against exogenous pathogens and toxins (only in response to specific pathogens)
1. T-dependent, requires helper T-cells (proteins)
2. T independent- can be bound directly to B cells, but only IgM made
123
T-Dependent antigen humoral response
1. B-cell receptor binds to antigen, internalized and processed
2. Antigen presentation occurs
3. TCR on helper T-cell bind on B-cell surface, cytokines secreted, B-cell activated
4. Differentiate into plasma cells (short-lived, produced antibodies) and memory cells (longer-lived, initiates antibody production if antigen is encountered again)
124
T-independent antigens humoral response
T-independent antigens can activate B cells without T-helper cells, and epitomes are bound by clusters of B-cell receptors (usually evenly spaced)
Usually results in production of majority IgM antibodies
125
4 Types of acquired immunity and examples
1. Passive naturally acquired: antibodies pass from mother to fetus via placenta or breast milk
2. Active naturally acquired: antigens/ pathogens exposed to daily/ naturally. Body generates response (mono)
3. passive artificially acquired: preformed antibodies introduced into body (snake anti-venom) body doesn’t make more of these
4. Active artificially acquired: antigens introduced in vaccines (immunization) and body generates an immune response to these antigens
126
Attenuated vaccines
Uses pathogens reduced in virulence to confer life-long immunity. Can result in mild infections in susceptible individuals
127
Inactivated vaccines
Uses inactivated (killed) but whole microbes. Doesn’t produce life-long immunity: requires boosters
128
Subunit vaccines
Antigenic fragments of microbes: often require multiple doses to achieve full immunity, and often contains adjuvants (chemicals added to increase effective antigenicity)
129
Toxoid vaccines
Chemically/ thermally modified toxins used to stimulate active immunity (antibody mediated only) requires boosters
130
Type 1 hypersensitivity
ANAPHYLACTIC Antigen causes an immediate anaphylactic allergic reaction— either systemic (total system impairment) or localized (hay fever, asthma, hives)
131
Type 2 hypersensitivity
CYTOTOXIC When cells are destroyed by an immune response: component of most autoimmune diseases. (Like when blood cells with the incorrect antibodies are attacked, from incompatible blood transfusion or fetal red blood cells)
132
Example of Type 2 (Cytotoxic Hypersensitivity)
Rh Antigen incompatibility: 85% of humans are Rh Positive, so if Rh- woman is carrying a Rh+ fetus, antibody immune response may be initiated against the fetal cells, causing risky pregnancy and hemolytic diseases
133
Type 3 Hypersensitivity
[Immune complex mediated] immune complexes accumulated and become trapped in tissues, and inflammation causes tissue damage. May be localized or systemic: examples are arthritis and lupus
134
Type 4 Hypersensitivity
[Delayed or cell mediated] Inflammation 12-24 hours after contact with certain antigens- reflects the time it takes for macrophages/ T-cells to migrate to and proliferate at the site of the antigen (contact dermatitis)
135
Primary immunodeficiency diseases
Result from some genetic or developmental defect (develop in infants and young children)
Lack of B-cell and/or T-cell activity (may lack antibodies, may lack a normal thymus, or more severely may be missing both)
136
Acquired immunodeficiency diseases
Develop as direct consequence of some other recognized cause later in life. May be caused from SEVERE stress (excess production of corticosteroids), malnutrition/ environmental factors that inhibit the production of B/T cells, or AIDS
