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Microbiology Final
Crowder College Microbiology Final Chap. 16, 17, 18
116
Microbiology
Undergraduate 3
12/11/2011

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Term
Vaccine
Definition
A suspension of microorganisms or fractions of microorganisms that is used to induce immunity
Term
Why do anitigens in vaccines not cause disease?
Definition
They are either killed, weakened or non-living
Term
What are the four main types of vaccines?
What are two other types of vaccines?
Definition
1) Attenuated whole-agent
2) Inactivated whole-agent
3) Subunit
4) Toxoids
Other: 1) Conjugated 2) Nucleic acid
Term
Describe an attenuated whole-agent vaccine?
Definition
Uses living, but weakened microbes--weakened by serial passage through a "poor" host for the virus
Term
What are three examples of an attenuated whole-agent vaccine?
Definition
1) MMR-measles, mump and rubella
2) Oral Polio virus vaccine
3) Tuberculosis vaccine
Term
What are four advantages of an attenuated whole-agent vaccines?
Definition
1) Microbes multiply in the body
2) The original dose is increased with time, acting as a series of secondary immunizations
3) Generally provides strong and long lasting immunity
4) Immunizes contacts, good for the entire population
Term
What are two disadvantages of an attenuated whole-agent vaccines?
Definition
1) Not recommended for immunosuppressed people
2) Microbes can back mutate to a more virulent form
Term
Describe inactivated whole-agent vaccine.
Definition
Uses microbes that are "killed" by chemical (usually with formalin or phenol) or physical treatment
Term
Give three examples of inactivated whole-agent vaccine.
Definition
1) Influenza
2) Inactivated Polio virus vaccine
3) Rabies
Term
What are two advantages of inactivated whole-agent vaccines?
Definition
1) Not disease-causing because microbes are non-living
2) Cannot harm immunosuppressed people
Term
What are three disadvantages of inactivated whole-agent vaccines?
Definition
1) Antigen dose doesn't increase in the host since microbes cannot multiply
2) Short-lived immunity, immunity is not as strong as with attenuated whole-agent vaccines
3) Doesn't immunize contacts, not good for the entire population
Term
Describe a subunit vaccine.
Definition
Contain only part of a microorganism that best stimulate an immune response, such as a bacterial cell wall, capsule components, viral coat or envelope
Term
What are the two basic types of subunit vaccines?
Definition
1) Capsular: use bacterial capsular proteins
2) Recombinant: use viral proteins that are made by genetic engineering
Term
What is an advantage of subunit vaccines?
Definition
Not disease-causing, microbes are non-living
Term
What is a disadvantage of subunit vaccines?
Definition
Weaker immune response
Term
What are two examples of a subunit vaccine?
Definition
1) Hepatitis B
2) Pneumococcal pneumonia
Term
Describe a toxoid vaccine.
Definition
A bacterial toxin that is inactivated with chemicals without altering its antigenic properties.
Produces antibodies that can bind to the toxoid and that actual toxin.
The neutralizes the toxin by stopping attachment to the host cells.
Term
What are two examples of toxoid vaccines?
Definition
1) Tetanus toxoid
2) Diphtheria toxoid
Term
What are three advantages of toxoid vaccines?
Definition
1) Stimulate strong antibody production
2) Produce long-lasting memory cells
3) Toxoid cannot cause any disease
Term
What are two disadvantages of toxoid vaccines?
Definition
1) Require series of injections
2) Require boosters every 10 years
Term
What are four characteristics of conjugated vaccines?
Definition
1) This has been developed to deal with poor immune response of children to vaccines based on capsular polysaccharides.
2) Polysaccharides are T-independent antigens.
3) Children's immune system do not respond to these antigens until the age 15-24 months
4) Polysaccharides are combined with proteins such as diphtheria toxoid
Term
What is an example of a conjugated vaccine?
Definition
Hib vaccine: capsular polysaccharides and diphtheria toxoid together to enhance immune response; provides significant protection even at 2 months of age
Term
What are three characteristics of nucleic acid vaccines?
Definition
1) DNA vaccines are among the newest and most promising vaccines
2) There aren't any commercial DNA vaccines for humans
3) DNA remain efficient only until it is degraded
Term
Innate immunity
Definition
Defenses against any pathogen
Immunity you are born with
Term
Immunity
Definition
Specific antibody and lymphocyte response to an antigen
Term
Antigen (Ag)
Definition
A substance that causes the body to produce specific antibodies or sensitized T cells
Term
Antibody (Ab)
Definition
Proteins made in response to an antigen
Term
Serology
Definition
Study of reactions between antibodies and antigens
Term
Antiserum
Definition
Generic term for serum because it contains antibodies
Term
Globulins
Definition
serum proteins
Term
Gamma globulin
Definition
Serum fraction containing Ab
Term
Acquired immunity
Definition
Developed during an individual's lifetime
Term
Humoral immunity
Definition
Antibody-mediated immunity
Involves Ab produced by B cells
Term
Cell-mediated immunity
Definition
Involves T cells
Term
Immunity resulting from infection; when a person gets sick
Definition
Naturally acquired active immunity
Term
Immunity acquired transplacental or via colustrum (when a fetus or infant gets immunity from mother)
Definition
Naturally acquired passive immunity
Term
Immunity acquired from the injection of Ag (vaccination or immunization)
Definition
Artificially acquired active immunity
Term
Immunity acquired from the injection of Ab or serum globulins
Definition
Artificially acquired passive immunity
Term
Haptens
Definition
1) Hapten molecule and carrier molecule together make the complete antigen
2) Hapten molecules are too small to stimulate antibody formation, but with carrier molecules they form larger antigens that can stimulate antibody response
Term
Five characteristics of antibodies.
Definition
1) Antibodies have a "Y" shape
2) Antibody is made up of heavy chains and light chains
3) Di-sulfide bonds link different regions together
4) An antibody has a constant region (c) and a variable region (v)
5) Antigens attach to the variable region of the antibody molecule
Term
What are the five classes of immunoglobulins (antibodies)?
Definition
1) IgG
2) IgM
3) IgA
4) IgD
5) IgE
Term
Which antibody is the most abundant in serum?
Definition
IgG
Term
What antibody is the most abundant in our body?
Definition
IgA
Term
Which antibody is the least abundant in the body?
Definition
IgE
Term
Which antibodies are monomers?
Definition
IgG, IgD, IgE
Term
Which antibodies are dimers?
Definition
IgA
Term
What antibodies are pentamers?
Definition
IgM
Term
Which antibody is found in mucus, saliva and tears?
Definition
IgA
Term
Which antibody is found on B cells?
Definition
IgD
Term
What antibody can fix complement?
Definition
IgG
Term
Which antibody can agglutinate antigens?
Definition
IgM
Term
Presence of which antibody indicates a current infection?
Definition
IgM
Term
Describe B cell clonal selection.
Definition
When a B cell recognizes and binds to the specific antigen; B cell proliferates into a large clone of cells; in other words, B cell makes large number of similar B cells
Term
Differentiation of B cells
Definition
Some B cells differentiate into long-lived memory cells and remain in the body for ever; Some B cells differentiate into plasma cells
Term
Self-tolerance
Definition
Body doesn't make antibodies against it's own self cells. The immune system can differentiate between self and nonself.
Term
Clonal deletion in relation to our immune system
Definition
Process of destroying B and T cells that react to self-antigens
Term
Apoptosis
Definition
Programmed cell death; human body makes about 100 million lymphocytes each day so an equal number must die
Term
What are the six ways Ag-Ab binding helps stop pathogenic bateria from causing disease?
Definition
1) Agglutination
2) Opsonization
3) Neutralization
4) Activation of complement
5) Inflammation
6) Antibody dependent cell-mediated cytotoxicity
Term
Agglutination
Definition
enhance phagocytosis by decreasing the number of infectious units
Term
Opsonization
Definition
Immune adherence: enhance phagocytosis by coating antigen with antibody
Term
Neutralization
Definition
block attachment of bacteria and viruses to the mucosal membranes; block active site of toxins
Term
Activation of complement
Definition
Attract complement to the surface of bacteria, this leads to cell lysis or cytolysis
Term
Inflammation
Definition
disruption of cells by complement attract phagocytes and other immune system cells
Term
Antibody dependent cell-mediated cytotoxicity
Definition
enhance the activity of non-specific immune system cells; NK cells and neutrophils
Term
What are cytokines?
Definition
The chemical messengers of immune cells
Term
What are interleukins?
Definition
Cytokines that act as communicators between leukocytes
Term
What are antigen presenting cells?
Definition
Dendritic cells, abundant in the skin and mucous membranes, that ingest and process the antigen and display fragments of the antigen on the surface
Term
What are the four types of T cells?
Definition
1) Helper T cells
2) Cytotoxic T cells
3) Delayed Hypersensitivity T cells
4) Suppressor T cells
Term
Helper T cells
Definition
Activate cells related to cell-mediated immunity
Activate B cells
Term
Cytotoxic T cells
Definition
Releasing a protein called perforin
Forms a pore in the membrane causing the infected cell to lyse
Term
Delayed Hypersensitivity T cells
Definition
Associated with allergic reaction, transplant rejection, reaction to poison ivy and tuberculin skin test
Term
Suppressor T cells
Definition
Turn off immune response when antigen is no longer present
Term
Describe T-dependent antigens and give an example
Definition
Requires the assistance of helper T cells to produce antibodies; proteins found on viruses and bacteria
Term
Describe T-independent antigens and give an example
Definition
Antigens that stimulate the B cells to make antibodies without the aid of helper T cells; polysaccharides of the bacterial capsule
Term
Susceptibility
Definition
Lack of resistance to a disease
Term
Resistance
Definition
Ability to ward off disease
Term
Non-specific resistance
Definition
Defenses against any pathogen
Term
Specific resistance
Definition
Immunity to a specific pathogen
Term
First line of defense
Definition
1) Skin (dermis and epidermis): mechanical and chemical
2) Mucous membranes: mechanical and chemical
3) Normal microbiota
Term
What are some examples of mechanical muscous membrane defenses?
Definition
1) Mucus: microbes trapped in mucus are transported away from the lungs
2) Lacrimal apparatus: washes eye
3) Saliva: washes microbes off
4) Ciliary escalator: cilia propel microbes trapped in mucus toward the throat
Term
What are some chemical examples of defense?
Definition
1) Sebum: fatty acids inhibit the growth of bacteria and fungi; low pH of skin
2) Lysozyme in fluids break the chemical bonds on peptidoglycan
3) Low pH of stomach acid
4) Transferrins (iron binding protein) in blood
Term
How do normal microbiota act as a defense?
Definition
Microbial antagonism or competitive exclusion; inhabit all possible niches of the human body and compete with pathogens for habitat and available nutrients
Term
What is phagocytosis? Explain how it relates to human defenses against pathogenic microbes.
Definition
The ingestion of microbes or particles by a cell
Phagocytes ingest invading microbes to digest and neutrolize them
Term
What are the four stages of phagocytosis?
Definition
1) Chemotaxis
2) Adherence
3) Ingestion
4) Digestion
Term
Chemotaxis
Definition
chemical attraction
Term
Adherence
Definition
attachment to the plasma membrane of the phagocyte
Term
Ingestion
Definition
with the help of pseudopods and form phagosomes (phagocytic vesicles)
Term
Digestion
Definition
1) Phagosome enters the cytoplasm, meet with lysosomes forming phagolysosome
2) Lysozyme and other enzymes hydrolyse the bacterial components
3) Lysosomes produce toxic oxygen products by a process called "oxidative burst"
4) Residual body is discharged from the cell
Term
What are the two main types of white blood cells that perform phagocytosis in the human body?
Definition
1) Neutrophils
2) Macrophages?
Term
Phagocytosis comes under which line of defense?
Definition
Second
Term
Give two examples of microbial evasion of phagocytosis.
Definition
1) Escape phagosome: Shigella
2) Prevent phagosome-lysosome fusion:HIV
3) Survive in phagolysosome: Coxiella burnetti
Term
What is inflammation?
Definition
Defensive response to the damaged body tissues
Term
What are five signs of inflammation?
Definition
1) Redness
2) Pain
3) Heat
4) Swelling (edema)
5) Loss of function
Term
Inflammation comes under which line of defense?
Definition
Second
Term
What are the three functions of inflammation?
Definition
1) Destroy the agent causing the disease
2) Limit the effect
3) Repair
Term
What are the three stages of inflammation?
Definition
1) Vasodilation
2) Phagocyte migration and phagocytosis
3) Tissue repair
Term
Three functions of vasodilation
Definition
1) Increase blood flow to the damaged area cause redness (erythema), heat and pain
2) Blood clots prevent the microbe from spreading
3) Localize collection of pus and dead cells (abcess)
Term
Four characteristics of phagocyte migration and phagocytosis.
Definition
1) Phagocytes appear on the scene within an hour
2) Phagocytes begin to stick to the lining of blood vessels (margination)
3) Phagocytes squeeze between the blood vessel cells and reach the damaged area (emigration or diapedesis)
4) Phagocytes begin to destroy the invading microbes
Term
Three characteristics of tissue repair.
Definition
Epidermis or dermis produces new cells
1) Depends on the type of tissue:
skin-regenerate faster
heart muscle-does not regenerate
2) Tissue is repaired when epidermis or dermis produces new cells
3) If dermal cells are more active than the epidermal cells, scar tissue is formed
Term
What are the four chemicals released by damaged cells that are responsible for vasodilation?
Definition
1) Histamine
2) Kinins
3) Prostaglandins
4) Leukotrienes
Term
What is margination?
Definition
Phagocytes begin to stick to the lining of blood vessels
Term
What is emigration (diapedesis)?
Definition
Phagocytes squeeze between the blood vessel cells and reach the damaged area
Term
Chills and shivering is a sign that?
Definition
1) Body has increased rate of metabolism to raise temperature
2) Gram-negative endotoxin causes release of interleukin-I
Term
Crisis and sweating is a sign that?
Definition
IL-1 is eliminated body temperature falls
Term
Fixed macrophages (histiocytes)
Definition
Found in lungs, liver, bronchi, nervous system, spleen, lymph nodes, bone marrow
Term
Wandering macrophages
Definition
roam tissues; gather at sites of infection
Term
What are five conditions in which phagocytosis can be less effective?
Definition
1) Born with an inability to produce phagocytes
2) Progressive decline with age
3) Recipients of heart and kidney transplants
4) Radiation treatments
5) Aids and cancer patients
Term
Name an antimicrobial substance that is involved in our second line of defense and how does it work.
Definition
Gamma interferon: causes neutrophils and macrophages to phagocyte bacteria
Term
Describe the complement system
Definition
Over 30 proteins produced by liver and found circulating in the blood serum; number C1-C9, serum proteins are activated in a cascade, for example C5-C9 cause cytolysis
Term
Three characteristics of complement system
Definition
Opsonization or immune adherence: enhanced phagocytosis
Membrane attack complex (MAC): cytolysis
Attract phagocytes
Term
Three ways bacteria evade complement.
Definition
1) Capsules prevent Complement activation
2) Surface lipid-carbohydrates prevent MAC formation
3) Enzymatic digestion of complement proteins
Term
Interferons are produced...
Definition
after viral infections by fibroblasts (found in the connective tissues) and leukocytes
Term
Three characteristics of interferons.
Definition
1) Small proteins
2) Interfere with viral multiplication
3) Host cell specific but not virus specific
Term
What are the three principal types of human interferons?
Definition
1) Alpha IFN
2) Beta IFN
3) Gamma IFN
Term
Alpha IFN and Beta IFN
Definition
cause cells to produce antiviral proteins that inhibit viral replication; produced by the virus infected cells
Term
Gamma IFN
Definition
Causes neutrophils and macrophages to phagocyte bacteria; produced by lymphocytes
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