Exam 3 Dr. Nick Peters Microbiology 201 Iowa State University

Lymph System

Separate vessel system which transport fluids and protect from infections

white blood cells (leukocytes)

respond to injury or infection

neutrophils

Most abundant white blood cell, essential to the immune system

eosinophils

type of white blood cell that usually indicates a parasite

basophils

A circulating leukocyte that produces histamine.

histamine

Chemical stored in mast cells that triggers dilation and increased permeability of capillaries.

macrophages

Found within the lymph nodes, they are phagocytes that destroy bacteria, cancer cells, and other foreign matter in the lymphatic stream.

phagocytes

White blood cells that attack invading pathogens

lysozymes

enzyme that damage bacterial cell walls

mucocillary escalator

when the underlying cilia in the mucosal layer of the respiratory tract traps the larger bacteria or material and propels it into the oral cavity where it can be swallowed or expelled

interferon

one of a group of proteins that help cells resist viral infection

complement system

proteins in the blood that help antibodies kill their target

pathogen-associated molecular patterns

endotoxins found on the cell membranes of gram-negative bacteria

Pathogen recognition receptors (PRRs)

cellular receptors for microbial antigens on innate immune cells

cytokines

proteins secreted by cytotoxic T cells to aid in antigen destruction

chemotaxis

movement of a motile cell or organism, or part of one, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance.

inflammation

a localized response to an injury or to the destruction of tissues

phagocytosis

Cell eating

opsonization

An immune response in which the binding of antibodies to the surface of a microbe facilitates phagocytosis of the the microbe by a macrophage

First line of defense

skin and mucous membranes

second line of defense

protective cells and fluids; inflammation and phagocytosis - nonspecific

third line of defense

immune system

What are the physical and chemical factors that are important in the first line of defense?

skin, tears, mucus, cilia, stomach acide, urine flow, friendly bacteria, and neutrophils

What are the events that take place in an inflammatory response?

Vasodilation: leads to greater blood flow to the area of inflammation, resulting in redness and heat.

Vascular permeability: endothelial cells become "leaky" from either direct endothelial cell injury or via chemical mediators.

Exudation: fluid, proteins, red blood cells, and white blood cells escape from the intravascular space as a result of increased osmotic pressure extravascularly and increased hydrostatic pressure intravascularly

Vascular stasis: slowing of the blood in the bloodstream with vasodilation and fluid exudation to allow chemical mediators and inflammatory cells to collect and respond to the stimulus.

phagocytic cells

neutrophils and macrophages

How does interferon help protect against virus infection?

stimulates protein to prevent the virus from replicating

In non-technical terms, describe what the complement system is and what it does to protect us against infections.

system of plasma proteins activated by infection, pathogens, disease, that activate the components of the immune system required to fight off infections.

B lymphocytes

form in the bone marrow and release antibodies that fight bacterial infections

T lymphocytes

form in the thymus and other lymphatic tissue and attack cancer cells, viruses, and foreign substances

dendritic cells

specialized white blood cells that patrol the body searching for antigens that produce infections

macrophage

large phagocyte found in lymph nodes and other tissues of the body

plasma cell

a fully differentiated B cell that produces a single type of antibody.

helper T-Cell

a T cell that influences or controls the differentiation or activity of other cells of the immune system.

cytotoxic t-cell

lymphocyte that directly kills antigens

regulatory t-cell

turns off the immune response when the "enemy" has been routed

clonal selection

antigens bind to specific receptors, causing a fraction of lymphocytes to clone themselves

lymphocyte maturation

B cells mature in bone marrow

T cells mature in thymus

antigen

substance that triggers an immune response

antibody

A protein that acts against a specific antigen

T cell receptor

The antigen receptor on T cells; a membrane-bound molecule consisting of one α chain and one β chain linked by a disulfide bridge and containing one antigen-binding site.

MHC receptors

markers on Cell surfaces for recognizing self

memory cell

A lymphocyte that responds to an antigen upon reintroduction

b-cell activation

Antigen binding by surface IgM or IgD, results in maturation to IgM or IgD secreting plasma cells. No second signal needed if enough antigen present to activate and cross link Ig's or antigen activates TLR. Alternate Pathway B-cell presents antigen to Th2 T-cell via MHC II -- CD40 receptor on B cell binds CD40L on Th2 as 2nd signal -- Th2 secretes IL-4 and IL-5 to mediate isotype switching, hypermutation and plasma cell maturation.

T-cell activation

the stimulation of mature naive T cells by antigen presented to them by professional antigen-presenting cells. It leads to their proliferation and differentiation into effector T cells.

antigen presenting cell

A cell that displays foreign antigens with major histocompatibility complexes on their surfaces

neutralization with antibodies

defends the body by neutralizing the threat biologically

primary immune response

the initial immune response to an antigen, which appears after a lag of several days

secondary immune response

Immune response after the body has already been exposed to a specific antigen. Response is faster, of greater magnitude, and more prolonged.

Specificity

The ability of adaptive immunity to recognize a particular substance

memory

The ability of adaptive immunity to "remember" previous encounters with a particular substance so it can destroy it more efficiently

How are we able to produce such a huge number of antibody specificities?

affinity maturation

Where are antibodies produced?

lymph nodes

antigen presenting cells

dendritic cells, macrophages, B cells

antigen presentation

The process by which an MHC molecule binds to a fragment of an intracellular protein antigen and carries it to the cell surface, where it is displayed and can be recognized by a T cell.

active immunity

immunity produced by exposure to an antigen, as a result of the immune response

passive immunity

the short-term immunity that results from the introduction of antibodies from another person or animal.

natural immunity

Immunity that is partly inherited and partly developed through healthy living.

artificial immunity

immunization; immunity acquired from a vaccination

vaccine

substance prepared from killed or weakened pathogens and introduced into a body to produce immunity

live vaccine

The pathogen injected into your body is alive, but weakened. Sometimes makes you a little sick

attenuated vaccine

a weakened or dilute solution of microbes

subunit vaccine

Vaccine containing only specific antigenic proteins of the infectious agent

DNA vaccine

a vaccine that is made from the DNA of a pathogen and that does not have disease-causing capabilities

fluorescent antibody

an antibody molecule covalently modified with a fluorescent dye that makes the antibody visible under fluorescent light

agglutination test

a procedure in which antiserum is mixed with a sample that potentially contains its target antigen

ELISA test

Enzyme-Linked immunosorbent assay, diagnose HIV

Serological tests

Detect antibodies against viruses in a patient

Use antibodies to identify viruses in neutralization tests, viral hemagglutination, and Western blot

precipitation test

antigen is made insoluble by an antibody, creates cloudy zone

monoclonal antibody

antibody produced in a laboratory to attack antigens and to destroy cells; useful in immunotherapy

antiserum (polyclonal antibody)

They are a collection of immunoglobulin molecules that react against a specific antigen, each identifying a different epitope.

Lateral Flow Immunoassay

A sample that contains antigen flows through a porous strip, and positive reactions are shown by the appearance of a colored band

herd immunity

The resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune

disease

An abnormal state in which the body is not functioning normally

epidemiology

the branch of medicine that deals with the incidence, distribution, and possible control of diseases and other factors relating to health.

zoonosis

An infectious disease that is transmissible from animals to humans.

reservoir

Any person, animal, plant, soil or substance in which an infectious agent normally lives and multiplies

pathogenicity

ability of a microorganism to cause disease

pathogenesis

the manner in which a disease develops

virulence

degree of pathogenicity

infectious dose

the number of microorganisms or viruses sufficient to establish an infection

ID50

infectious dose for 50% of the test population

acute

measure of the time scale of a disease (short)

chronic

disease exists over a long time

latent disease

causative agent is inactive for a time but then activates and produces symptoms

communicable disease

a disease that is spread from one host to another

non-communicable disease

a disease not capable of being spread from one person to another

contagious disease

a disease that is easily spread from one host to another

asymptomatic disease

disease without signs or symptoms

vector

agent that carries and transmits an infectious pathogen into another living organism

surveillance

ongoing and systematic collection, analysis and interpretation of health data

prevalence

The number or proportion of cases of a particular disease or condition present in a population at a given time.

incidence

number of new cases

mortality

the state of being subject to death

morbidity

Refers to ill health in an individual and the levels of ill health in a population or group.

endemic

confined to a particular country or area

pandemic

worldwide epidemic

epidemic

regional outbreak of a disease

nosocmial

infection aquired by an individual in a health care facility such as a hospital or long-term care facility

symptom vs sign

Symptom = subjective; Sign = objective

primary vs opportunistic pathogen

A. Primary pathogen - When we have them, Will always cause infection/disease

1) i.e. the flu

B. Opportunistic pathogen - Commensal organism that is allowed into protected sites.

1) i.e. Staph epidermidis (catheters can transmit this if not properly used and sterilized; increased resistance in hospitals now)