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microbiology - Test 3; Immunity I-IV
BIO 2400
95
Microbiology
Undergraduate 2
04/19/2011

Additional Microbiology Flashcards

 


 

Cards

Term
Susceptibility
Definition
lack of resistance to a disease
Term
Immunity
Definition
Ability to ward off disease
Term
Innate Immunity
Definition

born with; defenses against any pathogen; general

first and second line of defense

 

Term
Adaptive Immunity
Definition
Resistance to a specific pathogen
Term

Innate Immunity: Physical First line Defense

skin

Definition
cells tightly packed together; dry skin flakes off
Term

Innate Immunity: Physical First line Defense

Mucus Membranes

Definition

Membrane: also epitheal layer

Mucus: Viscous glycoprotein material keeps membrane from drying

Lacrimal apparatus: tear ducts; tears

Cilia: sweep microbes up from lower respiratory tract

Others: hair, urine flow, vaginal secretions, defication, vomiting, peristalsis

Term

Innate Immunity: Chemical First line Defense

 

Definition

Sebum: fatty acids inhibits microbial growth; secreted by sebacious glands

Lysozymes: break down petidoglycan; tears, urine, sweat

Gastric Juice: very low pH is inhibitory; Helicobacter pylori-stomach ulcers

Term

Innate Immunity: Chemical First line Defense

 

Definition

Urine: low pH; lysozymes

Vaginal Secretions: low pH is inhibitory

Normal Flora: use nutrients; produce inhibitory compounds;

#bacterial cells > #human cells

Term

Innate Immunity: Second line Defense

 

Definition
Circulatory system; blood and lymph
Term

Innate Immunity: Second line Defense

Leukocytes

Definition

Neutrophils: phagocytosis

Basophiles: Histamine; allergic reactions

Eosinophils: selective for parasites

Monocytes (Macrophages): best phagocytes

Term

Innate Immunity: Second line Defense

Leukocytes

Definition

Dendritic cells: phagocytosis

Natural Killer cells: Destroy target cells


*T-cells: cell-mediated immunity
*B-cells: produce antibodies

*=3rd line defense

Term

Innate Immunity: Second line Defense

Lymphatic System

 

Definition

Lymph: Fluid

Lymphoid Tissue: ex. tonsils

Red Bone Marrow: blood cell origin

Lymphatic Vessels: carry lymph and blood

Term

Innate Immunity: Second line Defense

Phagocytosis

 

Definition

Ability to ingest microorganisms

 

Term
Bacterial defenses against phages
Definition

capsule

toxins

biofilm formation: extracellular matrix

hide inside phagocyte

Term

Second Line Defense

Inflammation

Definition

Cytokines released; recruit phagocytes

Redness/Heat: increased permeability and vasodilation; cells can leave vessel and enter tissue

Pain/Swelling: increased blood and pressure; nerve damage

Term

Second Line Defense

Fever

Definition

Cytokines travel to brain:

hormone-like molecules; reset (increase) body temp

Rate of metabolism increased; shivering

Decrease availible Iron

Decrease Doubling time of bacteria w/ increased body temp


Term

Second Line Defense

Antimicrobial Substances

Complement System

Definition

30+ proteins complement innate and adaptive immunity

Proteins kept inactive; due to high potency

 

Term
Activated Complement System
Definition

C3a C3b = activated proteins (lower case)

Cytolysis: makes holes in bacterial membrane; cell lysis

Enhance Inflammation: proteins stimulate histimines that bind to bacterial cell

 

Term

Activated Complement System

Opsonization

Definition

Opsinization = Enhanced phagocytosis

Protein coats bacteria

Term

Second Line Defense

Antimicrobial Subtances

Interferons

Definition

Antiviral properties; interfere with viral replication

Infected cell releases interferons that bind to healthy cells "paul revere"

Healthy cells produce antiviral proteins

Term

Second Line Defense

Antimicrobial Subtances

Iron Binding Proteins (IBP)

Definition

IBP keep Fe from siderophores

Transferrin: blood in tissue

Lactoferrin: milk, saliva, mucus

Ferritin: liver, spleen, bone marrow

Hemoglobin: RBCs

Term

Second Line Defense

Antimicrobial Substances

Antimicrobial Peptides

Definition

Peptides (NOT proteins) produced by host cells

Synthesis is triggered by proteins or sugars on a pathogen’s surface

broad spectrum

Term

Second Line Defense

Antimicrobial Substances

Antimicrobial Peptides:

Modes of Action

Definition

Inhibit cell synthesis

form pores in pathogen's membrane

destroys pathogen's DNA/RNA

No bacteria resistant

Term
Adaptive Immunity
Definition

stem cell splits

Humoral: differentiates in bone marrow; B-cell

Cell mediated: differentiates in Thymus; T-cell

Term
Active Humoral Immunity
Definition
produced by host in response to antigen
Term
Passive Humoral Immunity
Definition

received from donor;

breast milk, placental transfer

Immune serum; anitivenom

Term
Antigen (ag)
Definition
substance that generate immune response:
Term
Types of Antigens
Definition

capsule

peptidoglycan

flagella

bacterial toxins

pollen

transplanted tissue/blood

Term
Epitope
Definition

portion of ag that reacts with antibody;

aka antigenic determinant

Term
Hapten
Definition
small molecule with an epitope; immune response only when attached to a large carrier (protein
Term
Adjuvant
Definition
substance to increase immunogenicity (ability to invoke immune response)
Term
Antibodies
Definition
a compact globular protein produced in response to an antigen; aka Immunoglobulin
Term
Antigen binding sites
Definition
recognize and bind to antigenic determinants
Term

Antibiotic Classes

IgM

Definition
{image:|}
Term

Antibiotic Classes

IgG

Definition

follows IgM; most common in serums

Functions:
–Enhance phagocytosis by opsonization
–Neutralize toxins and viruses
–Binds complement

Protects fetus/newborn; passive immunity

Term

Antibiotic Classes

IgA

Definition

Found in secretions

Function:
–Newborn protection against GI pathogens by colostrum (first breast milk)
–Neutralizes/inhibits entry of pathogens through mucous membranes

Term

Antibiotic Classes

IgD

Definition

Found on surface of some lymphocytes

Function:

helps activation of lymphocytes

Term

Antibiotic Classes

IgE

Definition

Found on mast and basophil cells

Function:

Allergic Reactions

Parasitic worm infections

Term
Ag/Ab Binding
Definition
Ab tag pathogens by complement/phagocytes
Term

Ag/Ab binding

Agglutination

Definition

Enhances Phagocytosis (reducing #infectious units);

Ag bind 2-3 bacterial cells together

Term

Ag/Ab binding

Opsonization

Definition

enhances phagocytosis;

Coats bacteria with antibodies

Term

Ag/Ab binding

complement activation/fixation

Definition

Antibodies act like flags;

inflammation and cell lysis

Term

Ag/Ab binding

Antibody-dependent cell-mediated immunity

Definition

attaches to larger target cells (parasites);

destruction by:

eosinophils: release perforic/lytic enzymes

 macrophages

NK cells

 

Term

Antibody Production

B-cells

Definition

origin: bone marrow

contains specific ab on surface thats binds to specific epitope

 

Term
Clonal Expansion
Definition
activated B-cell secretes antibodies that target pathogen
Term

B-cell Activation

T-cell independent

Definition

less common

polysaccharide (T-independent ag) has multiple binding sites

Term

B-cell activation

T-cell dependent

Definition

more common

B-cell "chews" up antigen

MHC class II molecule displays antigen fragments on b-cell surface

T-cell confirms antigen and releases cytokines

Term
Memory Cells
Definition

Clonal selection: b-cells from expansion formed into plasma or memory cells; preventative measure - quicker response

 

Term
Activation Location
Definition
B-cells, T-cell, phagocytes interact in lymph tissue
Term
Antibody effectiveness
Definition
most effective against extracellular pathogens
Term
Antibody production
Definition
Upon activation: B-cells become plasma and IgM ab first
Term
isotype switching
Definition
B-cell→IgM→Ig...
Term
Primary Immune Response
Definition
[image]
Term
Secondary immune Response
Definition
[image]
Term

T-cells

Cell-mediated immunity

Definition

fight intracellular pathogens

enhanced phahocytosis

respond to tumor cells

transplant rejection

Term
T-cells
Definition

oringinate in bone marrow; mature in thymus

T-cell receptors recognize specific antigen

Activated by "Antigen presenting cells" (b-cell displaying antigen)

Term

T-cell Classes

T-helper (TH) cells

Definition

release cytokines that activate b-cells against extracellular pathogens;

antigen interaction: MHC Class II

Term

T-cell Classes

Cytotoxic (TC) cells

Definition

 Antigen interaction: MHC Class I; marks cell as "self"

ags tag infected cells; non-self

Controlled destruction of infected cells; shrivel

Term

T-cell Classes

T-Suppressor (TS) cells

Definition

recognize "self" antigens

Immune Tolerance:

Term

T-cell Classes

T memory (TM) cells

Definition

Recognize previous T-dependent antigens (extracellular)

Results in fast secondary immune response

Term

Non- T/B immune cells

Natural Killer cells

Definition

Non-phagocytic lymphocytes; induce apoptosis (controlled cell death)

Additional help: virus infected cells/tumor cells

 

 

Term
Measurement of Immune Response
Definition

Blood cell count: # WBC, RBC, platlets

Antibody Count: Titer test (#abs)

Cytokine Levels

Agglutination Reaction: blood typing, prego

Hypersensitivity: allergen skin test

 

Term
Other uses for abs
Definition

Vaccines

ID of microbes

Immunoblotting

Term

Immune System problems

Autoimmunity

Definition

immune reaction against self; sees host cells as pathogenic

ex. MS, Rheumatoid arthritis, Type I diabetes

Term

Immune System problems

Ineffectiveness

Definition

occurs when some pathogens are not killed; hide inside host

ex. mycobacteria "TB", legionella, listeria

Biofilms also resistant

Term

Immune System problems

loss-all/part

Definition

AIDS

Genetic disorders = reduced life expectancy (often before 5)

Severe combined immunodeficiency (low B and T cell levels)

Term
AIDS
Definition

Diagnosis: appearance of second infection; antibody titer against HIV

Retrovirus HIV infects (TH) cells; specific immunity

adapted immunity wiped out

susceptibility of secondary infection is main COD

Term

Immune System problems

Hypersensitivity

Definition

excessive immunological response to antigen

Allergy: immune response to allergen

Term

Type I

Immediate/anaphylactic Hypersensitivity

Definition

fast; 5-30 min

ex. hay fever/bee sting allergies

Term

Type II

Antibody Dependent cytotoxic Hypersensitivity

Definition

antibody combines with cell

ex. blood group incompatibilty

Rh factor

 

Term

Type III

Immune-complex hypersensitivity

Definition
Immune complex: Small particulate ab-ag combination; stimulates rest of immune system causing tissue/cell destruction
Term

Type IV

Delayed or Cell-mediated hypersensitivity

Definition

1-3 days after exposure

ex. TB skin test, poison ivy

Term
Koch' Postulates
Definition

1. Same pathogen must be present in every case of the disease
2. Pathogen must be isolated from the diseased host and grown in pure culture

3. The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible lab animal
4. The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.

Term
Pathogenicity
Definition

ability of an organism to cause disease

possess weapons aka virulence factors

Term
Infectious Dose
Definition
# of bugs required to cause infection
Term
Acute Infection
Definition

short/severe

ex. strep throat

Term
Chronic Infection
Definition

Prolonged

ex. TB

Term
Fulminating infection
Definition

sudden/intense

ex. meningitis

Term
Primary Infection
Definition

initial infection

Flu/HIV

Term
Secondary Infection
Definition

occurs after primary by oppurtunisitic pathogens

ex. pneumoniae following flu

Term
Bacterimia
Definition

presence of bacteria in blood

Septicemia: bacteria growing in blood

Term

Steps to cause disease

Entry

Portal of Entry

Definition

Membranes/skin

Parenteral: direct deposition beneath skin or mucous membranes

*most pathogens have preferred POE

Term

Steps to cause disease

Entry

Adherence

Definition

Adhesins (Ligands): bind pathogen to specific receptors in host

 

Term

Steps to cause disease

Entry

Penetration

Definition

Active: pathogen has own mechanism for penetration

Passive penetration: organism penetrates tissue due to wound, burn, insect bite, animal bite, etc.

Term

Host:

Immune recognition of epitopes on pathogen surface

Definition

Pathogen:

capsule hides cell surface; resist phagocytosis 

eleminates unnecessary components 

Antigenic phase variation: bacteria changes ags

Molecular Mimicry: pathogens decorate surface that mimic host cell surfaces

 

Term
Host: Leukocytes
Definition
Pathogen: secretes Leukocidin to kill leukocytes/ some live inside leukocyte
Term

Bacterial Pathogens

Penetration into Cytoskeleton

Definition

bacteria use Actin for movement in cytoskeleton

 

Term
Host: Immunoglobulins
Definition

Pathogens secrete protease to digest antibodies

ex. Ig protease

Term

Host:

Low Nutrient Level

Definition

Pathogens:

produce siderophores; "Fe boomerang"

Select best habitat for colonization; richer nutrient area

Term

Host:

Protection from tissue surface or mucus layer

Definition

pathogen:

secrete enzymes to break down surface

Term
Normal Flora
Definition

pathogen:

competes for nutrients

adapts to less favorable nutrients

Term

Damage to Host Cells by Bacterial Pathogens

Direct Damage

Exoto

Definition

Exotoxins: produced by bacteria; secreted proteins- small amount needed

ex. tetanus, botulism

Endotoxins: within LPS released upon death; GRAM NEGATIVE

ex. Typhoid fever and N. meningitidis

 

Term
Exotoxins
Definition

 Source: Gram +

Relation to microbe: by-products of cell

Chemistry: Protein

Fever? No

Neutralized by Antitoxin? Yes

Lethal Dose: small

Term
Endotoxins
Definition

Source: Gram –

Relation to microbe: outer membrane

Chemistry: Lipid A

Fever? Yes

Neutralized by Antitoxin? No

Lethal Dose: ~large

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