Innate Immune System
Present at birth
Rapid response
Nonspecific
No memory response
Adaptive Immune System
Waits for trigger
Slower response
Specific
Memory response
First Lines of Defense (Innate)
Intact skin
• Mucous membranes and their secretions
• Normal microbiota
2nd line of Defense (Innate)
• Phagocytes, such as neutrophils, eosinophils, dendritic cells, and macrophages
• Inflammation
• Fever
• Antimicrobial substances
3rd Line of Defense (Adaptive)
• Specialized lymphocytes: T cells and B cells
• Antibodies
Lysozyme
enzyme that can break down cell walls of bacteria found in perspiration, tears, saliva, urine, nasal secretions, tissue fluids
Sebum
protective film, low pH
Mucous Membranes
Line the respiratory, GI, GU tracts Prevent drying out
Trap microbes
Ciliary escalator
GOBLET CELLS PRODUCE MUCOUS
Physical Protection Factors
Lacrimal apparatus-tears Saliva
Earwax and hairs Secretions
Urine flow
Epiglottis
Peristalsis, defecation, vomiting, diarrhea
Chemical Protection Factors
Sebum, Lysozymes, Ear wax, Saliva, Gastric, Vaginal secretions, Urine
Bacteriocins:
Produced by microbiota, inhibit growth of other bacteria
Leukocytosis:
increase in WBC count
Leukopenia:
decrease in WBC count
3 types of Lymphocytes
T Cells
B Cells
Natural Killer Cells
perforin:
cytolysis
granzymes:
apoptosis
What are the differences between innate and adaptive immunity?
adaptive immunity The ability, obtained during the life of the individual, to produce specific antibodies and T cells,
innate immunity Host defenses that afford protection against any kind of pathogen. See also adaptive immunity.
What are our first, second, and third line defenses against pathogens?
How do skin and mucous membranes protect us?
SKIN - Closely packed cells, Continuous shedding of outer layer, Keratin-protective protein on outer layer, Dry
Mucous - Line respiratory, GI, GU, Prevents drying out, traps microbs, Cilliary escalator
What is the ciliary escalator?
Beating of cilia to move bad stuff out.
How does normal microbiota protect us?
Compete for attachement/nutrients (microbial antagonism)
Produce bacteriocins that inhibit growth of other bacteria
Lower pH
Simulate/Shape Immune System
What are some other physical barriers?
Lacrimal apparatus-tears Saliva
Earwax and hairs Secretions
Urine flow
Epiglottis
Peristalsis, defecation, vomiting, diarrhea
What are some Chemical barriers?
Sebum
Lysozyme
Ear Wax
Saliva
Gastric Juice
Vaginal secretions
Urine
What is lysozyme?
enzyme that can break down cell walls of bacteria found in perspiration, tears, saliva, urine, nasal secretions, tissue fluids
What kind of leukocytes are phagocytes?
Monocytes/Macrophage, Eosinophil, Neutrophil
Which cell can become a macrophage?
Monocytes
Which kind of WBC would you expect to be first at the site of an infection?
Neutrophil
Which one would you expect to see increased in an allergic reaction or parasitic infection?
Allergic (Basophil/Eosinophil), Parasitic (Eosinophil)
Which one can be T and B cells?
Lymphocytes
What are NK cells?
natural killer (NK) cell A lymphoid cell that destroys tumor cells and
virus-infected cells. (RAMBO/ NON-SELF)
What kind of enzymes do NK produce and what are the functions?
Perforin - Cytolysis (Holes in membranes)
Granzymes - Apoptosis
What are dendritic cells?
A type of antigen-presenting cell characterized by long finger like extensions; found in lymphatic tissue and skin,
What are TLRs?
(Toll-like receptor) Transmembrane protein of immune cells that recognizes pathogens and activates an immune response directed against those pathogens.
Where do you find TLRs?
Phagocytes
What are PAMPs?
pathogen-associatcd molecular patterns) Molecules present on
pathogens and not self
Where would you find PAMPs?
Microbes
What are some examples of PAMPs?
LPS, flagellin, DNA & RNA of viruses, peptidoglycan
How do TLR/PAMP aid in phagocytosis?
Chemotaxis & Adherence
What is opsonization?
opsonization The enhancement of phagocytosis by coating microorganisms with certain serum proteins (opsonins); also called immune adherence,
What is a phagosome? Lysosome? Phagolysosome?
phagosome A food vacuole of a phagocyte; also called a phagocytic vesicle,
lysosome An organelle containing digestive enzymes.
phagolysosome A digestive vacuole.
What is the role of the lymphatic system as a second line of defense?
Second circulatory system
Fluid and pathogens from tissues swept into lymphatics
Innate and adaptive immune cells gather at lymph nodes and sample lymph looking for infection
Drains back into blood near heart
What is inflammation?
inflammation A host response to tissue damage characterized by redness,pain, heat, and swelling; and sometimes loss of function,
What are the signs (rubor, calor, etc)?
Rubor (redness)
Calor (warmth)
Tumor (swelling)
Dolor (pain)
Loss of function
What is the purpose of inflammation?
Increase of blood vessel permeability and chemotactic attraction of phagocytes
Functions of inflammation
To destroy injurious agent and remove it from body
Limit the effects on the body Repair and replace tissue damaged
What are margination and diapedesis?
margination The process by which phagocytes stick to the lining of blood vessels,
diapedesis The process by which phagocytes move out of blood vessels,
What is the role of cytokines in inflammation?
Increases permeability of blood vessels
What is edema?
edema An abnormal accumulation of interstitial fluid in body parts or tissues, causing swelling
What is pus?
an accumulation of dead phagocytes, dead bacterial cels, and fluid,
What is chemotaxis?
movement in response to the presence of a chemical,
How does fever aid in fighting an infection?
Speeds up metabolism for quicker tissue repair Decreases iron available to microbes
Increase production of T cells
Intensifies effect of interferons
Inhibits multiplication of temperature-sensitive microbes
Can cause seizures and death if too high
What is a pyrogen?
Pyrogen: molecule which induces fever (may be internal or external)
Cause hypothalamus to reset body’s thermostat
What is complement?
complement A group of serum proteins involved in phagocytosis and lysis of bacteria and inflammation.
What is the role of complement in defense of the body (3 main functions)?
1. - Cytolysis
2. - Phagocytosis
3. - Inflammation
What does “complement cascade” mean?
Cascade-one reaction triggers another
Know the following
Complement molecules need to be split apart to be activated. C3b opsonizes invading bacteria. C3a and C5a are important in inflammation.
What are the 3 complement pathways?
Classical
Alternative
Lectin
What type of microbes does interferon protect against?
viruses
Interferon (IFN) A specific group of cytokines. Alpha- and beta-IFNs are antiviral proteins produced by certain animal cells in response to a viral infection. Gamma-IFN stimulates macrophage activity,
What cells release interferons?
Virus Infected cells (it’s too late for me, save yourselves)
Know how adaptive immunity is different from innate.
What are antigens? Epitopes? Haptens?
specific region on the surface of an antigen against which antibodies are formed; also called epitope,
hapten A substance of low molecular weight that does not cause the formation of antibodies by itself but does so when combined with a carrier
Know the structure of a typical antibody molecule.
Which class is the first response to an infection?
In mucous membranes?
Which class is the highest in the whole body?
In blood serum?
In parasitic and allergic reactions?
IgM
IgA
IgA
IgG
IgE
What is the difference between humoral and cellular immunity?
What kind of cells are T & B cells?
Lyphocytes.
Where are each differentiated? B - Red Bone Marrow, T-Thymus
What kind of immunity is each kind most associated with? B- Humoral, T- cellular
Which ones can become plasma cells? B- Cells
Which kind of cell is coated with antibodies? B-cells
What are APCs?
antigen-presenting cell (APC) A macrophage, dendritic cell, or B cell that engulfs an antigen and presents fragments to T cells.
What does MHC stand for?
major histocompatibility complex (MHC) The genes that code for histocompatibility antigens; also known as human leukocyte antigen (HLA) complex.
Briefly, what is the difference between class I and class II?
Which class MHC would you expect to be active in a viral infection?
MHCI
What kind of T cells bind to each MHC?
MHCI - CD8, MHCII CH4
What are T(H) cells? What are they needed for?
T helper (Th) cell activate T-dependent B Cells
Bind w/ MHCII on APC to activate APC, and T(c)
What does it mean if a B cell is T-independent?
T-independent antigen An antigen that will stimulate the formation of antibodies without the assistance of T helper cells. See also T-dependent antigen,
T-dependent antigen An antigen that vnll stimulate the formation of antibodies only with the assistance of T helper cells. See also T-independent antigen,
What is clonal expansion and selection?
clonal selection The development of clones of B and T cells against a specific antigen.
What is class switching?
class switching Ability of a B cell to produce a different class of antibody against one antigen.
What are 5 results of antigen-antibody binding?
1. Agglutination
2. Opsonization
3. Activation of complement
4. Antibody-dependent cell-mediated cytotoxicity
5. Neutralization
What kind of cells would be involved in trying to rid the body of large pathogens such as protozoa?
Eosinophils
Know the difference between naturally and artificially acquired adaptive immunity. Within each of these, what is the difference between active and passive immunity?
What is the purpose of vaccination?
to establish herd immunity in populations
What is the difference between the primary and secondary response to a pathogen?
Secondary response produces higher level of antibodies in serum
What are the different kinds of vaccines?
Killed
Attenuated
Toxoids
Subunit
Conjugate
DNA - Non-fridge
What does attenuated mean?
attenuated vaccine A vaccine containing live, attenuated (weakened) microorganisms.
What are toxoids?
Toxoids – These are inactivated toxic compounds secreted by the organism.
What benefits does attenuated have over killed vaccines?
Mimic actual infection
lifelong immunity, very effective, induces cellular and humoral immunity
What is a conjugated vaccine?
Conjugate vaccines – These contain the polysaccharide outer coats combined with proteins or toxins.
Ex. Haemophilus influenzae type B vaccine.
What is oxidative or respiratory burst?
REDOX/Free radical to rupture.
How do cytotoxic T cells kill infected cells? What kinds of chemicals are used?
Perforin
Granzymes
What is apoptosis?
programmed cell death controlled, regulated death ready-to-go in all of our cells,they just need the trigger
What are some ways that pathogens can evade phagocytosis?
Inhibit adherence- capsules, M proteins
Biofilms
Enzymes that kill phagocytes – leukocidins
Some microbes can survive inside phagocyte Mycobacterium tuberculosis,
Release of toxins that lyse phagocyte cell membranes
What is the VAERS?
Vaccine Adverse Event Reporting System