-adaptive

-innate

-initiated in response to invasion of the body by a microbe

-slower

-has a memory

-uses T and B lymphocytes

-present at birth

-first line of defense

-second line of defense

-skin

-mucous membranes

-normal flora

-white blood cells

-inflammation

-fever

-antimicrobial substances

-intact skin cannot be invaded

-broken skin allows entry of Staph. and other bacteria that live on skin

-sebum - produced by oil glands, contains fatty acids and lactic acid that lower the pH (3-5) and create an unfriendly environment for microbial growth

-line the respiratory, GI and genitourinary tracts

-can be penetrated by some microbes (ex. Treponema pallidum, herpesvirus)

-nose contains hairs that filter air

-the trachea is lined with cells covered in cilia that sweep dust and microorganisms up and out at 1 to 3 cm per hr

-smoking - tar builds up, cilia don't work

-urine & vaginal secreations wash away organisms that may enter there

-lysozyme - an antimicrobial enzyme found in sweat, mucous, & tears

-gastric juice in the stomach (HCl) - pH  1.2 - 3.0 kills most bacteria

-exception: Helicobacter pylori - neutralizes acid and causes 90% of stomach & peptic ulcers

-bacteria normally present can produce environmental conditions that prevent growth of pathogens

-ex. Lactobacillus acidopilus in the vagina lowers the pH and inhibits Candida albicans

-ex. E. coli in the intestines produces bacteriocides that inhibit the growth of Salmonella & Shigella

-neutrophils -function: phagocytosis

-eosinophils -function: make toxic proteins

-basophils -function: make histamine

-monocytes -function: phagocytosis when they become macrophages

-lymphocytes -NK, T, & B cells

-also known as polymorphonuclear leukocytes (PMN)

-also known as polys or neuts

-usually 60-70% of WBC

-function: phagocytosis

-have granules "granulocytes"

-increase with infection

-pus: dead white cells

-nucleus has lobes, tiny pink granules

-immature are called "bands"

-less mature called "metas" (meta myelocyte), may indicate losing battle

-increase with parasitic worm infections and allergic reactions

-2-4% of WBC

-function - make toxic proteins

-big red granules, bilobe nucleus

-involved in inflammation and allergic reaction

-0.5 - 1% of normal WBC

-granules contain histamine

-big blue granules with histamine

-agranular

-3-8% of normal WBC

-mature into macrophages in tissue fluid and become phagocytes

-diapedesis - leaving blood to go into interstitial fluid

-made in bone marrow

-big nucleus, takes up 70% of cell

-3 types (NK, T, B)

-20-25% of normal WBC

-smaller than monocyte, very little cytoplasm, dense dark blue nucleus, no granules

-increase with viral infections

-become "downy" with disease mononucleosis, Epstein-Barr virus bubby cytoplasm

-vasodilation

-increase blood flow to allow influx of WBCs, platelets and clotting factors

-clotting factors form fibrin

-histamine

-kinins

-prostaglandins

-leukotrienes

-redness

-swelling

-heat

-pain

-sometimes loss of function

-acute - intense and short lived

-chronic - less intense, longer, more destructive

-controlled by the hypothalmus

-blood-brain barrier, hypothalmus does not have

-pyrogen - a chemical that resets the hypothalmus to a higher temperature

-cryogen - a chemical that resets the hypothalmus to a lower temperature

-when Gram neg. bacteria are phagocytized they release cytokines that reset the hypothalamus to a higher temperature

-higher temperature setting causes: shivering, increased metabolic rate, constriction of blood vessels

-when the cytokines are eliminated or cryogens are produced, the thermostat is reset to 37°C, causes: vasodilation, sweating

-when bacteria are in an abscess, they come out into the blood & you will "spike a temp" for a short time, this is when you draw blood cultures

-complement consists of over 30 proteins

-made in the liver

-circulate in the blood and are in tissues

-complements the immune system in destroying microbes

-part of the innate immune system but is initiated by the adaptive immune system

-proteins interact in a cascade fashion where one protein activates the next in the chain

function: Cytolysis, Inflammation, Enhance phagocytosis

-proteins are numbered C1 - C9

-activated fragments are labeled with lower case a & b, ex. C3a and C3b

-C3 is the protein that begins the complement cascade that results in cytolysis, inflammation, & enhanced phagocytosis

-C3 splits into C3a and C3b

-C3b has 2 actions: binds to the surface of microbes and attracts phagocytes (opsonization), also splits C5 into C5a and C5b

-C5b binds with C6, C7, and C8 and insert themselves into the cell membrane of a microbe. This attracts many C9's. C9 molecules insert themselves into the cell membrane and form a "membrane attack complex" (MAC) or pore

[image]

-This causes fluid to rush in and the cell lyses!

-C3a and C5a bind to mast cells causing them to release histamine which increases the permeability of blood vessels. C5a also attracts phagocytes

*Gram neg bacteria have only 1 layer of peptidoglycan and are more susceptible to complement

-antibodies bind to antigens of the membrane of an invading microbe

-C1 binds to this antigen-antibody complex

-C1 activates both C2 and C4

-C2a and C4b combine and activate C3

http://www.youtube.com/watch?v=y2ep6j5kHUc

-does not involve antibodies

-C3, present in the blood, combines with complement proteins on the surface of an invading microbe. These proteins are called: Factor B, Factor D, Factor P (properdin)

-C3 is then activated, splits, and begins the complement cascade

-after a macrophage ingests a bacteria or virus it releases cytokines

-cytokines stimulate the liver to make lectins

-one lectin called mannose-binding-lectin (MBL) binds to mannose, a sugar found in the membranes of bacterial cell walls and on some viruses

-MBL activates C2 and C4

-C2a and C4b combine and activate C3

-regulatory proteins on the host's blood and on blood cells act as inhibitors of excess complement activity by breaking down activated complement

ex. Regulatory protein CD59 prevents assembly of C9 so MAC cannot form

-an inherited deficiency of one or more complement's proteins can result in increased susceptibility to disease

-complement has been implicated in worsening autoimmune disorders, ex. Lupus erythematosus, MS, rheumatoid arthritis, inflammatory bowel disease

-some capsules contain sialic acid which inhibits MAC formation

-some gram positive bacteria release an enzyme that breaks down C5a so phagocytes are not attracted to the area

-proteins made by virus-infected cells

-diffuse to nearby uninfected cells and cause them to make anti-viral proteins, which protect them

-they are effective against more than 1 virus

approved in the US for treating:

-Kaposi's sarcoma

-Herpes

-Hepatitis

-Melanoma

-Crohn's disease

-Rheumatoid arthritis

-Hairy cell leukemia

-short chains of amino acids that destroy bacteria by:

-inhibiting cell wall synthesis

-forming holes in their plasma membrane

-destroying bacterial DNA and RNA

ex. Dermacidin made by sweat glands

ex. Defensins mabe by neutrophils

Helicobacter pylori
Lactobacillus acidophilus

toxins of Clostridium botulinum & Staphylococcus aureus

-to destroy the injurious agent, if possible, and to remove it and its by-products from the body

-if destruction is not possible, to limit the effects on the body by confining or walling off the injurious agent and its by-products

-to repair or replace tissue damaged by the injurious agent or its by-products

tonsils, thymus, lymphatic vessel, large intestine, red bone marrow, heart, thoracic duct, spleen, small intestine, Peyer's patch, lymph node

[image]

an increase in the number of WBCs

may be caused by meningitis, infectious mononucleosis, appendicitis, pneumococcal pneumonia, gonorrhea

a decrease in number of WBCs

may be caused by salmonellosis, brucellosis, some viral infections, some ricksettial infection

-adaptive immuinity is induced

-you are exposed to a foreign invader

-produce antibodies & recover

-you are immune to future infections

(antibody generator)

foreign or "non-self"

thymus - in chest - large in kids, small in adults

Bursa of Fabricus - in birds - similar

Remove BoF from mature bird

No health effect

Inject with Salmonella

Produce antibodies to Salmonella

Remove BoF from young chick

No health effect

Inject with Salmonella when adult

Do not produce antibodies

Some got sick & died

Bursa of Fabricus is needed for the maturatoin of the immune system

-2 cells are needed to complete antibody production

*1st cell recognizes antigen as foreign

*2nd cell makes antibody

proteins or large polysaccharides

usually parts of:

cells walls

capsules

flagella

fimbrae

bacterial toxins

viral coats

Also:

-surface of RBCs & WBCs

-pollen

-proteins from other people or species

-egg white

-surface molecules on transplanted tissue & organs

specific region of an antigen that antibodies are directed against

[image]

-most antigens weigh >10,000 Daltons

-if they are smaller, they are called a hapten

-the hapten can attach to a carrier molecule

-antibodies are produced when the hapten-carrier compound is present

[image]

-once produced, those antibodies will react with the hapten alone

compact proteins that:

-are made by plasma cells in response to an antigen

-attach to antigens & sometimes complement

-are also called immunoglobulins

-have 2 identical binding sites, that bind to epitopes

-have 2 light & 2 heavy chains

[image]

-monomer

-80% of serum Abs

-fix complement

-in blood, lymph, and intestine

-Cross placenta - passive immunity

-Enhance phagocytosis, neutralize toxins and viruses

-pentamer

-5-10% of serum Abs

-fix complement

-in blood, in lymph, and on B cells

-agglutinates microbes!

-first Ab produced in response to infection

[image]

-dimer

-10-15% of serum Abs

-in secretions: tears, saliva, mucus & breast milk

-protects infants from GI infections

[image]

-monomers

-0.2% of serum Abs

-in blood, in lymph, and on B cells

-aka reagin

-0.0002% of serum Abs

-involved in allergies, parasitic infections, & syphilis

-bind to mast cells & basophils

-antigens attach to the binding sites

-cells release histamine & attract phagocytes

-Rapid Plasma Reagin (RPR) is the test for syphilis

-T and B lymphocytes develop from stem cells in red bone marrow

-Humoral immunity - activated B lymphocytes make antibodies, mature in the bone marrow

-Cellular immunity - due to T lymphocytes, T cells mature in the thymus

-carry immunoglobulins on their surface

-the immunoglobulins bond to the epitopes for which they become specific

-an activated B cell differentiates into a plasma cell that makes antibodies or a memory cell

*T-independent antigens

*T-dependent antigens

B cells contacts antigen & becomes activated

[image]

-once the B cell is activated, clonal selection occurs

-the B lymphocytes become either:

-a memory cell - a long lived cell that will become an antibody-producing cell if the same antigen is encountered later

-or an antibody-producing plasma cell

-clonal deletion elminates harmful B cells (B cells that attack self)

-memory cells speed up immune response

-B cell with "undifferentiated" (does not destroy antigents) antibodies already on its surface, binds to an epitope, processes it, and displays the antigen and the MHC on its surface (APC)

-T helper (T_H) cell binds to the B cell-antigen complex and releases cytokines (if foreign)

-B cell is activated by cytokines & proliferates

-then clonal selection occurs (some progeny become antibody-producing plasma cells, some become memory cells)

(antibodies made by plasma cells)

-agglutination

-opsonization

-complement fixation

-antibody-dependent cell-mediated immunity

-neutralization

Antigens stick to each other

Reduces number of infectious units to be dealt with

Agglutination also happens to RBCs

[image]

-coating antigen with antibody enhances phagocytosis

[image]

-causes inflammation and cell lysis

-this also happens to RBCs

[image]

-involves large antigens like parasites!

-antibodies attach to target cell, cause destruction by macrophages, eosinophils, and NK cells

-cytotoxicity

[image]

-blocks adhesion of bacteria and viruses to mucosa

-blocks attachment of toxin

[image]

-Affinity - the strength of the bond between an antigen and antibody

-Specificity - antibodies are very specific in their target, if there is a slight difference in the amino acid sequence of a protein, they will not bond

-T cells mature in the thymus

-We make fewer T cells as we age

-This results in a lowered immunity in the elderly

-they differ in their cell membrane glycoproteins, which are called "clusters of differentiation" or CD

-T cells require antigen-presenting cells (APCs)

-T Helper (T_H) or CD4⁺ cells use glycoproteins on their surface to adhere to receptors on an antigen presenting cell

-Activate B cells to make antibodies

-Activate macrophages

-Activate eosinophils to release perforin and lytic enzymes to destroy parasites

-Form memory cells

-T Cytotoxic (T_C) or CD8⁺ cells become cytotoxic T lymphocytes (CTL) cells that identify and destroy cells that are non-self:

-virus infected cells

-tumor cells

-transplanted cells

-releases pore forming protein perforin

[image]

-T Regulatory (T_REG) cells a subset of the CD4⁺ T Helper cell population

-combat autoimmunity by supressing T cells that do not recognize the body's self

-protect against immune destruction of normal flora

-protect the fetus

-NK cells, 3rd type of lymphocyte

-Can directly destroy:

-viruses

-parasites

-tumor cells

-antibody titer is amount of antibodies in serum

-primary response occurs after initial contact with antigen

-secondary (memory or anamnestic) response occurs after second exposure

First contact with antigen...no antibodies

*4-7 days after exposure, IgM titer rises to a low level and falls by 16-18 days after exposure

*5-8 days after exposure, IgG titer rises slowly to a low level and falls by 3 weeks following exposure, but does not disappear

**the 2nd exposure to the same antigen causes a small temporary rise in IgM and...

***a rapid, large rise in IgG titer that stays elevate for many years and causes production of memory B cells

-active immunity - we make our own antibodies

-passive immunity - we are given antibodies that were made in another organism

-naturally acquired - we are infected with an antigen and make our own antibodies or we get antibodies from Mom through placenta or milk

-artifically acquired - we are injected with antigens or antibodies

-a suspension of organisms or fractions of organisms

-used to induce immunity without causing full-blown disease

-when most of the population is immune to a disease

-occasional cases occur

-there are no epidemics

http://www.health.harvard.edu/multimedia/herd-immunity-animation

-attenuated whole-agent vaccines

-inactivated whole-agent vaccines

-toxoids - inactivated toxins

-subunit vaccines

-conjugated vaccines

-nucleic acid vaccines

-microbes are attenuated (weakened) usually using heat

-95% effective

-ex. polio, measles, mumps, rubella, TB

-not recommended for the immunocompromised

-use microbes that have been killed with formalin or phenol

-less effective than attenuated vaccines

-ex. rabies, influenza, polio, rotavirus, pneumococcal pneumonia

-inactivated toxins

-require a series of vaccinations & booster shots

-ex. tetanus & diphtheria

-use only the antigenic fragment of a microorganism

-ex. hepatitis B & pertussis, DTaP vaccine

-an organism with an antigen that is a capsule polysaccharide is not antigenic in children under 24 mos.

-so polysaccharides are combined with proteins before being innoculated

[image]

-human applications are being worked on

-plasmids of DNA are injected into muscle

-the protein that the DNA codes for is produced

-the protein antigens migrate to the red bone marrow

-humoral & cellular immunity are induced

[image]

-an antigen can be injected into an animal who produes a large number of antibodies

-those antibodies can be collected and used in diagnostic testing

-they are not always pure and antibody titers may be low

-more recently it was discovered that cancerous B cells will live forever in cell culture!

(cells usually have telomeres which get shorter until they induce apoptosis - programmed cell death)

-if a cancerous B cell is fused with an antibody-producing B cell, huge amounts of pure "monoclonal antibodies" can be produced

(August 18, 1920 - October 4, 1951)

An African American woman who was the unwitting source of cells from her cancerous tumor, which were cultured by George Otto Gey to create an immortal cell line for medical research. This is now known as the HeLa cell line.

-precipitation reactions

-immunodiffusion tests

-agglutination

-neutralization

-complement fixation test

-fluorescent antibody techniques

-enzyme linked immunosorbent assay (ELISA)

-Western blotting

-antibodies bind to soluble antigens

-antigen-antibody complexes join to form large "lattices" that form precipitate

[image]

-percipitation reactions that are done in gel agar

[image]

-antibodies bond to particulate antigens to form a visible clump (ex. RBCs)

[image]

-antibodies that block bacterial exotoxins

[image]

-helps antibodies lyse cells

this test looks for antibodies

if there are no antibodies present in the serum, hemolysis of the sheep RBCs will occur.

(no cell lysis = positive result, hemolysis = negative result)

[image]

-tag antibodies with fluorescent dyes

-fast & accurate

-used to detect rabies

[image]

http://www.youtube.com/watch?v=RRbuz3VQ100

-proteins in a mixture are separated using electrophoresis

-they are then flooded with a colored label and compared to standards

-a confirmatory test for HIV

[image]

http://www.youtube.com/watch?v=5CMVqRdh0Yk

-there are many antibacterial drugs that kill prokaryotes

-this is because their cells are very different from ours

-we can kill them without harming ourselves because prokaryotes have:

-different enzymes

-different ribosomal structure

-some have cell walls

Antibiotic - an antimicrobial agent, usually produced naturally by a bacterium or fungus

-most are produced by the soil microbe Streptomyces

-some are made by the spore former Bacillus

-some come from the molds Penicillium and Cephalosporium

-Narrow spectrum-only kill a few types of bacteria-ex Penicillin G kills many gram positive organisms, but few gram negatives

-Broad spectrum-kill many types of bacteria, can kill off normal flora and set the stage for an opportunist

-fungi, protozoans, helminths

-they are harder to kill without damaging their host because their cells are more similar to ours

They are either:

-Bactericidal - kill bacteria

-Bacteriostatic - stop bacteria growth

-cell wall inhibition

-antimycobacterial drugs

-protein synthesis inhibition

-nucleic acid inhibitors

-competitive inhibitors of essential metabolites

-antifungal drugs

-antiviral drugs

-antiprotozoan drugs

-antihelminthic drugs

-stops production of peptidoglycan so the cells cannot divide but become large and lyse

-gram positive organisms only, will not kill gram negative

-penicillins*

-carbapenems*

-cephalosporins*

-polypeptide antibiotics

-vancomycin* -use to treat MRSA -!Vancomycin reisistant enterococci are considered a medical emergency

-bacitracin - topical

Resistance to penicillins:

-Penicillin contains a β-lactam ring

-Some organisms produce β-lactamase

-We combine potassium clavulanate with penicillin. It is a noncompetitive inhibitor of penicillinase

-This combination is used in Augmentin

Methacillin Resistance - (a synthetic penicillin) some staph are resistant - MRSA

-Mycobacterium have unique cell walls which contain mycolic acids

-M. tuberculosis lives inside macrophages or walls itself off in tissue forming a "tubercle". Therefore drugs used to treat TB must be able to penetrate these areas

-The drug isoniazid* (INH) inhibits mycolic acid synthesis. It is used in combination with other drugs like rifampin* or ethambutol*

-doesn't kill, makes TB go into hiding

-sensitive to UV radiation

-M. tuberculosis and M. leprae are notifiable infections

-Almost 1/3 of the Earth's population is infected with TB

-all drugs of this type interact with bacterial ribosomes which are structurally different from our ribosomes

-Bacterial ribosomes are 70S. They are made of a 50S & a 30S sub-unit. Our ribosomes are 80S.

-chloramphenicol* - binds to 50S sub-unit and inhibits formation of peptide bonds (rarely cause aplastic anemia - bone marrow fills in with fibrous material) - antibiotic of last resort

-aminoglycosides - change the shape of the 30S portion causing the code on mRNA to be read incorrectly. ex. streptomycin*, Neomycin, gentamicin* - kills Pseudomonas

-tetracyclines - bind to the 30S sub-unit and prevent attachment of tRNA to mRNA. !Tetracyclines have the broadest spectrum of activity

-inhibit mRNA production

-rifampin* used to treat TB and leprosy - turns secretions red/orange

-stop production of protein, DNA or RNA

-the sulfa drug trimethoprim/sulfamethoxazole* (TMP-SMZ)

-two drugs which are synergists (work together) so we can administer a much lower dose of the combination than if each was used alone

-inhibit sterol production in the cell membrane

-humans have cholesterol in cell membrane

-fungi have ergosterol

-Amphotericin B* - toxic to the kidneys

-Nystatin* - used topically to treat Candida albicans

-inhibit DNA or RNA synthesis

-Interferons* - inhibit spread of viruses to new cells

Chloroquine* - an antimalarial

Metronidazole* (Flagyl) - for giardia and trichomonas

-kill worms

-Ivermectin*

-produced by Streptomyces avermectinius

-used to treat: roundworms, mites, ticks, and headlice

-disk-diffusion method (Kirby-Bauer test, E test)

-broth dilution test

-disk diffusion method

-based on the principal that the concentration of antibiotic decreases as distance from the disc increases

[image]

-a lawn of bacteria is created on a plate

-strips with an increasing gradient of antibiotic are placed on the lawn

-the plate is incubated

-the MIC can be determined from the scale on the strip

[image]

-used to determine the minimal inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC)

-the drugs are serially diluted in a broth and placed in the wells of a plastic tray

-a suspension of an isolated organism is innoculated into the broths

-the tray is incubated

-the MIC is the lowest dilution with no growth

[image]

[image]

-Bacteria produce enzymes that destroy antibiotics. ex - penicillinase

-Prevention of Penetration - Gram negative organisms are harder to kill than gram positives because their cell walls restrict entry of antibiotics

-Alteration of the drug's target site - bacteria can alter their ribosomes to resist antibiotics that target protein synthesis

-Efflux of the antibiotic - gram negative bacteria have protein pumps in their cell membranes that can remove antibiotics from the cell as soon as they enter

Allergic Reactions

-Mild allergic reactions consist of an itcy rash or slight wheezing

-Severe allergic reactions (anaphylaxis) can be life-threatening and usually include swelling of the throat, inability to breathe, and low blood pressure

Side Effects

-common side effects of antibiotics include: upset stomach, diarrhea, and vaginal yeast infections

-some antibiotics may impair the function of kidneys, liver, bone marrow, or other organs

-Clostridium difficile produces a type of colitis, results from a toxin produced by the bacteria

Antibiotic specific side effects

Aminoglycosides (Gentamicin) - hearing loss

Carbapenems (Imipenem) - seizures

Fluoroquinolones (Ciprofloxacin) - rupture of tendons, abnormal heart rhythms

Macrolides (Zithromax) - jaundice, abnormal heart rhythms

Sulfonamides (Sulfamethazone) - Decrease in WBC and platelet count

Chloramphenicol - Severe decrease in WBC count, aplastic anemia

Metronidazole (Flagyl) - peripheral neuropathy

Vancomycin - decrease in WBC and platelet counts