Susceptibility
Vulnerability or lack of immunity
Innate immunity
Non specific
Defenses that are present at birth.
Provide rapid responses to disease.
Does not involve specific recognition of microbes, and acts against all microbes in the same way.
Does not have memory component
Consists of first and second line of defe
Adaptive immunity
Specific
Defenses that involved specific recognition of a microbiology once it has breached the innate immunity defenses.
Based on specific responses to specific microbes
Changes and adapts
Slower to respond
Has a memory component
Involves lymphocytes T a
Toll like receptors
Protein receptors on plamsma membranes of defensive cells of INNATE IMMUNITY
detects LPS, flagellin, peptidoglycan, bacterial nucleotide sequences.
Present in macrophages and dendritic cells.
Release cytokines to regulate intensity and duration of immune
Cytokines
Relesed by Defensive cells stimulated by TLRs,
Recruit macrophages and dendritic cells to isolate and destroy microbes as part of inflammatory response.
Activate T and B cells
Induce fever like symptoms.
Leukocytosis
an abnormal increase in the number of white blood cells in the blood as a result of infection (as in leukemia)
Leukopenia
an abnormal lowering of the white blood cell count
Differential white blood cell count
Calculation of the percentage of each kind of white blood cell in a sample of 100 white blood cells.
Granulocytes
a group of leukocytes containing granules in their cytoplasm, neutrophils, eosinophils, basophils
Neutrophils
The most abundant type of white blood cell.
Stain lilac
Neutrophils are phagocytic and tend to self-destruct as they destroy foreign invaders, limiting their life span to a few days.
Have the ability to leave the blood and enter tissue to fight infection
Basophils
Stain blue-purple
Blood cells that enter damaged tissues and enhance the inflammation process and contain histamine and heparin
Eosinophils
Stain red
white blood cell that are responsible for combating infection by parasites by product of toxic proteins. Often too small to phagocytize larger parasites, bu can attach and relese peroxide ions into the parasite destroying them.
Somewhat phagocyt
Dendritic cells
Classified with granulocytes
Have long extensions similar to dendrites of nerve cells.
Abundant in skin, mucous membrane, thymus, and lymph nodes
Destroy microbes by phagocytosis and initiate addaptive immune response.
Agranulocytes
Have granules that are not visible under light Microscope after staining
Monocytes
an agranular leukocyte that is able to migrate into tissues and transform into a macrophage
Macrophages
Found within the lymph nodes, not phagocytic until they leave the blood , enter tissue and mature into macrophages
Maturation of macrophages is one cause of the swelling of lymph nodes during infection
Also dispose of worn out blood cells.
Lymphocytes
Natural killer cells
T and B cells
Fund in spleen, lymph nodes, and red bone marrow.
Kill a wide variety of cells which produce an unusual plasma membrane by secreting perforin to Lyse cell, or granzymes to digest the proteins of the membrane of the infec
Perforin
one of the proteins released by cytotoxic T cells on contact with their target cells. It forms pores in the target cell membrane that contribute to cell killing.
Granzymes
a protein-degrading enzyme secreted by the bound NK cell which enters the pore made by the perforins. Inside the enemy cell, the granzymes destroy cellular enzymes and induce apoptosis (programmed cell death).
Microbes from inside the cell are released an
T cells B cells
Not phagocytic, but play a key role in adaptive immunity.
Occur in blood, lymphoid tissue, in tonsils, spleen, thymus, thoracic duct, red bone marrow, appendix, small intestine, gastrointestinal and reproductive tract.
Phagocytosis
process in which phagocytes engulf and digest microorganisms and cellular debris
Part of second line of defense.
Phagocytes
Types of derivatives of white blood cells.
Activated by components of bacteria such as lipid A, or lipopolysacharides.
Mostly activated by cytokins secreted by other phagocytes.
Fixed macrophages
stationary phagocytic cell found in the liver, lungs, brain, spleen, lymph nodes, subcutaneous tissue, and red bone marrow. AKA histiocyte
Wandering macrophages
phagocytic cell that develops from a monocyte, leaves the blood, and migrates to infected tissues
Mononuclear phagocytic system
a system of phagocytic components which recognize, capture and remove foreign material from the body.
Fist stage of infection granulocytes are most prevalen.
Next macrophages become dominant and scavenge for remining bacteria and debri.
During viral or fu
Chemotaxis
Chemical attractions of phagocytes to microorganisms.
Microbial products
Components of whiteblood cells,
Damaged tissue cells,
Peptides derived from compliment.
Adherence
Attachment of plasma membrane of phagocyte to the surface of microorganism rotter foreign material.
Microorganisms can be more readily phagocytized if coated with serum proteins to promote binding.
Opsonins.
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
Opsonins
Proteins which attach to microbes to increase the ability of phagocytes to adhere
Ingestion
Following adherence, plasma membrane of phagocyte extends pseudopods that engulf microbe.
Once fully engulfed pseudopods fuse and form a phagosome.
The wall of the phagosome pumps protons (H+) into the microbe to lower pH so hydrolytic enzymes can be acti
Digestion
Phagosome pinches off and enters cytoplasm where digestive enzymes of lysosomes contact.
Phagosome and lysosomes form single phagolysosome killing bacteria in only 10-30 minutes.
Lysozyme, lipases, professes, ribonucleases, deoxyribonucleses, superoxide r
Inflammation
Response to cell damage:
Microbial
Heat, radiant, energy, electricity, sharp objects.
Acids, bases, gases.
Characterized by redness, pain, het, and swelling and occasionally loss of function depending on the site of infection.
Used to destroy and remove i
Acute phase proteins
Type of protein which Is activted and increases in concentration during inflammation.
Some are produced in the liver, others are inactive in the blood and activated during inflammation.
Induce both systemic responses and include compliment, cytokins, and
Vasodilation
Immediately following tissue damage, first stage of inflammation.
widening of the blood vessels that allows for increased blood flow,
Reason for redness and het
Edema
swelling from excessive accumulation of serous fluid in tissue, caused by increase in permeability during inflammation.
May cause pain associated with inflammation.
Histamine
chemical alarm signal released by damaged cells that causes blood vessels to dilate during an inflammatory response.
Especially present in mast cells of connective tissue., basophils, and blood platelets.
Also released by components of complement system,a
Kinins
involved in nonspecific inflammatory response its a chemical that increase vascular permeability, which leads to edema and swelling, attract neutrophils
Prostaglandins
Substances released by damaged cells.
Intensify effects of histamine and kinins.
Help phagocytes move through capillary walls.
Leukotrienes
Produced by mast cells and basophils.
Cause increased permeability of blood vessels, and help attach phagocytes to pathogens.
Pus
Mixture of dead cells and body fluids in response to blood clot which prevents microbes or toxins from spreading.
Abscess
Focus of infection, boils, pustules, pimples.
Margination
Phagocytes stick to the inner surface of endothelium of blood vessels at site of inflammation.
Phagocytes then squeeze between endothelial cells and emigrate to damaged tissue
Occurs within an hour of infection as blood flow to area lessens.
Emigration
Movement of phagocytes from blood vessels to damaged tissue.
Resembles ameboid movement.
Takes as little as 2 minutes
Chemokines
Cytokins that are chemotactic for phagocytes and T cells.
Stimulate inflammation response and adaptive immune response.
This increase in neutrophils stimulates anincreqse in granulocytes from red bone marrow, monocytes follow and become wandering macropha
Tissue repair
Final stage of inflammation.
Tissues replace dead or damaged cells
Ability to repair depends on the type of tissue:
Skin has high capacity for generation.
Cardiac muscle has low capacity for repair.
A tissue is repaired when it's stroke or parenchyma prod
Stroma
Supporting connective tissue involved in tissue repair.
If stroma are more active than parenchyma than scare tissue can form.
Parenchyma
Functional part of tissue involved in tissue repair.
If parenchyma are more active than stromq q near perfect repair can take place, like most cuts.
Fever
Inflammation is local, fever is systemic.
The most frequent cause of fever is the toxins of bacteria, or viruses.
When phagocytes ingest gram negative bacteria, the lipopolysaccharides of the cell wall are released and the phagocytes ease the cytokines IN
Shivering
Bodys response to elevated temperature setting by the hypothalamus.
Followed by blood vessel constriction and increased rate of metabolism.
Sensation of chill and cold skin indicates an increase in body temperature.
Crisis
Stage of fever when the infection begins to subside.
Hat losing mechanisms go into effect, sweating, vasodilation.
Body temp is falling
Complement sysmtem
Defensive system consisting of 30 proteins produced by the liver and found circulating in lood serum and within body tissues.
Destroy microbe by: cytolysis, inflammation, phagocytosis, and prevent excessive damage to host tissues
Usually designated by an
C3
Starts a cascade that results in cytolysis, inflammation, and phagocytosis.
C3b binds to microbes and phagocytes attach to C3b, acting in opsonization, or immune adherence.
C3b splits C5
C3b and C5a bind to mast cells initiating the release of histamine t
Membrane attack complex
C5b binds to C6 and C7 which bind to plasma membrane of invading cells, C8 and many C9 molecules join in to form cylindershapewhich inserts into membrane.
MAC creates holes in membrane inducing cytolysis.
Host cells contain proteins which block MAC from b
Complement activation
Cascade of complement proteins activating during an infection.
Occurs in three pathways,
Classical
Alternative
Lectin
Classical pathway
Complement activation,
Initiates when antibodies bind to antigens.
Antigen-antibody complexes bind and activate C1.
C1 splits C2 and C4 activating them.
C2a and C4b combine and split C3 which initiate cytolysis, inflammation and opsonization.
Alternative pathway
Complement activation
Does not involve antibodies
Activated by contact between pathogen and specific complement proteins
Complement proteins factor B and factor D are attracted to microbial cell surface material. C3 binds to proteins and is split.
C3a fun
Lectin pathway
Complement activation
Most recently discovered.
When macrophages ingest material they release chemicals to stimulate liver to produce LECTINS, proteins that bind to carbohydrates.
Lectins bind to patterns of carbohydrates present in bacteria and viruses f
Lectins
Proteins produced in the liver which bind to carbohydrates of bacteria and viruses
Mannose binding lectin
Proteins produced in liver which bind to carbohydrate mannose present in bacteria and viruses, to activate complements C2 and C4.
Inactivation of complement
Destructive capabilities usually cease shortly after activation to minimize destruction of host cells.
Accomplished by proteins in blood and on cells.
Proteins breakdown activated complement and and function as inhibitors and destructive enzymes.
Complement and disease
Complement plays a role in causing disease as a result of inherited deficiencies.
Deficiencies if C1, C2, and C4 cause collagen vascular disorders that result in hypersensitivity.
Deficiencies in C3 are rare, but result in increased susceptibility to recu
Evading the complement system
Use of capsules by bacteria to evade the complement system.
Bacteria not killed by MAC are said to be serum resistant
Interferons
Antiviral proteins produced by lymphocytes and macrophages after viral stimulation.
Interfere with virus multiplication
Host cell specific, but not virus specific.
Act against many viruses.
Protect human cells, but little protection from viruses for other
Alpha and Beta interferons
Both produced by virus infected cells in small amounts.
Diffuse into neighboring cells
React with plasma or nuclear membrane receptors inducing uninfected cells to produce mRNA for synthesis of antiviral proteins
Problems with interferons
Not stable for long periods of time
When injected induce headache
High concentrations are toxic to the heart, liver, kidneys, and red bone marrow.
No effect on viral multiplication on cells already infected by virus
Gamma interferons
Produced by lymphocytes
Induces neutrophils and macrophages to kill bacteria by phagocytosis
Antiviral proteins
Enzymes that disrupt various stages of viral multiplication.
Either degrades viral mRNA, or inhibits protein synthesis.
Produced in uninfected cells by the presence of interferons alpha and gamma frm infected cells.
Recombinant interferons
Produced atificially in a lab using recombinant DNA technology.
Pure and abundant.
Transferrins
Ion binding proteins found in milk, saliva, and tears.
Inhibit bacteria growth by reducing the amount of available iron.
Iron is required for microbial growth and it suppresses chemotaxis and phagocytosis
Too much iron can increase the risk of infection
Antimicrobial peptides
Bind to microbial plasma membranes causing cell lysis.
Produced by mucous membrane cells and phagocytes
One of the most important elements of innate immunity.
First line if defense, physical factors
Epidermis,
mucous membrane,
Mucus,
Lacrimal apparatus,
Saliva,
Hairs,
Cilia,
Epiglottis,
Urine,
Vaginal secretions,
Defecation and vomiting
Mucous is not as effective a barrier as epidermis
First line of defense, chemical factors
Sebum
Protective acidic film over skin surface that inhibits microbial growth
Lysozyme
Antimicrobia substance in perspiration, tears, saliva, nasal secretions, and tissue fluid
Gastric juice
Destroys bacteria and most toxins in the stomach.
Gastric juice
Second line of defense broad components
Defensive cells
Phagocytes and nature killer cells
Inflammation
Fever
Antimicrobial substances
Complement system
Interferons
Transferring
Antimicrobial peptides.