Lecture 5-7 Flashcards
What is innate immunity?
The relatively non-specific ability to phagocytize foreign organisms, particles, some cancerous cells and exhausted/worn out cells such as old RBC’s
What is adaptive immunity?
A specific response is generated principally by the production of antibodies and so-called “memory” cells which “remember” the antigen and are therefore able to mount a far quicker and more effective response with subsequent exposure.
Name the 3 granulocytes.
Neutrophils, Eosinophils, Basophils
Name the 2 agranulocytes.
Lymphocytes, Monocytes
What is the function of neutrophils?
Destroy bacteria by phagocytosis
D: 6-9 days
LS: 6 hrs to a few days
3000-7000 per mm^3
What is the function of Eosinophils?
Turn off allergic responses and kill parasites
D: 6-9 days
LS: 8-12 days
100-400 per mm^3
What is the function of basophils?
Release histamine and other mediators of inflammation
D: 3-7 days
LS: ? few hrs to few days
20-50 per mm^3
What is the function of lymphocytes?
Mount immune response by direct cell attack (t-cells) or via antibodies (B-cells)
D: days to weeks
LS: hrs to years
1500-3000 per mm^3
What is the function of monocytes?
Phagocytosis: develop into macrophages in tissues
D: 2-3 days
LS: Months
______ and _____ cells release histamine and other chemicals involved in inflammation.
Basophils; Mast
How does leukocytes move around the body?
Via the blood and lymph
Granulocytes and monocytes seeks out invading organisms by means of ___________
chemotaxis
Which leukocytes has the most abundance in the blood?
Never: Neutrophils (62%) Let : Lymphocytes (30%) Monkeys: Monocytes (5.3%) Eat: Eosinophils (2.3%) Bananas: Basophils (0.4%)
T or F? Granulocytes has intracellular granules and have multilobed nuclei.
True
What are natural killer (NK) cells?
A class of lymphocytes that bind to cells bearing foreign antigens without specific recognition and kill them directly; major targets are virus-infected cells and cancer cells; participate in antibody-dependent cellular cytotoxicity (ADCC)
T or F? Granulocytes and lymphocytes protect primarily by phagocytosis, (innate)
False, Granulocytes and granule-free monocytes not lymphocytes.
What type of stem cells are WBC’s derived from?
pluripotent hematopoietic stem cells (from there, they could become myeloblasts or lymphoblasts)
___ ______ _____, typically released with by macrophages at the site of infection, trigger the production of the appropriate WBC’s in the bone marrow.
Colony-stimulating factor
T or F? The majority of WBC’s are circulating within the blood.
False, ~6 days worth of WBC’s are stored in bone marrow or lymphoid tissue.
What is the typical lifespan of granulocytes?
`4-8hrs in the blood plus ~5-6 days in the tissues where needed (could be reduced when fighting infections)
T or F? Monocytes spend about ~10-20hrs in the blood before entering tissues where they enlarge and mature into active tissue macrophages which can survive for months.
True
Lymphocytes enters the blood via the ________.
Lymph, where they circulate only to invade tissues and subsequently re-enter the lymph
Immune cells can pass through “gaps” in the capillary endothelium to enter the tissues by a process called _______.
Diapedesis
What are released by damaged cells at the site of infection to attract appropriate immune cells?
Chemokines
_____ are primarily found in the blood while ___ move into the tissues. (However, when tissue damage and inflammation occur many substances are released which attract these cells by chemotaxis)
Neutrophils ; macrophages
What are the 2 innate mechanisms that attracts phagocytes to pathogens?
- Many pathogens have roughened surfaces, our cells are smooth.
- Most pathogens lack the repellant protective coats that our cells possess.
What is the so called alternate complement pathway?
A complement system that can be activated without the involvement of antibodies during inflammation.
Complement system factor ____ binds to cell surface/cell wall carbohydrates of bacteria which allows more effective phagocytosis. (opsonization)
C3b
Which phagocytes projects pseudopodia around a pathogen to engulf it to be phagocytized?
Neutrophils and macrophages
T or F? Neutrophils can ingest worn out RBC’s and even malaria parasites.
False, macrophages not neutrophils
Macrophages releases ______ (neutrophils does not release this) which can attack the thickened membranes which some bacteria possess.
lipases
What is the membrane attack complex?
A group of complement proteins that form channels in the surface of microbe, making it leaky and killing it.
What are the most potent arsenal of phagocytes?
Oxidizing agents; Superoxide (O2), Hydrogen peroxide (H2O2), and hydroxyl ions (OH-)
The lysosomal enzyme myeloperoxidase catalyzes the reaction between H2O2 and Cl to form _______.
Hypoclorite (bleach); extremely bactericidal. (tuberculosis bacillus is resistant)
Local inflammation of subcutaneous tissue triggers local tissue macrophages called _________
dendritic cells or histiocytes
What happens to invading organisms that are not phagocytized by local tissue macrophages?
They are removed via the lymph as it cannot cross the endothelium and enter the blood.
Lymph circulates through the lymph nodes where bacteria tend to become trapped by the__________ _______ , (from fibroblasts), and then phagocytized by macrophages that line the lymph nodes or destroyed by various antibody/complement/etc. mechanisms.
reticular meshwork
What happens to inhaled organisms or particles that are not digestible by macrophages that are in the alveolar walls of the lungs?
Sometimes a giant cell capsule is formed around them so hopefully isolating and inactivating them: capsules are typically formed around tuberculosis bacilli which are difficult to kill plus silica and carbon particles.
What is the name of the macrophage that line the sinusoids between the hepatocytes through the hepatic portal vein?
Kupffer cells. These macrophages are therefore perfectly positioned to filter out foreign cells and material entering from the GI tract.
If an invading organism, etc. does manage to enter the blood despite the previously mentioned defenses they can be removed as the blood passes through the ____ _____ of the spleen and bone marrow by macrophages
reticular systems
Where does old or abnormal RBC’s go to be recycled?
Spleen
When tissue damage occurs, what important substances are released?
These include histamine, bradykinin, serotonin, (modulator), prostaglandins, complement system factors, factors involved in blood clotting, (especially Tissue factor/factor III), and lymphokines from lymphocytes .
What is characterized by local vasodilation which increase blood flow and together with increase capillary permeability allows the leakage of plasma proteins, granulocytes and monocytes, (immature macrophages), attracted by chemotaxis into the ECF of the affected tissue.
Inflammation
T or F? Leakage of clotting factors, including fibrinogen, into the ECF allows it to clot so helping limit the spread of any pathogens or toxins.
True
T or F? Very shortly after inflammation begins, macrophages already present in the tissues enlarge and begin phagocytosis.
True, this activation can cause previously attached macrophages to release and become the first response, (<1 hour), which is extremely important
The second response, after ~1 hour increase number of ______ invade the inflamed tissues from the blood.
neutrophils
What is margination?
Certain adhesion molecules that initially loosely tether neutrophils to the endothelial surface near the site of infection (just before diapedesis)
What is neutraphilia?
A release of stored neutrophils from the bone marrow and can result in x4 increase in circulating neutrophils.
What is the 3rd response?
Immature monocytes enter the affected tissue and become functional macrophages, (~ 8 hours), but their numbers are low initially: a full response requires several days
What is the final response of innate response?
A large increase in production of both granulocytes and monocytes occurs in the bone marrow. (Constant increase if inflammation persists)
More than 24 substances have been implicated in the response to inflammation, 5 in particular that are released by activated macrophages are thought to be of prime importance. What are they?
- Tumor necrosis factor (TNF)
- Interleukin-1 (IL-1)
- Granulocyte-monocyte Colony-stimulating Factor, (GM-CSF
- Granulocyte Colony-stimulating Factor, (G-CSF)
- Monocyte Colony-stimulating Factor, (M-CSF)
What are interferons and where do they originate?
Interferons are a family of cytokines that nonspecifically inhibit viral replication inside host cells: when most cell types are infected they secrete interferons.
T or F? Interferons act in an auto- and paracrine manner causing the synthesis of literally dozens of antiviral proteins in both infected and uninfected cells.
True
As neutrophils and macrophages phagocytize bacteria and necrotic tissue they wear out and die: after several days a cavity is formed which fills with these dead cells, tissue and tissue fluid and is called ______
Pus
Pus eventually ________ and is re-absorbed.
autolyzes
__________ are produced in greater response to parasitic infections when they are attracted by chemotaxis and release substances toxic to most parasites
Eosinophils
What does eosinophils release that are toxic to most parasites?
Hydrolytic enzymes
Certain ROS’s
Major Basic Protein (highly larvacidal polypeptide)
The primary cells involved in allergic responses are _____ and _____, these release an Eosinophil Chemotactic Factor which attracts eosinophils which may then detoxify certain substances involved in inflammation.
Mast cells ; basophils
What does basophils and tissue mast cells release in response to inhibit coagulation?
Heparin, histamine and small quantities of bradykinin and serotonin
Basophils and Mastcells bind to a particular type of _____ that is produced under allergic conditions.
Antibody (IgE)
IgE antibodies attach to antigens triggering the release of increase amounts of _____, _____, ______, ______, _____ and ________ which causes local vasodilation and tissue reactions characteristic of allergic responses.
histamine bradykinin serotonin heparin slow-reacting Substance of Anaphylaxis Lysosymal enzymes
______ is a clinical condition the bone marrow starts to produce very low amounts of WBC’s: after ~ 2 days, (previously circulating/not stored WBC’s now dying), various infections start to occur and if not treated death can ensue <1 week!
Leukopenia
What are the primary cause of leukopenia?
Damage to the bone marrow as caused by exposure to gamma or x-rays, chemicals, certain drugs and barbiturates.
What is Leukemia?
Cancerous mutations of WBC precursor cells may result in uncontrolled production of WBC’s
_______ leukemia originates in the bone marrow and subsequently spreads throughout the body especially to lymph nodes, spleen and liver: cells are often undifferentiated with bizarre shapes
Myelogenous; The more undifferentiated the cells are the less function they have and in acute cases death can result in a few months if untreated
_______ leukemia usually develops in lymph nodes or other lymphoid tissues but spreads and develops in a similar fashion to myelogenous
Lymphocytic
The primary result of leukemia is the production of more non-functional/partially functional WBC’s in inappropriate areas of the body resulting in ________, ________
infection, severe anemia, and a tendency to bleed due to thrombocytopenia,
T or F? Leukemia, the most significant effect on the patient is often due to the very high metabolic demand placed on the body by these rapidly dividing cells: other tissues can be starved and forced to rely on protein catabolism.
True
What are the potential routes for invading pathogens?
Compromised skin (“dry” membrane), exposed mucus membranes (“wet” membrane), GI and respiratory tracts (and ears).
Many of our external bodily secretions contain which bactericidal enzyme?
Lysozymes
What reflex ejects foreign or potentially toxic material from the airways?
Coughing
What reflex ejects foreign or potentially toxic material from the nasal passages?
Sneezing
What chemical(s) present in the stomach killing virtually all potential pathogens ingested?
Stomach acid and pepsin
What are the potential routes for invading pathogens?
compromised skin (“dry” membrane), exposed mucus membranes (“wet” membrane), GI and respiratory tracts (and ears!!!!).
Many of our external bodily secretions contain which bactericidal enzyme?
lysozyme
What reflex ejects foreign or potentially toxic material from the airways?
coughing.
What reflex ejects foreign or potentially toxic material from the nasal passages?
sneezing.
What chemical/s present in the stomach kill virtually all potential pathogens ingested?
HCl and pepsin
- What are our physical barriers to infection?
integrity of the skin, secretions (sweat, tears, moist membranes), ear and nose hairs, stomach environment and “wandering” immune cells plus coughing, sneezing, vomiting and diarrhea.
- What is innate immunity?
the standard non-specific response to infection; primarily non-specific phagocytosis and inflammation.
- What is adaptive/acquired immunity?
a far more potent response to a specific antigen; improves with repeated exposure (immunization!).
