Immune system Flashcards
What are the functions of Lymph
- Normally, filtration of fluid out of the capillaries is slightly greater than absorption of fluid into the capillaries.
- The excess filtered fluid is returned to the circulation via lymph.
- One-way flap valves permits interstitial fluid to enter, but not leave the lymph vessels.
Edema occurs when?
- Occurs when the volume of interstitial fluid exceeds the capacity of the lymphatics to return to its circulation
- Can be caused by excess filtration or blocked lymphatics
Blockage of lympatics can be due to?
- Cancer
- Surgery
- Infections
This bacteria can cause blockage of lympatics
Wuchereria bancrofti
Causes Filariasis or Elephantitis
The body immune system entails four deferent systems which are?
- Antibody mediated (humoral) immunity – consist of B lymphocytes
- Cell mediated immunity – consist of T lymphocytes
- Complement system
- Phagocytes
These lymphocytes make up humoral immunity
B lymphocytes
These lymphocytes make up cell mediated immunity
T lymphocytes
Humoral immunity
Antibody mediated immunity
Immune system is composed of which 2 types of cells
- White blood cells (leukocytes)
- Tissue cells derived from white blood cells
Immune cells work together by two ways
- By actually destroying invading bacteria or virus by phagocytosis
- By forming antibodies and sensitized lymphocytes which destroy or inactivate the invaders
Leukocytes are made up of 2 types of cells which are?
Granulocutes
Agranulocytes
Name 3 granulocytes
Basophiles, eosinophils, neutrophils
Name 2 agranulocytes
lymphocytes, monocytes
Mobile units of defense that seek out and destroy a foreign invader
Leukocytes
Normal leukocyte count
4,000 – 10,000/ mL
Acute inflammatory response cell “first responders”
Neutrophiils
mixture of dead neutrophils is
PUS
Normal Neutrophil count
40%-75% of WBCs
These cells contain granules with heparin , histamine and bradykinin
Basophils
Defend against worm infection e.g. pinworm
Eosinophils- 2%
Cells with Large kidney shaped nucleus that are differentiated into macrophages in tissues
Monocytes (5%)
Degranulation of mast cells leads to release of?
Release of histamine, bradykinin, heparin , Slow reacting substance of anaphylaxis (SRS-A)
These cells Involve in type I hypersensitivity
Mast cells
Neutrophils
- Acute inflammatory response cell “first responders”
- Phagocytic cells
- 40%-75% of WBCs
- Multilobed nucleus (polys)
- Contain lysosomes with hydrolytic enzymes and oxidases
- “PUS” is a mixture of dead neutrophils
Basophils- 0.5%
- Mediates allergic reaction
- Contain basophilic granules with heparin , histamine and bradykinin
- Release due to binding of IgE
Eosinophils- 2%
- Defense against worm infection e.g. pinworm
- Highly pagocytic for Ag-Ab complex
Monocytes (5%)
- Large kidney shaped nucleus
- Differentiated into macrophages in tissues
Mast cells
- Similar to basophils
- Mediates allergic reaction
- Degranulation =release of histamine, bradykinin, heparin , Slow reacting substance of anaphylaxis (SRS-A)
- Can bind IgE to membrane
- Involve in type I hypersensitivity
- Cromolyn sodium (Intal) prevents mast cell degranulation, given for exercise induce asthma
This drug prevents mast cell degranulation
Cromolyn sodium
an outward radial movement of leukocytes toward the capillary endothelium
Magination
movement of leukocytes out of the circulatory system and towards the site of tissue damage or infection.
Diapedesis
Slow movement of the leukocytes toward the site of infection
Ameboid motion
Atraction of leukocytes to the source of infection
Chemotaxis
Cell ingestion of bacteria, viruses, other foreign particles by powerful oxidizing agents
Phagocytosis
Name 5 actions of phagocytic cells in correct order
- Magination
- Diapedesis
- Ameeboid motion
- Chemotaxis
- Phagocytosis
The reticuloendothelial system is composed of which immune cells
Monocyte-Macrophages
Macrophages are derived from monocytes
Also called monocyte-macrophage system
Macrophages “Pac man” are present in?
- lymph nodes
- lungs
- liver (Kupffer cells)
- spleen
- bone marrow.
What are the three main functions of macrophages that provide first line defense
- Phagocytosis
- Antigen presentation
- Cytokines productions
Phagocytes ingest bacteria, viruses, other foreign particles by powerful oxidizing agents. Identify the oxidizing agents
- Superoxide (O2-)
- Hydrogen peroxide H2O2
- Hydroxyl OH-
- hypochlorite ClO-
TB becomes a chronic infection because?
bacteria have protective coat against macrophage oxidizing agents
Macrophage in spleen removes encapsulated bacteria namely _______, _________and ________, therefore, splenic dysfunction will lead to infection. These require Vaccination.
- s.pneumonia
- salmonella
- H.influenza
Describe antigen presentation as a role of macrophages
Invaders are ingested and broken down.
Fragments of antigen presented on surface of macrophages along with MHC.
These antigens are presented to CD4
Describe Cytokines productions as a role of macrophages
e.g. IL-1(activates T-helper cell) and TNF (tissue necrotic factor)
Patient’s who have spleenectomy or spleen dysfunction will require what vaccines
- Pneumococcal
- H. influenza
- Salonella (there is a vaccine for salmonella typhi/ typhoid)
Coating of bacteria with antibodies/ complement proteins to enhance phagocytosis
Opsonization
Fetus will receive these antibodies fro the mother IgG
Phagocytosis by macrophage is enhanced by?
- Opsonization by antibodies/CP
- Lack of protective coat on infected or cancer cells
- Rough surface of offending agent
Name all the labeled steps of phagocytosis
- Binding
- Engulfment
- Phagosome formation, acidification, proteolysis
- Lysosome fusion
- membrabe disruption
- Antigen presentation
X. MHC
Name 4 substances involed in inflamation
−Bradykinin
−Histamine
−Serotonin
−Lymphokines
Inflammation Events
- Vasodilation
- Increase capillary permeability
- Migration of granulocytes and monocytes
- Swelling of cells
- Substances involved (Bradykinin, Histamine, Serotonin, Lymphokines)
- “Walling off” of inflammation by fibrin clot −Prevent spread. E.g Staph=> localized infection
First line of defense
Tissue macrophages ; already present in tissues
Second line of defense
Neutrophil invasion
−Margination, diapedesis, chemotaxis
−Stimulation of bone marrow to release stored leukocytes, 4-5 hours
− increased count – neutrophilia
Third line of defense
Macrophage proliferation −Invasion by circulating monocytes
Fourth line of defense
Stimulation of granulocyte and monocyte production −Growth factors produced by tissue macrophages: TNF, IL-1
Describe the Cell-mediated Response to Inflammation
- Tissue macrophages −First line of defense ; already present in tissues
- Neutrophil invasion −Second line of defense; Margination, diapedesis, chemotaxis ; Stimulation of bone marrow to release stored leukocytes, 4-5 hours; Elevated count = neutrophilia
- Macrophage proliferation−Third line of defense; Invasion by circulating monocytes
- Stimulation of granulocyte and monocyte production −Fourth line of defense; Growth factors produced by tissue macrophages: TNF, IL-1
- Formation of pus −Composed of dead neutrophils, monocytes and tissue debries
Describe the control of bone marrow production of granulocytes and monocyte-macrophages in response to multiple growth factors released from activated macrophages in an inflamed tissue
- Activated microphage will release G-CSF, granulocyte colony-stimulating factor; GM-CSF, granulocyte-monocyte colony-stimulating factor; IL-1, interleukin-1; M-CSF, monocyte colony-stimulating factor; TNF, tumor necrosis factor which direcly stimulate the bone marrow to produce granulocytes, monocytes/macrophages
- TNF and IL-1 produced by macrophage will also stimulate endothelial cells to produce GM-CSF, G-CSF and M-CSF to stimulate the bone marrow
Innate (natural) immunity is genetically-encoded (built in) to recognize
- Common pathogenic features
- Against foreign substances
- Not acquired through contact with an antigen
- Non specific
Innate immunity includes?
- Neutrophils
- Macrophage
- Natural killer cells
- Complement proteins
- Gastric acid
- Skin
- Dendritic cells
- Inflammation
Only type of T lymphocyte (?) that plays an important role in natural immunity
Natural Killer (NK) Cell
Natural Killer (NK) Cell
- “Pit Bulls” of defense system (constant surveillance)
- Only type of T lymphocyte (?) that plays an important role in natural immunity
- Specialized killers of virus-infected cells- “enemy hideouts” and tumor cells by inserting perforins
- Induce apoptosis (program cell death) of virally infected cells and tumor cells
- They are active without prior exposure to virus. That’s why called “natural” killer
- They do not have to pass through thymus in order to mature
- Killing does NOT require recognition of MHC proteins
- Not specific to any virus
- Induce cells to undergo apoptosis (programmed cell death)
- IL-2 activated NK cells are being used for the treatment of certain cancers.
When an NK cell recognizes a cell as “non-self” it releases _____________
cytotoxic perforins (stab the pathogens) and granzymes
a substance that can induce an immune response when introduced into an healthy host and that can react with the antibody produced from that response
ANTIGEN
“Antibody generator”
Acquired (adaptive) immunity
- Occurs after exposure to bacteria, virus or toxins
- Specific
- Mediated by circulating antibodies and lymphoid cells (T and B cells)
- Can be active or passive
Active immunity
- Is resistance after contact with foreign antigen e.g. bacteria
- The host actively produces antibodies
- Long lasting protection (memory)
- Slow onset
- Examples: clinical or sub-clinical infection, immunization
Passive immunity
- Is resistance based on antibodies preformed in another host e.g. sheep, goats, dogs or horses
- Short life-span of antibody
- Prompt availability
- IgA in breast milk and IgG through placenta are examples of passive immunity
- Example: after exposure to Tetanus toxin , Botulinum toxin, HBV, Rabies, patients are given preformed antibodies.
After exposure to _______ paients are given preformed antibodies to be healed rapidly.
- Tetanus toxin
- Botulinum toxin
- HBV
- Rabies
Mnemonic To Be Healed Rapidly
IgA in breast milk and IgG through placenta are examples of?
passive immunity