Flashcards in Patho Exam 4 Deck (58):
What are the functions of the the complement cascade?
May destroy pathogens directly or collaborate with other components of the inflammatory response.
3 pathways of the complement cascade
1. Classical pathway
2. Lectin Pathway
3. Alternative pathway
How is the classical pathway activated
Activated by proteins of the adaptive immune system (antibodies) bound to their specific targets (antigen)
How is the lectin pathway activated
By mannose-containing bacterial carbohydrates
How is the alternative pathway activated?
By gram-negative bacterial and fungal wall polysaccharides
What is MBL
Mannose Binding Lectin which is similar to C1q
What are MASP-1 and MASP-2?
Mannose Binding Lectin (MBL) Associated Serine Proteases. Similar to C1r and C1s.
Effect of C2b
Acts on smooth muscle causing vasodilation and vascular permeability
What is the effect produced by C3a, C4a and C5a?
They are anaphylatoxins - they induce rapid mast cell degranulation and the release of histamine causing vasodilation and vascular permeability.
What is the major chemotactic factor for neutrophils?
What is a chemotactic factor?
A biochemical substance that attracts leukocytes to the site of inflammation.
Anaphylatoxins are early or late in the immune response?
Early and close to the inflammatory site to induce local mast cell degranulation.
Is chemotactic activity early or late in the inflammatory response?
Later on and remains for a much longer period than anaphylatoxins. It occurs distal and attracts leukocytes from the circulation and limits the spread of anaphylatoxin activity
What are the 3 plasma protein systems?
1. The complement system
2. The clotting system
3. The kinin system
What does carboxypeptidase do?
Removes a terminal arginine on C3a and C5a producing C3a desArg and C5a desArg. Both are inactive as anaphylatoxin a but remain active as chemotactic agents
What is an Opsonin?
Molecules that "tag" microorganisms for destruction by neutrophils and macrophages.
Which part of the complement system is an Opsonin?
What is the end result of the complement cascade?
What are the 4 functions of the clotting cascade?
1. Prevent the spread of infection to adjacent tissues
2. Trap microorganisms and foreign bodies at the inflammatory site for removal by neutrophils and macrophages
3. Form a clot to stop bleeding
4. Provide a framework for future repair and healing
What substances can activate the clotting cascade?
5. Bacterial endotoxins
What are the 2 pathways of the clotting system?
1. Tissue factor (extrinsic) pathway
2. Contact activation (intrinsic) pathway
What activated the tissue factor (extrinsic) pathway?
Activated by TF aka (thromboplastin) that is released by damaged endothelial cells in blood vessels and reacts with activated factor VII
What activated the contact activation (intrinsic) clotting pathway?
Activated when the vessel wall is damaged and Hageman factor (factor XII) in plasma contacts negatively charged subendorhelial substances.
Where do both clotting pathways converge?
On factor X which when activated begins a pathway leading to activation of fibrin to form a clot.
In what ways does bradykinin augment inflammation?
1. Dilation of the blood vessels
2. Acts with prostaglandins to stimulate nerve endings and cause pain
3. Smooth muscle contraction
4. Increase vascular permeability
5. Increase leukocyte chemotaxis
Describe the plasma kinin cascade
1. The conversion of prekallikrein to kallikrein by prekallikrein activator
2. Kallikrein converts kininogen into bradykinin.
Activator of Hageman factor (factor XII) has what 4 effects on all of the plasma protein systems.
1. Activation of the clotting cascade through factor XII
2. Control of clotting through the production of plasmin
3. Activation of the kinin system
4. Activation of the C1 cascade
3 types of leukocytes
3 types of granulocytes
Monocytes are the precursor for?
The majority of cytokines are defined as?
Interleukins or interferons
Definition of interleukins
Biochemical messengers produced predominantly by macrophages and lymphocytes in response to their recognition of a microorganism or stimulation by other products of inflammation
What are the two major proinflammatory cytokines
IL-1 and iL-6
What are the 2 most important anti-inflammatory cytokines?
IL-10 and TGF-B (transforming growth factor beta)
What is the function of interferons?
Primarily to prevent viruses from infecting healthy cells.
Interferons are produced where?
In virally infected cells.
Inhibition of cytokines will inhibit what
IL-1, 2, 6, and TNF-a
Deleterious effects of exogenous (environmental) antigens.
Disturbance in immunologic tolerance of self-antigens
Immune system of one individual produces an immunologic reaction against another individual
FCER-1 hypersensitivity gene
If inherited from the mother it causes a much larger reaction than if from the father
Neutrophils, Monocytes and Macrophages do what
Phagocytise bacteria and cellular debris
Eosinophils act directly against what
Basophills do what
Act similarly to Mast cells
What do pattern recognition receptors (PRR's) do
Recognize molecular patters on the surface of infectious antigens
What are the 3 subclasses of PRR's ?
- Toll -like receptors
- Complement Receptors
- Scavenger receptors
Chemotactic factors released by mast cells attract what?
Neutrophils and Eosinophils
Leukotrines are also known as what anf what do they do
- AKA Slow Releasing Substances of Anaphylaxis (SRSA)
- Produce effects similar to histamine but much slower
Function of prostaglandins
- Increase vascular permeability
- Increase neutrophil chemotaxis
- Suppress release of histamines and lysosomal enzymens
- Increase the pain response
Function of platelet-activating factor
- Increase vascular permeability
- Causes leukocyte adhesion
- Activates platelet process
What is the effect of atherosclerosis on NO
It covers the inside of the endothelial cell and it then cannot release NO
What effects does NO have?
- Suppress mast cell function
- Decrease platelet adhesion and aggregation
How does IgE attack a parasite?
Parasites elicit an allergic response. This binds IgE which activates mast cells. Mast Cells degranulate, releasing cytotaxtic ECF-A which attracts eosinophils. Eosinophils release caustic proteins on the paratite surface
What is a lymphoine
In interleukin produced by T cells
Example of a chemokine
Function of Interferon Alpha and Beta
If the cell is infected then it has no effect. If it is uninfected it caused the cell to produce antiviral proteins
Interferon is released in response to what
Secreted by virally infected cells in response to double stranded Viral DNA