Innate Immunity III Flashcards
What are the important immune proteins secreted by cells?
Cytokines and complement proteins
What are the types of cytokines?
Interleukins, interferons, tumor necrosis, factors,chemokines
What are the complement proteins?
C3 (C3a & C3b)
What is The function of cytokines?
Chemical “messages”: proteins that communicate among cells of the immune system
How are cytokine messages received?
By target cells that have the correct cytokine receptors, which have a high affinity (small cytokine secretion amounts to larger biological response) The response is passed by signal transduction
What are some examples of responses induced by a cytokine?
- Changes in expression
- increase or decrease enzyme activity
- induce proliferation
-Induce differentiation - modulate effector functions
- cell survival/death
- regulating differentiation in hematopoiesis
- role in innate & adaptive immunity
What is the full process of cytokines?
- Inducing stimulus from environment
- Nucleated cell that has cytokine gene releases cytokine
- Signal transduction relays message to target cell which has receptor
- Biological response induced (turn on/ off gene)
What are the 3 modes of cytokine action?
- Plelotropy: same cytokine act on different cells to evoke different responses
- Redundancy: different cytokines evoke same response in cells
- Cascade induction: action of a cytokine on a cell induces production of 1+ additional cytokines
What are some pro-inflammatory cytokines?
- Interleukins (IL) → il-1 and il-6
- tumor necrosis factor (tnf) → TNT alpha
- redundant *
How do chemokines act?
Chemo attractants (cell recruitment)
- call other cells to infection site
Whet is The function of interferons (ifn)?
Antiviral response
What is the full process of phagocytosis?
I. Sensing PAMP/PRR
2. Phagocytosis
3. Starvation / intoxication of phagosome
4. Killing of phagolysosome
5. Signalling by pro-inflammatory cytokine secretion
What is the function of chemokines
-attract immune cells to infected tissues
- can be secretes by immune and non immune (epithelial) cells
- immune cells with chemokine receptors are recruited from the blood into the specific tissue
What are the signs of inflammation?
- DOLOR: pain
- RUBOR: Redness
- CALOR: Heat
4.TUMOR: Swelling - FUNCTIO LAESA: loss of function
What is inflammation? What does it cause?
Dilation and increased permeability of endothelial cells
- increase local blood flow
- leakage of fluids and blood proteins into tissues
- extravasation of immune cells into tissues
- inflammatory cells migrate into tissue, releasing inflammatory mediators that cause pain
* causes heat, redness, & swelling *
What occurs when cytokine guided networks are distrusted?
Initiation of inflammation by innate derived pro-inflammatory yrokindx
What are some speculations of the purpose of a fever? What is fever caused by?
- high temperature for bacteria so reduction the growth rate of microbes
- higher temperature helps immune system function
- higher enzyme activation
- make host realize something is wrong and will rest
- caused by pyrogens *
What is the general response to infection?
Pathogens -> inflammation —> cytokines -> liver(acute phase proteins - complement protein 3) + hypothalamus (fever)
What is the complement system?
50+ serum proteins that cooperates with both the innate and the adaptive immune systems to eliminate pathogens
What are the functions of complement proteins?
- Can directly kill microbes by forming the “Membrane Attack Complex” (MAC)
- Can decorate pathogens to promote phagocytosis (opsonization)
- Can recruit immune cells/inflammation
What is the specific function of complement protein 3?
Helps with opsonization (coating a surface of a pathogen with antibodies and complement proteins which promotes phagocytosis)
What is the function of IFNs?
Produced first after viral infection (followed by NK cells) and together control viral replication
What type of PRRs are required for virus-infected cells?
Endosomal (recognize components released during intro cellular viral replication/degradation like viral nucleic acid)
Surface (recognize components on outside of virus)
Triggers rapid expression of chemokines (attracts NK cells) and IFN (activates NK cells) by infected cell
What is the function of type 1 IFN?
Promote NK cell killing of virus infected cells
