Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
37 Cards in this Set
- Front
- Back
Complement is the major effector of the ______ ______ of the immune system
|
Humoral Branch
|
|
Activation of complement
|
Stimulates a closely regulated cascade of enzymes to facilitate Ag clearance and generate inflamatory response
|
|
2 goals of complement
|
Facilitate Ag clearance and generate a quick inflammatory response
|
|
Three pathways of complement system
|
classical, alternative, and lectin
|
|
Complement components are synthesized in what 3 locations?
|
liver, macrophages, and epithelial cells of the gastric and genitourinary tracts
|
|
Complement makes up _____% of the serum globulin factor
|
15%
|
|
Proenzyme
|
innactive form that when activated can start complement
|
|
Each component of complement has a long/short half life. Explain why this is.
|
They have a short half life so they only act locally and cant travel too far to do damage
|
|
Explain the naming system for complement
|
They each get the letter C followed by a number and sometimes a lower case letter. The lower that letter is in the alphabet the smaller it is. Example: C3a is smalled than C3b.
|
|
If a fragment or combinatin has _____ activity it gets a line above it
|
enzymatic
|
|
MAC stands for...
|
Membrane Attack Complex
|
|
Three pathways to MAC are...
|
classical, alternative, and lectin
|
|
Classical pathway is initiated by what 2 things
|
1. formation of soluble Ag:Ab complexes
2. Binding of Ab to Ag on a suitable traget like bacterial cell |
|
C1q has how many heads and does what
|
It has 6 heads that interact with Ab. Must bind at least 2 of the heads to activate complement
|
|
IgM can activate which pathway
|
classical
|
|
Pentameric IgM gives how many binding sites for C1q?
|
3 binding sites
|
|
Monomeric IgG has how many binding sites and how does this effect the number you need to start complement
|
Only can bind 1 C1q so you need at least 2 to start complement
|
|
Alternative pathway is activated by what
|
It is activated by cell surface constituents foreign to the host. Cell wall components of Gram + and Gram - bacteria especially
**Does not require Ab for activation |
|
Lectin Pathway is activated by what
|
Activated by binding of the pattern recognition receptor MBL
|
|
MBL
|
Mannose binding lection
An acute phase protein that is produced in an inflammatory response. Important innate defense mechanism |
|
What does MAC do
|
Forms a transmembrane channel that disrupts the membrane and allows leakage of small molecules and ions resulting in death
|
|
When MAC's go bad they...
|
Can attack bystander cells which do not deserve killing and this is the basis for autoimmune diseases
|
|
The complement system is non-specific/specific
|
It is non-specific bc it can attack normal host cells as well as microorganisms. **Needs to be closely regulated
|
|
Component lability
|
Very short half lives which doesnt allow them to travel far- 40 nm
|
|
Inactivating regulatory proteins
|
Block the function of complement
|
|
Complement-binding receptors
|
Each circulating RBC and WBC has receptors for complement
|
|
Complement receptors do 2 things
|
1. Mediate many biological activities of the complement system
2. regulate the complement system by binding active complement components and degrading them |
|
Cell lysis is done by which 2 pathways
|
alternative and lectin
|
|
How are cells lysed in complement?
|
Similar to method of enveloped virus where envelope is derived from membrane
|
|
Gram - cells are most susceptible to MAC. When can they not be?
|
Gram negative (-) unless they have built up LPS in cell wall
|
|
Gram positive cells are susceptible as well. When can they not be?
|
If they have built up enough peptiodglycan in their cell walls.
|
|
Nucleated cells are harder lyse because...
|
Unlike RBC's that only require one MAC, nucleated cells require many to lyse a cell
|
|
Infammatory response is initiated by cleavage products that...
|
Bind to receptors on mast cells and basophils and induce degranulation and histamine release
|
|
anaphylatoxins
|
split products that cause degranulation
|
|
Main opsonin of complements system is...
|
C3b
|
|
How does C3b work?
|
It coats immune complex and binds to RBC's which is carried to the liver where it is killed
|
|
Complement deficiencies
|
C3 deficiencies are the most severe
|