Soluble Mediators In The Immune System Flashcards
(36 cards)
Soluble component in the plasma.
Complement (C’)
Complement is Heat-labile series of _______________, many of which are enzymes (___________).
18 plasma proteins
proteinases
the most important function of the complement
make a hole on the surface of a cell and then result in the lysis of the particle or the cell
Covalently bonded fragments of C3
and C4
Opsonization
C5a, C3a, and C4a; anaphylatoxin leukocyte receptors
Chemotaxis and Leukocyte activation
C5-C9 membrane attack complex
Lysis of bacterial and mammalian cells
C3b and C4b bound to immune complexes and to antigen.
Augmentation of antibody
C3 receptors on B cells and antigen-presenting cells
Responses
C3b and C4b bound to immune complexes and to antigen; C3 receptors on follicular dendritic cells
Enhancement of immunologic memory
C1q; covalently bonded fragments of C3 and C4
Clearance of immune complexes from tissues
Major functions of the complement system
• Involved in opsonization
• Chemotaxis and leukocyte activation
• Lysis of bacterial and mammalian cells
• Augmentation of antibody
• Responses
• Enhancement of immunologic memory
• Clearance of immune complexes from tissues
• Clearance of apoptotic cells
covering of any pathogens that it will be easily identified by the phagocytes
Opsonin
The movement of the cells towards the chemotoxin or away from a chemotoxin, but usually it’s a positive chemotaxis.
Chemotaxis and leukocyte activation
most important function of the complement system.
Lysis of bacterial and mammalian cells
That’s why when we talk about complement, what should come first to our mind is: we
▪ lysis of bacterial cells
▪ lysis of mammalian cells
3 Complement Pathways
Classical
Alternative
Mannose-binding lectin
Pathway that has initiators like
Immune complexes
Apoptotic cells
Certain viruses and gram-negative bacteria
C-reactive protein bound to ligand
Classic Pathway
Pathway with inhibitors like
Various bacteria, fungi, viruses or tumor cells
Alternate pathway
Pathway with initiators like microbes with terminal mannose groups
Mannose-binding lectin pathway
You will see the various steps that are common in the three pathways like:
o Binding of complement proteins to microbial cell
surface or antibody
o Formation of C3 Convertase
o Cleavage of the C3
o Covalent bonding of C3b to microbial formation of
the C5 convertase, which leads to the late steps of
complement activation.
The first initiator of the classical pathway is
immune complexes
Classical pathway starts with _____ and is made up of _____
C1
q r s
▪ like a golf club
▪ The one that attaches itself to the
antibodies
▪ The heads are the one that binds or
attaches itself to the antibodies.
C1q
C3 convertase of Classical pathway
C4b2a
