“A brief introduction to the complement system” Euro Diagnostica International Autoimmunity Symposium September 17th, 2012. Malmö, Sweden
Tom Eirik Mollnes
Bordet (1895): Complement lysis 1. Bacteria + Antiserum
2. Bacteria + Antiserum (56 o C, 30´) 3. Experiment 2 + Normal serum
4. Bacteria + Normal serum
Lysis
No lysis Lysis
No lysis
Conclusion: Heat stable (Ab) and heat labile (C) factor
Complement in 1984 Meeting in Royal Society, London. Hobart M. Immunology Today, 1985;5:212.
”Many immunologists hold that complement is baffling or irrelevant or, most conveniently, both but a recent meeting emphasized that complement is interesting and that it may be important, even only as an elegant model system.”
Cascade Principles “Undetonated bombs”
P=Proenzyme E=Enzyme External activator
P1
E1
Autoactivation
Inhibition E2 P2 P2
Biological effects Local vs. systemic
E3 P3 P3 E3
”The point of
E3
no return”
P3
E2
Amplification
P3 E3
Classical pathway
Lectin pathway
Alternative pathway
Microbial surfaces Mannose, NAcGlc
Foreign surfaces
Ag-Ab complexes CRP
CPN
C1q C1r, C1s
C1INH
C3(H2O) Factor I
C4 C4a
MBL MASPs
Factor I
C4bC2
C4
C4BP
C4a
C2b
C3(H2O)B
C4bC2
C2b
P C3bBbP
C3b
C3bC3bBbP
C4b2a3b
Factor I
H
C3a
Natural fluid-phase inhibitors CR1
Ba
C3bB
C3
C4BP
MCP
D
C3(H2O)Bb
C4b2a Factor I
D
H
C5
CPN
DAF
Vitronectin Clusterin
C3aR
C5a C5b C6+C7+C8+C9 Fluidphase
Membrane C4b and C3b inhibitors
CD59
Membrane
C5b-9(m) SC5b - 9 MAC Terminal complement complex
C5aR CR3 C8 C9 C5b-7
CD59
Mollnes, Song, Lambris. Trends Immunol. 2002.
Cross-talk between cascades Complement C1-INHIBITOR
Coagulation Fibrinolysis
KallikreinKinin
Functions of Complement – Protects the host against danger – Fights infections – Cross-talks with other protective systems (e.g. TLR, B- and T-cells)
– Contributes to tissue homeostasis – Physiologic renovation (e.g. C1q/SLE) – Tissue repair and regeneration
– Consequences of activation/dysregulation – Inflammation – Tissue damage and disease
What is inflammation?
Heat
Redness Swelling
Pain
Reduced function
Danger to the host 3 Rs
Danger
Recognition Response
Host
Resolution
Danger signaling Pattern recognition receptors/molecules (PRR/PRM): - Host receptors of Innate Immunity (complement/TLR) Ligands for PRRs: - PAMP: Pathogen Associated Molecular Patterns - “external” (exogenous) danger – microbes - DAMP: Damage Associated Molecular Patterns - “internal” (endogenous) danger – host molecules
Disturbed molecular homeostasis
Recognition by Complement
Harboe and Mollnes. J Cell Mol Med. 2008.
Alternative
pathway activation
Walport MJ. N Engl J Med 2001.
Complement defence against microbes C*
1 Immune adherence CR3
C* C* M AbC*
CR2
C* C*
M
C5aR
2 Chemotaxis Phagocytosis
M
C*
M
C* C*
M
C*
M
C*
C* C*
Inflammation C* Ab C*
3 Immune regulation
M
C*
4 Bacteriolysis
Inflammatory effects mediated by C5a Histamin release
Chemotaxis
Lysosomal enzyme release Neutrophil aggregation
Cell adhesion CR3 (CD11b/18)
Smooth muscle contraction Increased permeability
C5a
CR1 and FcR expression
Reactive oxygen metabolites
Cytokines
Il-1, Il-6, IL-8, TNF
B- and T-cell responses
Arachidonic acid metabolites (LT, PG)
Platelet activating factor (PAF)
Danger signaling Complement and altered self
Complement
REG REG
REG
Cancer cell Normal cell
Apoptotic cell
Endothelial damage
Endothelium and Complement Intact endothelium – The only fully complement compatible surface? • Blocking DAF/MCP induced spontaneous leakage
Damaged endothelium
Capillary leak
– Endothelium is damaged by complement – Damaged endothelium activates complement Arteriosclerosis
Reasons to analyse complement • Complement deficiencies – are associated with certain diseases
• Complement activation – clinical: reflects ongoing disease processes – experimental: animal and in vitro models
• Complement pharmacology – has already reached clinical medicine
CH50 - Total Complement Hemolytic Activity Detection of complement deficiency Sensitized SRBC
Serum
RRBC Mg EGTA
B D P Alternative Classical C1 C4 C2 C3 CH50 CH50 C5
C6 C7 C8 C9 Lysis (Hb release)
Total Complement System Activity Serum is added to micro-titer wells
C5
C6
C7
C8
C9 C5
C3
C6
C7
C4 C2
C1qrs
MBL
Classical pathway
C5
C3
C4 C2
IgM
C8
C9
MASP-2
P
C6
Lectin pathway
C8
C3
FB
Mannan
C7
C9
FD
LPS Alternative pathway
Enzyme immunoassay (EIA) for quantification of TCC (neoepitope) anti-C6
Av-Px Biotin
SC5b-9 anti-C9neo
mAb aE11
Complement deposition in tissue
MPGN II in factor H dysfunction TCC (C5b-9) in glomeruli
Acute Ab-mediated rejection C4d in peritubular capillaries
Complement in the future Therapeutic aspects
Makrides SC. Pharmacol Rev 1998
COMPLEMENT DISEASES
References
Acute Adult respiratory distress syndrome
Zilow et al., 1992; Rinaldo and Christman 1990; Langlois et al., 1989; Meade et al., 1994
Ischemia-reperfusion injury:
Eculizumab (Soliris®)
Myocardial infarct
Hill and Ward, 1971; Earis et al., 1985; Rubin et al., 1989;Fox, 1990; Entman et al., 1991; Kilgore et al., 1994; Homeister and Lucchesi, 1994
Skeletal muscle Lung inflammation
Rubin et al., 1989; Weiser et al., 1996 Ward, 1996, 1997; Eppinger et al., 1997
Hyperacute rejection (transplantation)
Bach et al., 1995; Baldwin et al., 1995; Sanfilippo, 1996; White, 1996; Lawson and Platt, 1996
Sepsis Cardiopulmonary bypass
Hack et al., 1989; Gardinali et al., 1992 Kirklin et al., 1983; Homeister et al., 1992
Burns, wound healing
Ward and Till, 1990; Oldham et al., 1988; Davis et al., 1987; Ljunghusen et al., 1996
Asthma Restenosis Multiple organ dysfunction syndrome Trauma, hemorrhagic shock
Regal et al., 1993; Regal and Fraser, 1996 Niculescu et al., 1987 Miller et al., 1996 Gallinaro et al., 1992;Kaczorowski et al., 1995
Guillain-Barré syndrome
Hartung et al., 1987; Sanders et al., 1986; Koski et al., 1987; Koski, 1990
Chronic Paroxysmal nocturnal hemoglobinuria Glomerulonephritis
Yomtovian et al., 1993; Shichishima, 1995; Rosse, 1997 Couser, 1993; Couser et al., 1985, 1995;Spitzer et al., 1969
C5 PNH
- Paroxysmal nocturnal hemoglobinuria
- GPI-anchor defect (e.g. DAF CD59 )
Systemic lupus erythematosus
Belmont et al., 1986; Hopkins et al., 1988; Negoro et al., 1989; Gatenby, 1991
Rheumatoid arthritis Infertility
Kemp et al., 1992; Satsuma et al., 1993;Abbink et al., 1992 D’Cruz et al., 1990, 1991;Anderson et al., 1993
Alzheimer’s disease
Johnson et al., 1992; Rogers et al., 1992; Pasinetti, 1996; Eikelenboom et al., 1994;Velazquez et al., 1997; Jiang et al., 1994; McGeer et al., 1997; Chen et al., 1996; Morgan et al., 1997
Organ rejection (transplantation)
Platt, 1996; Baldwin et al., 1995; Marsh and Ryan, 1997; Dalmasso, 1997
Myasthenia gravis Multiple sclerosis
Lennon et al., 1978;Piddlesden et al., 1996 Piddlesden et al., 1994
Biomaterials incompatibility Platelet storage
C5a C5b-9
Gyongyossy-Issa et al., 1994
Hemodialysis
Cheung et al., 1994; Himmelfarb et al., 1995; Mollnes, 1997
Cardiopulmonary bypass equipment
Craddock et al., 1977; Haslam et al., 1980;Gillinov et al., 1993; Mollnes, 1997; te Velthuis et al., 1996
Complement in summary
Ricklin D et al. Nat Immunol 2010.