Autoimmunity

1. AUTOIMMUNITY A major cause of morbidity and mortality in the world

3. Many autoimmune diseases are difficult or impossible to cure for the obvious reason that the focus of the immune response – self antigens- cannot be eliminated The ultimate mechanism involves a failure of tolerance and the accumulation of irreversible damage in the target tissues

5. Scheme of immune cell function Central Repertoire Selection Homeostatic expansion Half-life Self agonist selection Antigen-driven expansion Innate cell priming Secondary lymph organ Effector functions DEATH SELF TISSUE SELF TISSUE SURVEY/REPAIR Peripheral pool Regulatory activity Memory

8. Single gene disorders

12. Le modèle murin lpr / gld Mutations de Fas (lpr) ou Fas-L Lymphadénopathie et autoimmunité de type lupique Homme: APLS IL-2 Expansion Mort Tolérance périphérique par délétion Fas-médiée

13. CPA Fas TNF-R Fas-L TNF CD40-L, TNF CD40 Activation Survie Mort Costimulation CD28 -> NF-kB

14. Répertoire périphérique Répertoire naïf tolérisé mémoire Temps

15. Voie Fas Déficit Fas / Fas-L et caspases -> ALPS: Lymphoprolifération et Autoimmunité

16. Impact of single gene disorders on AI Central Repertoire Selection Homeostatic expansion Half-life Self agonist selection Antigen-driven expansion Innate cell priming Secondary lymph organ Effector functions Death SELF TISSUE SELF TISSUE SURVEY/REPAIR Peripheral pool Regulatory activity Memory AIRE FOXP3 FAS

17. Genetics of complex autoimmune diseases

19. Impact of complex gene disorders on AI Central Repertoire Selection Homeostatic expansion Half-life Self agonist selection Antigen-driven expansion Innate cell priming Secondary lymph organ Effector functions DEATH SELF TISSUE SELF TISSUE SURVEY/REPAIR Peripheral pool Regulatory activity Memory

22. From phenotypes to pathogeny

24. Immune complexes Polyclonal Ab Multi-epitope Ag binding Optimal concentrations Deposition on basal membranes and inflammation/destruction

25. Effector mechanisms for Ab

26. Mastocyte activation

27. Complement J. Bordet (1870-1961) C’ is a system of plasma proteins that interacts with pathogens to mark them for destruction by phagocytes

29. Figure 2-20

30. C3 convertase Hydrolysis of C3 causes initiation of the C’ alternative pathway

31. C5 convertase Surface-bound C3 convertase deposits large numbers of C3b fragments on pathogen surfaces and generates C5 convertase activity

32. Small fragments of some Ct proteins can initiate a local inflammatory response C5a

33. C’ inactivation

34. Figure 2-27

35. Figure 2-29

37. Hypersensitivities

42. Effector mechanism in RA GPI / Ig C3b deposition C3 convertase C5 convertase ALTERNATIVE C’ PATHWAY C5a C5aR properdin Fc  R GPI / Ig Factor B Neutrophils Mast cells Fc  R ARTHUS REACTION AMPLIFICATION LOOP

46. Genetic predisposition

48. Family studies in human AIDs Genetic influence Multigenic  s 10-40 0.2-1 2-4 3-4 12-15 Rhumatoid arthritis 0.2 2-5 2-5 24-57 Lupus 0.1 3-5 0-5 25 Multiple sclerosis 0.4 6 0-13 30-50 Diabetes % Non-twin siblings Dizygotic twins Monozygotic twins Population prevalence Concordance rate (%) Disease

49. Backcrosses in mouse

50. MHC: a central player 15% MHC identical siblings MHC weight Other genes 0.4 6 0-13 30-50 Diabetes % Non-twin siblings Dizygotic twins Monozygotic twins Population prevalence Concordance rate (%) Disease

51. Complex diseases Genetic contribution MHC locus Environmental / individual contribution Extrapolated from global familial risk of disease

56. T1D And MHC Conserved Extended Haplotypes 0.14 B57, SC61, DR7 0.21 B44, FC31, DR7 0.22 B7, SC31, DR2 Protective 0.45 B35, SC31, DR5 0.77 B44, SC30, DR4 1.0 B35, FC(3,2)0, DR1 1.0 B60, SC02, DR6 Neutral 2.1 B8, SC01, DR3 4.4 B62, SC33, DR4 5.8 B62, SB42, DR4 14.6 B18, F1C30, DR3 17.0 B62, SC31, DR4 Susceptibility Ratio (T1D:normal) CEHs [ HLA-B, complotype, DR ] CEH type

59. Causal variants Table 2 papier Rioux 10 millions SNPs with a minor allele frequency greater than 1% Common haplotypes

61. Environmental triggers

63. Systemic lupus erythematous

67. Spontaneous murine models of SLE -> Analysis of phenotypes

72. Genetic association studies of systemic lupus erythematosus. Multiple alleles 18q21 151430 Bcl-2 297C/416G 10q24 134638 FAS – 844C 1q23 134637 FASL 230A 10q11.2-q21 154545 MBL AQ0 6p21 120790 C4 TNFB*2 6p21 153440 TNFβ TNF2 6p21 191160 TNFα DR2/DR3 6p21 152700 142860 HLA-DR3, -DR2 PD-1.3A 2q37 600244 PDCD-1 +49G 2q33 123890 CTLA-4 Multiple alleles 1q31-32 124092 IL10 F176 1q22-23 146740 FcGR3A R131 1q22-23 146790 FcGR2A Associated allele(s) Cytogenetic location OMIM a Gene

73. Examples of genetic manipulations that lead to lupus-like disease in mice. No single gene defect is sufficient for lupus development Defective hormone signaling ERα Cytokine production abnormalities TGFβ, IL-10, IFN-γ (Tg) IL-4 (Tg) Dysregulated lymphocyte activation caused by intracellular signaling molecule mutations SHP-1, Lyn, PKC-d, P21, E2F2, Stra13, Gadd45a, Rasgrp1, Fli-1 (Tg), SOCS-1, LIGHT (Tg) TSAd Dysregulated lymphocyte activation caused by receptors and their ligands FcγRIIB, TACI, CD22 TGFβRII, CD45*, PD-1 BAFF (Tg) Defective clearance of apoptotic cells, cell debris, and/or ICs SAP, DNase, Mer, MFG-E8, IgM (secreted), C1q, C4 Defective apoptosis Fas, Fas ligand, Bcl-2 (Tg), IEX-1(Tg) Mechanism Targeted gene product a

74. Lupus nephritis: pathogenic Ab

75. Physiopathology of Lupus Apoptosis defect Defective clearance Of apoptotic cells Loss of tolerance To apoptotic self Complement deficiency Immune complex deposition Hyperactivation of self reactive B cells The tolerance hypothesis The clearance hypothesis

76. The tolerance hypothesis

77. SLE pathogenesis as a progression of successive stages In the lupus prone NZM mouse, Sle1+2+3 are the major susceptibility loci Triple congenic mice on a B6 background reconstitute the pathology (Koch’s postulate) Sle1 C’, Sap Loss of tolerance to chromatin leading to ANA production, B cell defect Sle2, lpr, yaa, Blys Progressive expansion of autoimmune response with epitope spreading Sle3 Dysregulation of CD4+ T cells, non T-cell autonomous Sle6 FcR End organ damage culminating in fatal lupus

78. Physiopathologie du lupus D’après Morel et al, Immunity 1999 Sle1 Sle2,3 Lpr, gld, yaa Sle6 Rupture de tolérance / chromatine ANA Expansion, ANA ++ Lésion d’organe Lupus fatal NZM loci

82. Regulating the Sle1 effect Sle1 Sle2,3 Lpr, gld, yaa Sle6 Rupture de tolérance / chromatine ANA Expansion, ANA ++ Lésion d’organe Lupus fatal Sles1 Sles1 is present in the lupus-prone NZM strain and attenuates the pathology in this strain via epistatic interactions

83. The clearance hypothesis

84. Apoptotic cells must be cleared At least two steps: - clearing - digesting and masking

86. Phagocyte receptors

90. Le rôle du complément D’après Janeway-Travers, Immunobiology

92. Le facteur H régule l’activation du C’

93. CR1, récepteur à C3b, C4b, iC3b (CD35) Expression par B, neutro, mono, GR, FDC, ep glomérulaire Cofacteur de I (serine estérase) et H : conversion C3b -> C3bi Fonction d’opsonisation des structures fixant C3b, C4b , iC3b Rôle régulateur des seuils d’activation du lymphocyte B

95. Pentraxins Protomers Oligomers CRP SAP

97. C-reactive protein complexed with phosphocholine 5 non covalently associated protomers, symmetrically arranged around a central pore

98. Plasma membrane asymmetry phosphatidylserine and phosphatidyletholamine phosphatidylcholine and sphingomyelin glycosphingolipids

99. Interaction of CRP with C1q Recognition face binds ligand : « masking effect » ? Effector face binds C1q or Fc  R

102. C’ bridges innate and adaptive immunity Carbohydrate-rich particles lacking sialic acid Immune complexes Non immune molecules (CRP, SAP, polyanions, Microbial ligands)

104. Déficit en complément et prédisposition au lupus % LUPUS Homme Concordance Souris entre jumeaux C1q 93 90 ++ C1r/s 57 67 C4A/B 75 80 ++ C2 10 +/- C3 rare - MAC rare -

106. Cellules apoptotiques, source d’autoantigènes ? Auto-anticorps du lupus Corps apoptotiques a) Ag intracellulaires -> chromatine intracellulaire + -> spliceosome + -> snRNP + b) Antigènes membranaires : Phospholipides (PS) + c) Protéines plasmatiques :  2 glycoprot I, C1q + Ag ubiquitaires, abondants => rupture de tolérance improbable NéoAg ? Externalisation Ag CA in vivo rares ?

107. Présentation antigénique par les CPA infection capture réplication Virus MHC TCR T CPA Signal 1 MHC I MHC II Voie exogène Voie endogène

108. Expérience: 1. Immunisation de souris avec des tumeurs syngéniques apoptotiques 2. Injection de tumeurs normales -> mort ? A) Immunisation avec des DC « pulsées » -> protection anti-tumorale => immunisation B) Immunisation avec des Macrophages -> croissance tumorale => tolérance Conclusions 1. Les cellules apoptotiques peuvent être immunogènes 2. La CPA impliquée (ou son état) décide de l ’issue D ’après Ronchetti et al, 1999

109. Cross-Présentation antigénique Corps apoptotiques MHC TCR T CPA Signal 1 MHC I MHC II Voie « croisée » Régulation ?

111. C’ et inflammation C’ consommé en phase active de lupus - C1q, C2, C4, plus rarement C3 (formes sévères) Dépôt de C’ -> associé aux IC -> pas strictement corrélé aux lésions tissulaires Clairance des IC : CR versus FcR ? Rôle des anticorps anti-C1q ? -> Vascularite urticariante (HUVS) -> Lupus (1/3 patients +)

112. Expérience: 1. Péritonite stérile (thioglycolate IP) -> macrophages péritonéaux 2. Injection de thymocytes apoptotiques -> clairance in vivo ? Souris Clairance Lupus Contrôle +++ - C1q KO - +++ C4 KO + ++ C3 KO +++ - Conclusion: La déplétion en C1q entrave la phagocytose des corps apoptotiques et prédispose au lupus

113. CPA Virus CPA primée Le deuxième signal est induit par l ’inflammation et permet l ’expression des molécules B7 par les CPA Inflammation poly Antigène Signal 1 Signal 2 B7 TCR CD28 Virus BCR T B = CPA HELP Anticorps Effecteurs Le rôle de l ’inflammation

114. Apoptose et inflammation macrophage CPA primée B7 Elimination discrète ! Agitateurs Toll, IFN, TNF, IL-1 Convocation du lymphocyte et identification du cadavre Cross-présentation Co-stimulation Recrutement Toll

115. Corps apoptotique Phospholipides annexin V,  GPI C1q Ag nucléaires snRNP 1. Expression des autoAg à la membrane des corps apoptotiques 2. Clairance médiée par les auto Ac -> capture Fc  R-dépendante 3. Consommation de C1q -> perte du pouvoir « solubilisant » du C ’ pour les complexes immuns 4. Conséquence systémique -> dépôts d ’IC dans les tissus 5. Début des lésions tissulaires Le rôle des auto-anticorps ?

116. Corps apoptotique Macrophage Cellule dendritique C ’ PCR Corps apoptotique C ’ PCR Auto Ac CR1, CD36, …. CR1, CD36, …., FcR IL-1, TNF  Présentation croisée TGF  , IL-10 Rupture de tolérance Tolérance FcR ?

117. Corps apoptotique Macrophage « Eat me » signals « Cool down » or « Turn me on » signals CHO iC3b PS C1q b2GPI TSP ox LDL CD14 lectin b2 intégrine PS-R C1q-R CR1 CD36, intégrines CD68 ... Distribution tissulaire des récepteurs - différentielle - régulée Fonctions différentes des récepteurs Tether -> Trigger

118. Apoptose Clairance Prédisposition Déficit en C ’, CRP, … Défaut de maturation des CPA... Excès de mort Lésion Lupus Infection Gènes etc Gènes

119. Autoantibody-mediated pathogenesis of SLE. Lymphocyte activation in GC IC formation Tissue inflammation and lesions Apoptosis defect But not all autoAb and IC are pathogenic

120. D’après Immunological Rev, 2001 Clairance des IC: rôle du C’ et des GR

121. Additional factors

122. Lymphocyte activation defect Multiple alleles 18q21 151430 Bcl-2 297C/416G 10q24 134638 FAS – 844C 1q23 134637 FASL TNFB*2 6p21 153440 TNFβ TNF2 6p21 191160 TNFα PD-1.3A 2q37 600244 PDCD-1 +49G 2q33 123890 CTLA-4 Multiple alleles 1q31-32 124092 IL10 Associated allele(s) Cytogenetic location OMIM a Gene

125. Excessive inflammation Chronic IFN pathway activation

126. The IFN signature

127. Abnormal lymphoid organs

128. Abnormal cell positioning ?

132. Figure 2-21

133. Figure 2-22

134. Figure 2-22 part 1 of 2

135. Figure 2-22 part 2 of 2

136. Figure 2-23

138. Figure 2-24

140. Figure 2-25

142. Figure 2-34

143. Figure 2-35

145. Figure 2-36

146. Figure 2-37

148. Figure 2-31

149. Figure 2-32