The Immune Response in Time and Space

Transcription

1 The Immune Response in Time and Space Chapters 14 & 4 Sharon S. Evans, Ph.D. Department of Immunology sharon.evans@roswellpark.org September 18 & 23, 2014

2 Inflammation Inflammation Complex response to infection, local injury, trauma Involves numerous immune system cells, cytokines Heat Redness Swelling Pain Depends on controlled migration of leukocytes Adapted from Nature Immunology, December 2005

3 Logistics of Leukocyte Trafficking *Neutrophil-derived HBP (heparin binding protein) increases vascular permeability; chemoattractant for monocytes) Nature Medicine 7, 1123, 2001 J Immunology, 174: 6399, 2005

4 Objectives Be able to read and understand field of adhesion and leukocyte trafficking. Have general understanding of the molecules that mediate lymphocyte entry into lymphoid organs. Understand molecular basis of cytokinedriven leukocyte trafficking during acute and chronic inflammation.

5 Outline Leukocyte trafficking the multistep paradigm Cell adhesion molecules Chemokines Homeostatic lymphocyte recirculation Mechanisms of lymphocyte extravasation Cytokine-dependent inflammatory process Other mediators of inflammation Anti-inflammatory agents

6 General Concepts: Cell Adhesion Molecules and Chemokines Orchestrate Leukocyte Migration Extra-lymphoid sites of inflammation Liver Pancreas Kidney Heart Lung, etc Lymph Node HEV Peyer s Patch HEV Constitutive Trafficking Venule Neutrophil Endothelial cell Inflammation Monocyte Inducible Trafficking T cell Efficiency of migration depends on: Cell adhesion molecules (CAM) Chemokines

7 Cell Adhesion Molecules (CAMs) Also Regulate Lymphocyte Activation Immunological Synapse LFA-1 / TcR Friedl P et al., Nature Reviews Immunology 5, (July 2005)

8 Multistep Adhesion Cascade Required at All Sites of Leukocyte Extravasation* Flow Selectins Chemokines Ig family-cam CD31/JAMs *Adhesion overcomes hemodynamic flow/shear Trafficking mechanisms evolutionarily conserved

9 Outline Leukocyte trafficking the multistep paradigm Cell adhesion molecules Chemokines Homeostatic lymphocyte recirculation Mechanisms of lymphocyte extravasation Cytokine-dependent inflammatory process Other mediators of inflammation Anti-inflammatory agents

10 Tethering/ rolling Arrest/ adhesion

11 CD31 For Reference..

12 For Reference..

13 Outline Leukocyte trafficking the multistep paradigm Cell adhesion molecules Chemokines Homeostatic lymphocyte recirculation Mechanisms of lymphocyte extravasation Cytokine-dependent inflammatory process Other mediators of inflammation Anti-inflammatory agents

14 Chemokine Structure C C Similar polypeptide fold as cytokines although less α-helical regions Small molecular weight (8-10 kda) High binding affinity for receptor K d ~10-9 M CC chemokine conserved cysteines are contiguous CXC chemokine conserved cysteines are separated by amino acid (X) Housekeeping chemokines (constitutive) vs inflammatory chemokines

15 CCL21 (SLC)

16 Bacterial Chemoattractant Directs Neutrophil Migration Janeway C 7 th Edition Immunobiology, 2007

17 Direction of migration Chemokines Stimulate Chemotaxis and Migration CXCL8 Chemokine origin Assay used to define functional chemokine/chemokine receptor partners Chemokine concentration gradient Cells migrate toward chemokine (and stop) if they express appropriate chemokine receptor Origin for cells

18 Chemokine source Neutrophil Chemotaxis

19 Profile of Expression of Leukocyte Chemokine Receptors Ag/TcR CD80/86-CD28 Cytokines CXCR1 CXCR2 CXCR3 CXCR4 CCR7 * Constitutive vs inducible chemokine R expression

20 Naïve T cell CCR7 T H 1 T cell CXCR3 (CXCL10) T H 2 T cell CCR4 (CCL27)

21 Differential Chemokine Receptor Expression by CD4 Th Subsets a-cd3 a-cd28 IL-12, IFN-γ (Stat4, STAT1) Th1 (T-bet) CR CXCR3 CCR5 CCL/CXCL CXCL9/10 CCL5/CCL3/ CCL4 APC MHC II CD4 Thp IL-4 (Stat6) Th2 (GATA-3) CCR3 CCL11 TGF-β+IL-6, IL-23 (SMAD3, Stat3) TGF-β, IL-2 (SMAD3, Stat5) Th17 (RORgt) CCR6 CCL20 itreg Foxp3 CCR4 CCL22

22 * Chemokine receptors bind > 1 chemokine Chemokines bind > 1 receptor

23 Signaling occurs in milliseconds adhesion chemotaxis

24 Outline Leukocyte trafficking the multistep paradigm Cell adhesion molecules Chemokines Homeostatic lymphocyte recirculation Mechanisms of lymphocyte extravasation Cytokine-dependent inflammatory process Other mediators of inflammation Anti-inflammatory agents

25 Lymphocyte Migratory Pathways: Recirculation vs Recruitment & Peyer Patches

26 Adaptive Immunity is Generated in Lymph Nodes or Peyer Patches Peripheral tissues Skin Lungs GI tract Genitourinary tract Soluble Ag Ag-loaded DCs Afferent lymphatics Draining Lymph Node HEV HEV High endothelial venule (HEV) Efferent lymphatics Naive cell entry

27 Dendritic Cells Congregate at Point of T Cell Entry Across HEVs: Optimal Opportunity for Antigen Presentation DC / T cell / Collagen + FITC Dextran Mempel, T.R., Henrickson, S.E. and von Andrian, U.H. Nature 427: 154, 2004

28 Naïve Lymphocytes Traffic Preferentially Via HEVs Lymphocyte / HEV Inject TRITC-labeled naive T cells 30 min. Stain PLN with HEV-specific (mucin = PNAd) mab (green) Chen et al Nature Immunol 2006 Chen et al Microcirculation 2009 Chen et al Immunity 2004 HEV

29 Thermal Naïve Stress Lymphocytes Improves Traffic Trafficking Across Preferentially Lymphoid Organ Via HEVs HEVs Extralymphoid Sites Liver Pancreas Kidney Heart Lung Lymph Node HEV Peyer s Patch HEV HEV Chen et al Nature Immunol 2006 Chen et al Microcirculation 2009 Chen et al Immunity 2004

30 Dynamics of Lymphocyte Trafficking: Resting Lymph Node Entry: Naïve CM DC HEV Exit: S1P/S1P 1 Lymphatics Homeostatic Trafficking Entry Rate = Exit Rate High throughput screening ~ 1-10 in 10 6 T cells express specific Ag receptor ~ 1.5 x 10 4 /sec (sheep) L-selectin PNAd CCR7 CCL21 LFA-1 ICAM-1/ICAM-2 Total number of lymphocytes remains constant

31 Dynamics of Lymphocyte Trafficking: Shut-Down Response in Inflamed Lymph Node Entry Rate > Exit Rate Entry: Naïve CM Exit: DC HEV S1P/S1P 1 Accumulation of naïve, CM lymphocytes Arteriole dilation, increased number of HEVs (Soderberg, PNAS, 2005; Webster JEM 2006: Chyou JI 2008) Increased vascular display of CCL21 & ICAM-1 on HEVs (Chen, Nature Immunol 2006; Microcirculation 2009) CD69-dependent decrease in S1P 1 (Shiow, Nature, 2006) Lymphatics

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33 Lymph Node Enlargement during Inflammation Due to Increased Entry and Decreased Exit Lymph node size and HEV density post HSV infection Response to HSV2 infection: Soderberg et al., PNAS (2005)

34 Outline Leukocyte trafficking the multistep paradigm Cell adhesion molecules Chemokines Homeostatic lymphocyte recirculation Mechanisms of lymphocyte extravasation Cytokine-dependent inflammatory process Other mediators of inflammation Anti-inflammatory agents

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37 Frozen-Tissue Section Adherence Assay Naïve T cells Lymphocytes + L-selectin blocking Ab Lymph node 12 mm 30 min. at 4 0 C rotation Adherent lymphocyte

38 Naïve Lymphocytes Bind Through an L-Selectin- Dependent Manner to Lymph Node HEV In vitro assay measures naïve lymphocyte adherence to HEV in tissue section Control L-selectin blocking Ab Appenheimer M Eur J Immunol 2007; Chen Q Immunity 2004; Chen Nature Immunol 2006 See also Figure 13-7c

39 Unique Combinations of CAM & Chemokines Direct Lymphocyte Trafficking to Various Tissues Lymph node * CCL21 CCR7

40 Naïve T cell L-selectin hi CCR7 hi LFA-1 intermed LN and PP HEVs Activated T cell (effector/memory) L-selectin lo CCR7 lo LFA-1 hi α4β7 integrin hi CCR4 CLA hi (E/P-selectin L) CXCR3 hi Lamina propria Skin

41 (α4β7 integrin) *

42 Outline Leukocyte trafficking the multistep paradigm Cell adhesion molecules Chemokines Homeostatic lymphocyte recirculation Mechanisms of lymphocyte extravasation Cytokine-dependent inflammatory process Other mediators of inflammation Anti-inflammatory agents

43 Multistep Paradigm Governing Leukocyte Recruitment is Evolutionarily Conserved (Injury in Zebra fish) Janeway C 7 th Edition Immunobiology, 2007

44 Enhanced Leukocyte-Endothelial Interactions During Acute Inflammation Constitutive low Normal Vessels Inducible high Inflamed Vessels Fisher, D, Immunol Invest 2006 Inflammatory cytokines responsible?

45 Inflammatory Cytokines (TNF, IL-1β, IFN-γ, IL-6) Upregulate Adhesion Molecules, Chemokines TNF Classical NFκB signaling pathway TNFR Endothelial cell NFκB signaling pathway NFκB P AP1 NFκB STAT3/1 SP1 icam1

46 Shah Int J Hypertherm 2002, Fisher Immunol Invest 2006, Chen Nature Immunol 2006 Endothelial Responses to TNF-α Endothelial Cells (in vitro) Control CXCL8 (IL-8) TNF-a pg/ml Control NT ICAM-1 Endothelial Cells (in vivo) NT CD31 Leukocyte/CD31 Inflamed vessels TNF-α

47 Outline Leukocyte trafficking the multistep paradigm Cell adhesion molecules Chemokines Homeostatic lymphocyte recirculation Mechanisms of lymphocyte extravasation Cytokine-dependent inflammatory process Other mediators of inflammation (kinin, clotting system, fibrinolytic/plasmin, complement/anaphylatoxins, lipids) Anti-inflammatory agents

48 IL-6, IL-4, TNF, IL-1 CCL3, CCL4, CCL5 Resident cell IL-6, TNF CCL3, CCL4 * Cells & mediators involved in local acute inflammatory response

49 Chronic Inflammation TNF-α and IFN-γ central to development of chronic inflammation IFN-γ released by T H 1 cells, NK cells, cytotoxic T cells TNF-α one of principal cytokines secreted by activated macrophages. IL-1, IL-6 also contribute Regulate synthesis of other cytokines, chemokines, adhesion molecules

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51 Outline Leukocyte trafficking the multistep paradigm Cell adhesion molecules Chemokines Homeostatic lymphocyte recirculation Mechanisms of lymphocyte extravasation Cytokine-dependent inflammatory process Other mediators of inflammation Anti-inflammatory agents

52 Mackay, CR Nature Immunol 9:988, Sept. 2008

53 Chemoattractant Targets in Rheumatoid Arthritis C5aR C5a C5a is one of the most potent chemoattractants for neutrophils and eosinophils; activates mast cells, macrophages, and basophils. Mackay, CR Nature Immunol 9:988, Sept. 2008

54 Chemokine Targeting in Cancer CXCL12 CXCR4 Competitive inhibitor Chemokine Therapeutics Corp

55 SUMMARY Leukocyte trafficking the multistep paradigm Cell adhesion molecules Chemokines Homeostatic lymphocyte recirculation Mechanisms of lymphocyte extravasation Cytokine-dependent inflammatory process Other mediators of inflammation Anti-inflammatory agents