![Page 1: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/1.jpg)
CytotoxicityCytotoxicity
Mitzi Nagarkatti
Professor, Dept. Microbiology and Immunology
Massey Cancer Center
533 Medical Sciences Building
Tel. # 827-1555
![Page 2: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/2.jpg)
Cytotoxicity = Cell killing or lysisCytotoxicity = Cell killing or lysis
EffectorsComplement (C’)
Macrophages (M)GranulocyteNatural Killer (NK) cells Cytotoxic T lymphocytes (CTL)
C’
AgAb
![Page 3: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/3.jpg)
Target CellsTarget Cells
TumorsVirally infected cellsCells infected with intracellular bacteria
![Page 4: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/4.jpg)
MacrophageMacrophageMonocyte - bloodAlveolar Ms–lung Histiocytes – connective tissueKupffer cells – liver Mesangial cells – kidney Microglial cells – brain
![Page 5: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/5.jpg)
Function of macrophagesFunction of macrophagesPhagocytosisAntigen Processing and PresentationCytotoxicity
– Direct Cytotoxicity– Antibody dependent cell-mediated cytotoxicity
(ADCC)
Target
Fc receptor
M
Ag
Ab
![Page 6: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/6.jpg)
Normal Ms are not lytic
Activated Ms are lytic
Activation mediated by Th12 signals required: Cytokine - Interferon- (IFN-)
CD40L
MTarget
MTarget
![Page 7: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/7.jpg)
Mechanisms of Macrophage-Mechanisms of Macrophage-mediated cytotoxicitymediated cytotoxicity
Reactive oxygen intermediates (ROIs): O2-,
OH-, H2O2
Reactive nitrogen intermediates (RNIs): NO, NO2
Tumor necrosis factor-Lysosomal enzymes
![Page 8: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/8.jpg)
Activation of Cytotoxic T lymphocytesActivation of Cytotoxic T lymphocytes
CTL Precursor
Ag Activated
CTL
IL-2
TCR
CD8
IL-2R
Activation Proliferation,Differentiation
Target
MHC Cl. I
Ag
![Page 9: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/9.jpg)
CTL ActivationCTL Activation
Ag + Class I MHC on infected cells/graftsCTL
Ag + Dendritic cells (Class I) – cross priming of naïve CD8+ cells
Ag + APC + CD4+ Th CTL
![Page 10: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/10.jpg)
Characteristics of Effector CTLCharacteristics of Effector CTLIncreased adhesion molecule expression
(LFA-1, CD2, CD44, CD45RO)Decreased expression of L-selectin
(prevents homing to lymph nodes)Expression of VLA-4 (Very Late Ag-4)
which interacts with VCAM-1 (vascular cell adhesion molecule) on endothelial cells leading to inflammation
Production of effector lytic molecules
![Page 11: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/11.jpg)
Mechanism of CTL-mediated killing of Mechanism of CTL-mediated killing of targets targets
Pathways
FasL
Perforin/Granzyme
Cytokines: IFN-, TNF- and TNF-
Fas FasL
Ag
MHC
TCR
Perforin
GranzymeCTL
Perforin
![Page 12: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/12.jpg)
Supramolecular Activation Cluster (SMAC)Supramolecular Activation Cluster (SMAC)
CD43/CD45
MHCp:TCR
LFA-1:ICAM-1
Exocytic vesicles
cSMAC(central)
pSMAC(Peripheral)
Microtubules
CD28:CD80/CD86
Outside of SMAC
Immunologic Synapse between CTL and target cellImmunologic Synapse between CTL and target cell
![Page 13: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/13.jpg)
Natural Killer CellsNatural Killer Cells
Innate immunity Large granular lymphocytesKill virus infected cells and tumor cellsLysis non-MHC restrictedCD3-, TCR-, Ig-
Present in SCID (severe combined immunodeficiency disease) mice
Asialo GM1+, NK1.1+
Intermediate affinity IL-2R+ FcR(CD16)+, Mediate ADCC
![Page 14: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/14.jpg)
Natural Cytotoxicity ReceptorsNatural Cytotoxicity ReceptorsAltered-self Hypothesis Activating Receptor: Contain immunoreceptor
tyrosine-based activation motif (ITAM) Inhibitory Receptor: Contain Immunoreceptor
tyrosine-based inhibitory motif (ITIM)
ITAMITIMITIM
![Page 15: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/15.jpg)
NK Cell ReceptorNK Cell Receptor– KLR (Killer cell lectin-like receptor): CD94, NKG2– KIR (Killer cell Ig-like receptor): Ly49
Human: NKG2A and B are inhibitoryNKG2C and D are activating
Mouse: Ly49H is activatingOther Ly49 is inhibitory
Recognize: Nonclassical MHC: HLA-E – human; Qa-1 – mouse(Classical MHC : HLA-A,B,C,D –human
H-2K,I,D – mouse
![Page 16: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/16.jpg)
Beneficial and Deleterious Beneficial and Deleterious Effects of CytotoxicityEffects of Cytotoxicity
Protection against – Tumors – Virus-infected cells– Intracellular bacteria– Parasites– Fungal infections
Cause – Autoimmune disorders – Transplant rejection– Immunopathology
![Page 17: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/17.jpg)
Cell DeathCell DeathApoptosis
(Programmed cell death) Nuclear and cytoplasmic
condensation Membrane blebs DNA fragmentation
(early, 180bp multiples) Apoptotic bodies Phagocytosis Localizes infection
Ex. Development3H-thymidine-release assay
Necrosis
(Pathologic cell death) Cell Swelling and lysis Inflammation DNA fragmentation
(late, varying size) Spreads infection
Ex. Stress51Cr-release assay
![Page 18: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/18.jpg)
Role of ApoptosisRole of ApoptosisEmbryogenesisOrganogenesisCytotoxic Lymphocyte killing of targets
– FasL – Perforin/Granzyme
Fas FasL
Ag
MHC
TCR
Perforin
GranzymeCTL
![Page 19: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/19.jpg)
In the Periphery
Memory
Resting T Cell
Ag +
-Activated T Cell
CyclingT Cell
Ag
AgIL-2
Activation induced cell death (AICD)
![Page 20: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/20.jpg)
T Cell DevelopmentT Cell Development
Thymus – Central Tolerance• Death by Neglect• Positive Selection: T cells with low affinity
for self MHC • Negative Selection: Deletion of autoreactive
T cells
BoneMarrow
Thymus
MatureT cells
Spleen, LN, Peripheral blood
![Page 21: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/21.jpg)
Apoptosis SignalingApoptosis Signaling
FasL (CD95L)
Fas (CD95)Procaspase 9
Caspase 9
Procaspase 3
Caspase 3
Cytochrome c
Receptor mediated Pathway Mitochondrial Pathway
Bcl-2
Procaspase 8 Caspase 8
Activates DNase, Inactivate DNA repair enzymesDNA fragmentation
FADD (Fas associated death domain)
Apaf-1
![Page 22: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/22.jpg)
Molecules involved in apoptosisMolecules involved in apoptosis
Tumor necrosis factor receptor (TNFR) superfamily:
Fas (CD95)
TNFR (I and II)
Ligands: Induce apoptosis
FasL (CD96L)
TNF – and LymphotoxinLT TRAIL (TNF-related apoptosis inducing ligand)
Bcl-2 family
Bcl-2, Bcl-xL –Inhibit apoptosis
Bax, Bad – Pro-apoptotic
![Page 23: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/23.jpg)
Apoptosis and DiseaseApoptosis and DiseaseLack of apoptosis Cancer Autoimmunity:
– MouseLpr – CD95 deficientGld – CD95 Ligand defectiveLprcg – CD95 intracellular death domain defect
– HumanType Ia Autoimmune lymphoproliferative disease
(ALPS) – CD95 defectType Ib ALPS – CD95L defectType II ALPS – CD95 signaling defect
![Page 24: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/24.jpg)
Induction of apoptosisAIDS and other viral infectionsNeurodegenerative disorder
![Page 25: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/25.jpg)
Suggested ReadingSuggested Reading
Immunobiology: The Immune System in Health and Disease by Janeway et al. 6th ed., 2005. Pg 89-95; 341-361;717.
![Page 26: Cytotoxicity Mitzi Nagarkatti Professor, Dept. Microbiology](https://reader035.vdocument.in/reader035/viewer/2022062418/5565ca09d8b42a8a7b8b4970/html5/thumbnails/26.jpg)
Exam FormatExam Format
Multiple ChoiceEssaysBoth