Gregg A' Hadley, Ph'D'

1
Effector cells and tubulitis in the renal
allograft.
Gregg A. Hadley, Ph.D. Division of
Transplantation Department of Surgery University
of Maryland Medical School
2
Adaptive Immunity to Renal Allografts
Renal Allograft
3

• Interaction of CD8 effectors with graft
  epithelial compartments
• Attack of the renal tubular epithelium by graft
  infiltrating CD8 effector populations is a
  cardinal feature of clinical renal allograft
  rejection.
• Current knowledge of CD8 effector properties is
  derived from studies of leukocyteleukocyte
  interactions
• Consequently, the mechanisms underlying T
  cell/epithelial interactions remain poorly
  defined

4
Generation of kidney-restricted CTL
Responder Spleen Cells
Allogeneic REC Stimulators
Allogeneic SC Stimulators
TARGETS
REC
LC
Percent Lysis
ET Ratio
5
CD103 defines a major subset of CD8 effectors
generated against renal epithelial cells
6

• CD103 Background
• Integrin family heterodimer (formerly aE?7)
• Ligand (E-cadherin) is uniquely expressed by
  cells comprising epithelial layers
• Expressed by gt95 of intraepithelial lymphocytes
  but poorly expressed by peripheral T cells
  (Brenner et al., Kilshaw et al., Lefrancois et
  al. ...)
• Previous studies have focused on the potential
  role of CD103 as a homing receptor that targets
  IEL to the gut mucosa
• Role of CD103 in adaptive immune responses
  remains unclear

• CD103 promotes lysis of REC targets by in vitro
  generated CTL populations Hadley et al., J
  Immunol, 1997 Rostapshova et al., Eur. J.
  Immunol, 1998.

7
Is CD103 expression by CD8 effector populations
relevant to clinical renal allograft rejection?
8
FACS analyses of transplant nephrectomy specimens
2
3
1
CD8
Quad Gated UL 25.41 UR 36.79
LL 35.87 LR 1.93
Quad Gated UL 22.46 UR 23.92
LL 49.91 LR 3.72
Quad Gated UL 20.48 UR 34.80
LL 43.64 LR 1.07
CD103
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Robertson et al., Transplantation 71 306-13,
2001 Wong et al., Transplantation 75 505-14, 2003
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Does a causal relationship exist between
CD103CD8 effectors and destruction of graft
epithelial compartments?
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CD103-deficient mice

• Mice with targeted disruption of the CD103 gene
  (Itgae, chromosome 11) on the BALB/c background
• Comparison of allograft rejection by CD103-/-
  mice vs. wild type mice provides a definitive
  means of documenting the contribution of CD103 to
  the rejection process

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Pancreatic islet transplant model
1) compared to mouse vascularized organ
transplants, islet transplants are relatively
easy to perform and thus amenable to
experimentation 2) islets are specialized
epithelial cells known to express high levels of
the CD103 ligand, E-cadherin, and should be
susceptible to destruction by CD103CD8
effectors 3) rejection of islet allografts
transplanted into streptozotocin treated
(diabetic) mice can be objectively assessed by
serial measurement of blood glucose levels 4)
islets can be transplanted under the renal
capsule which allows recovery and analysis of
graft infiltrating lymphocytes
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CD103CD8effectors are present at the graft site
55
Gated CD8 T cells
CD8
Events
18.13.0 CD103 (n4)
0
100
101
102
103
104
CD103
CD103
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CD103 knockout hosts are deficient in the
capacity to reject pancreatic islet allografts
Graft survival ()
0
20
40
60
80
100
Time (Days)
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Adoptive transfer of CD8 cells into CD103-/-
hosts with long-term islet allografts
Transferred CD8 cells
Blood Glucose (mg/dL)
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Islet allograft in wildtype host at time of
rejection
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Islet allograft in CD103-/- host at day 14 post-Tx
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Conclusion CD103 is required for destruction of
graft epithelial compartments by CD8 cells, and
appears to critically function at the level of
intragraft homing of CD8 effectors
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Do CD8CD103 effectors play a significant role
in rejection of vascularized renal allografts?
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Classical acute rejection model
10
8
6
Serum creatinine (mg/dL)
4
2
Gated CD8 GIL
0
0
2
4
6
8
10
Time (Days)
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Delayed rejection model
CsA 5 mg/kg/day for 10 days
Gated CD8 GIL
CsA
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Two-color Immunostaining Red E-cadherin Brown
CD103
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(No Transcript)
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Anti-CD103 monoclonal antibody, OX-62, blocks
movement of CD8 cells into tubules
100
Plt0.01 n4
80
60
Percent tubules with infiltrating CD8 cells
40
20
0
IgG1 Control
OX-62
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Conclusion CD103 promotes entry and/or retention
of CD8 effectors in the graft renal tubules,
consistent with a key role for CD103CD8
effectors in development of CAN.
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What controls CD103 expression by graft
infiltrating CD8 effectors?
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TGF-beta controls CD103 expression by
allospecific CD8 effectors
In vitro
In vivo
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Working Model
IFN-g
Graft Site
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Acknowledgements Hadley Lab Elena Rostapshova Ye
Feng Rongwen Yuan Riham El-Asady Transplant
Pathology Cinthia Drachenberg