ECSOD regulates immune responses

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EC-SOD regulates immune responses

• Roel van der Veen
• USC
• Los Angeles

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Take home

• Site of anti-inflammatory activity of EC-SOD
  is lymphoid tissue (spleen), rather than the
  inflammatory site itself.

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Outline

• NO and O2- regulate T cell reactivation ex vivo.
• Site of this activity in vivo.

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NO in T cell Activation
Ag
NO
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• O2- may inactivate NO (vascular biology)

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Neutralization of NO activity by PMA-stimulated
WT but not phoxKO (CGD) macrophages
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NO and IFN-? in splenic T cell reactivation
IFN-?KO cells
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NBT precipitation during splenic T cell
reactivation
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NBT precipitation microscopic analysis
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Exogenous SOD enhances NOs inhibitory activity
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O2- and NO regulate immune responses

Ag
NO
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Conclusions part I (Ag-specific spleen cell
activation in vitro)

• NO induction during splenic T cell reactivation
  inhibits proliferation.
• Simultaneous O2- production reverses NOs
  inhibitory activity, resulting in stronger T cell
  proliferation.
• Exogenous SOD enhances NO activity.
• Endogenous EC-SOD reduces O2- activity.
• Basic immune regulatory mechanism?

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EAE induction

• CNS inflammation, resulting in paralysis (MS)
  requires Th lymphocytes.
• Widely used model for immune regulation.
• Active induction
• Immunize with myelin antigen in CFA
• One week later boost
• Passive transfer
• Immunize donors
• After 10 days ? reactivate spleen cells
• Culture 3 days ? inject cells into naïve
  recipients

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Active EAE is suppressed in phoxKO mice
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Possible reasons for EAE resistance in phoxKO

• No pathogenic T cells generated.
• Activation or expansion of pathogenic T cells
  inhibited.
• Inefficient inflammation in the absence of phox.

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Normal antigenic proliferation in draining lymph
nodes from EAE resistant phox-KO mice
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Enhanced NO activity in phoxKO spleen cells
during reactivation ex vivo
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Splenic NO-mediated suppression of EAE is
enhanced in phoxKO mice
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Inflammation and demyelination in spinal cord of
phoxKO mice
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Conclusions from EAE results

• NO and O2- regulate inflammation and
  immunopathology.
• They do so in lymphoid tissue at an early stage,
  regulating T cell activation and the intensity of
  the ensuing immune response, including tissue
  infiltration.

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EC-SOD mimic protects against EAE
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Summary

• NO production, induced during splenic T cell
  activation, inhibits T cell proliferation and
  subsequent inflammation.
• O2- production is enhanced as well, and
  inactivates NO, thereby enhancing immunity.
• EC-SOD increases NO availability, thereby
  reducing immunity and inflammation.

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Implications

• Phox activity is not required for inflammation.
• Instead, phox is required for development of a
  strong inflammatory immune response.
• This could impact not only diseases of immune
  regulation (both hyper- and hypo-inflammatory)
  but also unrelated conditions, such as CGD.
• EC-SOD may be useful as immune modulator in
  unwanted inflammatory conditions

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Acknowledgments

• USC
• Therese Dietlin, Ligaya Pen
• Florence Hofman,PhD.
• NJI
• James Crapo, MD
• NIH
• Steven Holland, MD.

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Patterns of NBT precipitation