PS is Immunosuppressive:

Journal of Immunology:
2004: Phosphatidylserine Regulates the Maturation of Human Dendritic Cells. Chen, X., et al, Sep 1;173(5):2985-94
* “Taken together, these findings suggest that dendritic cells exposed to PS would fail to initiate and may extinguish cellular immune responses.”

2005: Interaction Between Phosphatidylserine and the Phosphatidylserine Receptor Inhibits Immune Responses In Vivo. Hoffmann, P.R., et al, Feb 1;174(3):1393-404
* “Taken together, these findings suggest that PS inhibits the immune response by inhibiting inflammation in tissue.”

Journal of Biological Chemistry
2006: Apoptotic cells, through transforming growth factor-beta, coordinately induce anti- inflammatory and suppress pro- inflammatory eicosanoid and NOsynthesis in murine macrophages. Freire-de-Lima, C., et al, vol 281, 50, 38376-38384.
* “The induction of TGF-beta itself could be attributed to exposed phosphatidylserine on the apoptotic cells, which therefore appears to drive the balanced inflammatory mediator responses.”

PS is Exploited by Viruses:

Science
2008: Vaccinia Virus Uses Macropinocytosis and Apoptotic Mimicry to Enter Host Cells. Apr 25;320(5875):531-5
* “The induction of blebs, the endocytic event, and infection were all critically dependent on the presence of exposed phosphatidylserine in the viral membrane.”

* “The role of phosphatidylserine in the entry of HIV and other viruses will surely be explored in greater detail now.” Fairn et al, Perspectives: 25 April 2008: Vol. 320. no. 5875: 458 – 460

Nature Reviews: Molecular Cell Biology
2008: Virus plays dead. Heinrichs, A, 9, 422
* “The mature virus membrane is known to be enriched in PS, which is required for infection.
* “By posing as apoptotic bodies, mature viruses may also avoid immune detection.” 

PS as Therapeutic Target

Nature Medicine
2008: Targeting inside-out phosphatidylserine as a therapeutic strategy for viral diseases. Soares et al, December, 2008, 1357-1362
* “Bavituximab treatment cured overt disease in guinea pigs lethally infected with Pichinde virus.”
* “Phosphatidylserine on virions and virally infected cells may enable viruses to evade immune recognition and dampen inflammatory responses to infection.”

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-A