Poojashri's started by focusing on the question if the CNS can be considered "immune privileged". She started with reviewing the early works in the field such as Shirai (1921) on rat sarcoma in heterogenous animals (these cells survived in the brain but were rejected in other areas) and by Medawar. She considered four aspects that might lend credence to immune priviledged position of the CNS:
- The barriers (Blood brain barrier, Blood Spinal cord barrier and the Blood CSF barrier)
- The immune system (reduced MHC class I & II expression, immunosuppressive microenvironment of astrocytes
- Immune arc (the afferent and efferent arms )
- Autonomic and endocrine barriers.
She then reviewed the evidence of neuroinflammation and its molecular basis. In particular she explored the role of microglia (the "immune sensor") activation in phagocytosis, chemotaxis, morphological changes, cytotoxic changes etc. Neurons are also known to influence immune function by secretion of various CD class agents. Our own lab's work (Shobha etal 2010) has studied inflammatory response in ALS - reactive astrogliosis (increased NO synthase and S100Beta activity).
Finally Poojashri considered the evidence for neuroprotective effects of neuroinflammation (for example detrimental effects in ALS could be helpful in MS or Parkinsonism). During the open discussion, NF-kB and its role in cellular homeostasis was discussed.