Case 6 - MS and inflammation Flashcards
what is the composition of the myelin sheath
lipids
glycoproteins
what is the lipid present in the myelin sheath
galactocerebroside
what are the glycoproteins in the myelin sheath
myelin basic protein
myelin oligodendrocyte glycoprotein
myelin associated glycoptoyein
what are only present at the nodes of Ranvier
voltage gated Na+ channels
what is the conduction speed of an unmyelinated axon
0.5-10 m/s
what is the conduction speed of a myelinated axon
150m/s
what is the immune attack against
the oligodendrocytes or Schwann cells
what type of conduction is altered and what does this lead to
saltatory conduction is altered and this leads to axonal degeneration
what is the genetic factor related to MS
chromosome 6 which also contains MHC class genes and myelin proteins
what lymphocytes are activated in the peripheral lymph tissues
CD4+ lymphocytes and CD8+ lymphocytes
what does antigen presentation to naive CD4+ lymphocytes cause
differentiation into various T cell populations
what are the main lymphocytes
Th1 and Th17 - associated with a repertoire of inflammatory cytokines that activate macrophages and opsonising antibodies
Th2 and T regulatory cells which drive humeral immunity or secrete anti inflammatory cytokines
what is there a bias towards in MS patients
bias towards th1 and th17 environment with T regulatory dysfunction that allows inflammation to predominate
what disrupts the blood brain barrier
secreted cytokines and matrix metalloproteinases disrupt the BBB
what does this disruption do
this disruption, along with up regulation of adhesion molecules on the blood vessel endothelium and activation of T cells, allows the T cells to gain entry into the CNS, where additional activation takes place that initiates a damaging inflammatory cascade of events I the CNS
