Antibodies against myelin in multiple sclerosis sometimes cross react with proteins made by what virus?
a. polio virus
b. encephalitis virus
c. epstein-barr virus
d. multiple myeloma virus

c. Epstein-Barr virus

Explanation:

Multiple sclerosis (MS) is a common chronic inflammation which causes progressive disability due to the demyelination of the central nervous system (CNS).The antibodies made against myelin in multiple sclerosis cross-reacts with the proteins made by the Epstein Barr virus and thus, EBV has been implicated in the development of multiple sclerosis. Epstein Barr virus itself is a DNA containing Herpes virus. 

Six amino acids have side chains that are polar but not charged. these are serine (ser), threonine (thr), cysteine (cys), asparagine (asn), glutamine (gln), and tyrosine (tyr). these amino acids are usually found at the surface of proteins, as discussed in the proteins 2 module.