Some viruses evade CTL-mediated immunity by expressing molecules that have which of the following actions?
A)Inhibition of the TAP peptide transporter
B)Inhibition of proteolysis of the invariant chain
C)Stimulation of proteasome activity
D)Activation of immune regulatory factors (IRFs)
E)Inhibition of IL-5 production

Question

Quizplus · Accepted Answer

CTL killing of virus-infected cells requires presentation of viral peptide-class I MHC complexes on the cell surface.The class I MHC pathway of antigen presentation,which generates the peptide-class I MHC complexes,depends on TAP transporter.TAP pumps cytosolic peptides,generated by the proteasome,into the ER where they bind to newly translated class I MHC molecules.Many viruses carry genes that encode inhibitors of different parts of the class I MHC pathway,including TAP transporter,the proteasome,and others.Proteolysis of the invariant chain is required for the classs II MHC pathway of antigen presentation,Activation of IRFs would enhance CTL mediated immunity by upregulating class I MHC expression.IL-5 does not influence CTL activity.

Some Viruses Evade CTL-Mediated Immunity by Expressing Molecules That Have