The required number of complexes of a microbial peptide and a particular class II MHC allele on the surface of an antigen-presenting cell to initiate a T cell response specific for the viral peptide is:
A)At least equal to the number of complexes of self peptides with class II MHC on the cell surface
B)Greater than 10³
C)Less than or equal to 0.1% of the total number of class II MHC molecules on the cell surface
D)Greater than 10⁶
E)Zero

Question

Quizplus · Accepted Answer

As few as 100 complexes of a particular peptide and a particular class II MHC molecule are needed to activate naive T cells specific for that complex and thereby initiate a detectable T cell response. This represents less than 0.1% of the total class II MHC molecules on a typical antigen-presenting cell surface.

The Required Number of Complexes of a Microbial Peptide and a Particular