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

Multiple Choice

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