Which of the following conditions is NOT expected to provide protection against HIV-1 infection of helper T cells?

A) A loss-of-function mutation in the CCR5 gene
B) Treatment with enfuvirtide, a membrane-fusion inhibitor
C) Treatment with concanamycin A, an inhibitor of endosomal proton pumps
D) Treatment with AMD-070, a CXCR4 antagonist
E) Treatment with PRO-542, a soluble decoy protein containing CD4 sequences