tokens: HIV-1 harboring mutations within two C/EBP sites were crippled in their ability to replicate in U937 promonocytic cells , indicating that these sites are required for replication .
folded_tokens: hiv-1 harboring mutations within two c/ebp sites were crippled in their ability to replicate in u937 promonocytic cells , indicating that these sites are required for replication .
labels: B-virus O O O O B-DNA_domain_or_region I-DNA_domain_or_region O O O O O O O O B-cell_line I-cell_line I-cell_line O O O O O O O O O O