With no explanation, label each line with "O", "other-biologything", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
``
HIV-1
can
enter
the
microglial
cell
via
CD4
receptors
and
chemokine
co-receptors
such
as
CCR3
,
CCR5
,
and
CXCR4
,
with
CCR5
being
the
most
important
of
these
.
``:O
HIV-1:other-biologything
can:O
enter:O
the:O
microglial:O
cell:O
via:O
CD4:other-biologything
receptors:O
and:O
chemokine:O
co-receptors:O
such:O
as:O
CCR3:other-biologything
,:O
CCR5:other-biologything
,:O
and:O
CXCR4:other-biologything
,:O
with:O
CCR5:other-biologything
being:O
the:O
most:O
important:O
of:O
these:O
.:O