Factors secreted by CD8(+) T cells have been described to suppress imm
unodeficiency virus replication. The research efforts to identify thes
e factors led to the proposal of some candidate proteins as being resp
onsible for the antiviral effects. Chemokines and IL-16 are secreted b
y CD8(+) T cells and inhibit HIV replication through different mechani
sms. However, their antiviral properties cannot fully explain the inhi
bitory activities found in cell culture supernatants from CD8(+) T cel
ls.