▁repr ess ▁translation ▁of ▁IL - 1 5 ▁m R NA . ▁Trans l ational ▁in active ▁m R NA ▁is ▁stored ▁within ▁the ▁cell ▁and ▁can ▁be ▁induced ▁upon ▁specific ▁signal . ▁Expression ▁of ▁IL - 1 5 ▁can ▁be ▁stim ulated ▁by ▁cy tok ine ▁such ▁as ▁G M - CS F , ▁double - str and ▁m R NA , ▁un m eth yl ated ▁C p G ▁o lig on uc le ot ides , ▁li pop ol ys ac char ide ▁( L PS ) ▁through ▁T oll - like ▁re cept ors ▁( TL R ), ▁inter fer on ▁g amma ▁( IF N - γ ) ▁or ▁after ▁in fection ▁of ▁mon ocy tes ▁her pes ▁virus , ▁My c ob acter ium ▁t uber cul osis ▁and ▁Cand ida ▁alb icans ▁( Fig ure ▁ 2 ). ▁ ▁Sign aling ▁▁ ▁The ▁prev ail ing ▁mechanism ▁of ▁IL - 1 5 ▁action ▁seems ▁to ▁be ▁ju xt ac r ine ▁signal ing ▁or ▁also ▁determined ▁as ▁cell - to - cell ▁contact . ▁It ▁also ▁includes ▁int rac r ine ▁and ▁reverse ▁signal ing . ▁IL - 1 5 ▁was ▁initially ▁character ized ▁as ▁a ▁sol ub le ▁mole c ule . ▁Later ▁it ▁was ▁shown ▁that ▁IL - 1 5 ▁also ▁exists ▁as ▁a ▁memb rane - bound ▁form ▁which ▁represents ▁the ▁major ▁form ▁of ▁IL - 1 5 ▁protein . ▁In ▁memb rane - bound ▁form ▁it ▁could ▁be ▁bound ▁directly ▁to ▁cell