Antirhinovirus Activity ofPurine Nucleoside Analogs

Awidevariety ofpurine nucleoside (mainly tubercidin andadenosine) analogs, whichhadpreviously been showntoinhibit thereplication ofa broad spectrum ofRNA viruses, were evaluated fortheir antirhinovirus activity inhumandiploid (WI-38) fibroblasts. Tubercidin, 5-(l-hydroxyethyl)tubercidin, 5-(2-buten-lyl)tubercidin, toyocamycin, andsangivamycin emerged as themostpotentinhibitors. Thesecompounds inhibited thereplication ofrhinovirus types1A,1B,and9atan MIC wellbelow1,ug/ml. However, these compounds proved cytotoxic fortheuninfected hostcells atconcentrations which wereonlyslightly higher (3to10-fold, on theaverage) thanthose required forinhibition ofrhinovirus replication. Themostselective inhibitor ofrhinovirus replication was3-deazaguanine, with aselectivity index of50.Noneofthecarbocyclic andacyclic analogs ofadenosine tested exhibited a potent orselective antirhinovirus activity.