INHIBITION OF HUMAN PARAINFLUENZA VIRUS-3 REPLICATION BY INTERFERON AND HUMAN MXA

We have investigated the IFN-mediated inhibition of human parainfluenz a virus-3 (HPIV-3) replication in cultured human A549 cells. IFN-alpha inhibited the virus yield significantly with concomitant reduction of viral RNA accumulation by more than 90%. Further studies indicated th at the inhibitory action of IFN was at the level of primary transcript ion of HPIV3 replication. Since the IFN-inducible protein, MxA, has be en shown to inhibit virus replication in several RNA viruses, we exami ned the role of MxA in HPIV-3 replication using a stably transfected h uman glioblastoma cell line expressing MxA. In these cells HPIV-3 repl ication was decreased by more than 100-fold depending on the virus dos age used with concomitant inhibition of viral RNA synthesis by about 8 0%. However, the viral primary transcription was not affected in this MxA-producing cell line. In contrast, in the parental cell line IFN-me diated inhibition occurred at the primary transcription step of HPIV-3 replication. These data suggest that, in addition to MxA, other IFN-i nducible proteins are involved in the anti-HPIV-3 effect of IFN in bot h the cell lines used. (C) 1996 Academic Press, Inc.