50 ______________________________________416 5 15 0 36 2 u00d7 10 sup 10 1 3 1 4 u00d7 10 sup 8417 5 15 0 4 4 4 u00d7 10 sup 9 0 54 1 0 u00d7 10 sup 8418 10 5 4 6 5 u00d7 10 sup 7 2 2 u00d7 10 sup 5430 5 15 1 1 5 0 u00d7 10 sup 9 2 1 6 0 u00d7 10 sup 7beta 5 15 0 5 2 0 u00d7 10 sup 8 4 6 6 8 u00d7 10 sup 5______________________________________ u l od sub 600 at ic sub 50 dilution of bacterial extract giving 50 inhibition of cell growth ic sub 50 inhibitory concentration iu international units to confirm and extend these findings ifn u03b2 ifnx416 ifnx418 and ifnx805 were subjected to purification followed by simultaneous antiviral and antiproliferative assay each on 3 different cell lines likewise immunostimulating activity of ifnx416 was compared to ifn u03b2 ifnx418 and ifnx805 see tables 2 3 4 later preparations of ifnx805 gave specific antiviral activities that varied in the range 10 6 10 8 units mg table 2______________________________________antiviral activity of novel modified interferons international units mg ifn protein ifnx no 17 1 chang vero______________________________________cell linex430 3 3 u00d7 10 sup 6 3 1 u00d7 10 sup 7 2 7 u00d7 10 sup 7x416 3 8 u00d7 10 sup 6 3 2 u00d7 10 sup 7 2 0 u00d7 10 sup 7x418 7 1 u00d7 10 sup 4 7 8 u00d7 10 sup 5 2 4 u00d7 10 sup 5beta 1 3 u00d7 10 sup 5 5 1 u00d7 10 sup 5 7.