Human non-pregnancy ribonuclease with anti-Kaposiʹs sarcoma activity

Our demonstration of a 19 kDa anti-Kaposiʹs sarcoma (KS) ribonuclease (RNase) in urine from a non-pregnant female may provide at least part of the explanation for the low incidence of KS in human females. N-terminal sequence analysis and isoelectric focusing of the purified RNase, coupled with the very low levels of anti-KS activity noted for recombinant forms of human eosinophil derived neurotoxin and human eosinophil cationic protein, suggest that the 19 kDa enzyme is an eosinophilic protein whose potent anti-KS activity is dependent upon post-translational modifications that occur only in human cells.