Lipoproteins account for part of the broad non-specific antiviral activityof human serum

Several antiviral substances have been detected in human serum but few have been shown to possess broad antiviral activity. These broadly active antiv iral molecules could be of significance as innate defense mechanisms. We ha ve previously identified and characterized a broadly antiviral glycoprotein , UTI beta, which accounts for 50 antiviral units/ml of human and mammalian sera. In addition there are reports of antiviral activity of human serum a polipoprotein A-1 (apo A-1), an important constituent of high density lipop rotein (HDL), against human immunodeficiency virus (HIV) and herpesvirus. T herefore we investigated (1) whether HDL is broadly antiviral, (2) how much of the broad antiviral activity of serum is due to HDL, and (3) the mechan ism(s) of HDL's antiviral action. In this paper we report that (1) HDL does have broad antiviral activity, (2) HDL accounts for a modest but significa nt portion of the antiviral activity of serum, and (3) HDL acts by preventi ng virus penetration. Overall, HDL may be one of the broadly antiviral defe nces in the bloodstream. (C) 1999 Elsevier Science B.V. All rights reserved .