Innate defences against viraemia

Human blood plasma has been reported to possess nonspecific antiviral activ ity. This activity is due to several preexisting naturally occurring molecu les that are either active against individual members or a family of viruse s. These molecules, however, have not been adequately studied to reveal the ir molecular structures and mechanisms of action presumably because of thei r low and nonspecific antiviral action. Therefore, their possible role agai nst viraemia remains unknown. Recently, two naturally occurring nonspecific broad-spectrum antiviral agents, University of Texas Inhibitor beta (UTI b eta) glycoprotein and high density lipoprotein, have been described in huma n serum. They are active against DNA and RNA viruses and one of them, UTI b eta, possesses significant antiviral activity of 40 units/mL. Since preexis ting antiviral molecules in serum appear to be the only defence mechanisms available at the onset of viral infection they may have protective signific ance against viraemia. In view of this potential, we have undertaken to rev iew the properties of these innate viral inhibitory molecules. Copyright (C ) 2000 John Wiley & Sons, Ltd.