Plant lectins are potent inhibitors of coronaviruses by interfering with two targets in the viral replication cycle.
We describe the antiviral activity of plant lectins with specificity for different glycan structures against the severe acute respiratory syndrome coronavirus (SARS-CoV) and the feline infectious peritonitis virus (FIPV) in vitro. The SARS-CoV emerged in 2002 as an important cause of severe lower respiratory tract infection in humans, and FIPV infection causes a chronic and often fatal peritonitis in cats. A unique collection of 33 plant lectins with different specificities were evaluated. The plant lectins possessed marked antiviral properties against both coronaviruses with EC(50) values in the lower microgram/ml range (middle nanomolar range), being non-toxic (CC(50)) at 50-100 microg/ml. The strongest anti-coronavirus activity was found predominantly among the mannose-binding lectins. In addition, a number of galactose-, N-acetylgalactosamine-, glucose-, and N-acetylglucosamine-specific plant agglutinines exhibited anti-coronaviral activity. A significant correlation (with an r-value of 0.70) between the EC(50) values of the 10 mannose-specific plant lectins effective against the two coronaviruses was found. In contrast, little correlation was seen between the activity of other types of lectins. Two targets of possible antiviral intervention were identified in the replication cycle of SARS-CoV. The first target is located early in the replication cycle, most probably viral attachment, and the second target is located at the end of the infectious virus cycle.
Keyaerts
Els
E
Laboratory of Clinical & Epidemiological Virology, Department of Microbiology & Immunology, Rega Institute for Medical Research, University of Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium.
Vijgen
Leen
L
Pannecouque
Christophe
C
Van Damme
Els
E
Peumans
Willy
W
Egberink
Herman
H
Balzarini
Jan
J
Van Ranst
Marc
M
D000818:Animals; D000998:Antiviral Agents / Q000378:metabolism / Q000494:pharmacology*; D002415:Cats; D002460:Cell Line; D016765:Coronavirus, Feline / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D019668:Liliaceae; D037121:Plant Lectins / Q000378:metabolism / Q000494:pharmacology*; D045473:Severe acute respiratory syndrome-related coronavirus / Q000187:drug effects* / Q000502:physiology; D053586:Virus Internalization / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
D000998:Antiviral Agents; D037121:Plant Lectins