Galectin-1 promotes HIV-1 infectivity in macrophages through stabilization of viral adsorption.
Following primary infection with human immunodeficiency virus type-1 (HIV-1), macrophages are thought to play an important role, as they are one of the first target cells the virus encounters and can also sustain a significant production of viruses over extended periods of time. While the interaction between the primary cellular receptor CD4 and the virus-encoded external envelope glycoprotein gp120 initiates the infection process, it has been suggested that various host factors are exploited by HIV-1 to facilitate adsorption onto the cell surface. Macrophages and other cells found at the infection site can secrete a soluble mammalian lectin, galectin-1, which binds to beta-galactoside residues through its carbohydrate recognition domain. Being a dimer, galectin-1 can cross-link ligands expressed on different constituents to mediate adhesion between cells or between cells and pathogens. We report here that galectin-1, but not galectin-3, increased HIV-1 infectivity in monocyte-derived macrophages (MDMs). This phenomenon was likely due to an enhancement of virus adsorption kinetics, which facilitates HIV-1 entry. The fusion inhibitors T-20 and TAK779 remained effective at reducing infection even in the presence of galectin-1, indicating that the galectin-1-mediated effect is occurring at a step prior to fusion. Together, our data suggest that galectin-1 can facilitate HIV-1 infection in MDMs by promoting early events of the virus replicative cycle (i.e. adsorption).
Mercier
Simon
S
Research Center for Infectious Diseases, CHUL Research Center, Quebec, Canada.
St-Pierre
Christian
C
Pelletier
Isabelle
I
Ouellet
Michel
M
Tremblay
Michel J
MJ
Sato
Sachiko
S
D002454:Cell Differentiation; D037483:Galectin 1 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015658:HIV Infections / Q000209:etiology*; D015497:HIV-1 / Q000472:pathogenicity*; D006801:Humans; D007700:Kinetics; D008264:Macrophages / Q000821:virology*; D009000:Monocytes / Q000166:cytology; D011994:Recombinant Proteins / Q000378:metabolism; D014780:Viruses / Q000378:metabolism*
D037483:Galectin 1; D011994:Recombinant Proteins