C-type lectins DC-SIGN and L-SIGN mediate cellular entry by Ebola virus in cis and in trans

Abstract

Ebola virus is a highly lethal pathogen responsible for several outbreaks of hemorrhagic fever. Here we show that the primate lentiviral binding C-type lectins DC-SIGN and L-SIGN act as cofactors for cellular entry by Ebola virus. Furthermore, DC-SIGN on the surface of dendritic cells is able to function as a trans receptor, binding Ebola virus-pseudotyped lentiviral particles and transmitting infection to susceptible cells. Our data underscore a role for DC-SIGN and L-SIGN in the infective process and pathogenicity of Ebola virus infection.

FIG. 1.

DC-SIGN-mediated infection of K562-DC-SIGN cells. K562 and K562-DC-SIGN cells were infected with VSV-G-, Ebola virus Zaire (Ebo-Z)-, or Ebola virus Reston (Ebo-R) GP-pseudotyped lentivirus in the absence (control) or presence of the DC-SIGN-specific monoclonal antibody MR-1. Infectivity was measured as luciferase activity 48 h postinfection. One representative experiment out of three is shown.

FIG. 2.

(A) Jurkat cells expressing DC-SIGN and L-SIGN are permissive for Ebola virus infection. Control Jurkat cells or Jurkat cells expressing DC-SIGN or L-SIGN by transduction with a retroviral vector were infected with Ebola virus Zaire (Ebo-Z) or Reston (Ebo-R) GP-pseudotyped lentivirus (mean ± standard error, n = 3). (B) Specificity of DC-SIGN- and L-SIGN-mediated infectivity of Jurkat cells. DC-SIGN- and L-SIGN-mediated infectivity of Jurkat cells transduced with the retroviral vectors mentioned above was assessed by preincubation with mannan and specific monoclonal antibodies: MR-1 is DC-SIGN specific, and DC28 exhibits specificity for both DC-SIGN and L-SIGN. Results are shown as the percentage of luciferase activity compared to that of the untreated cells (mean ± standard error, n = 3). Mannan was tested once on Jurkat-DC-SIGN. DC28 was used only for Jurkat L-SIGN.

FIG. 3.

MDDC bind Ebola virus GP-pseudotyped particles and transmit infectivity to susceptible cells. MDDC were incubated with infectious supernatants containing VSV-G-, Ebola virus Zaire (Ebo-Z)-, or Ebola virus Reston (Ebo-R) GP-pseudotyped lentiviruses after a brief preincubation in the absence or presence of MR-1 DC-SIGN-specific monoclonal antibody. Cells were extensively washed thereafter and plated onto HeLa cells. The same amount of infectious supernatant (Sup) without incubation with DC was directly added to the HeLa cells as a control of the original infectivity. Cells were assayed for luciferase 48 h after infection. The experiment was performed with cells from two independent donors, and a representative result is shown.