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. 2025 Feb 14;30(4):892.
doi: 10.3390/molecules30040892.

Algal Lectin Griffithsin Inhibits Ebola Virus Infection

Leah Liu Wang  1 , Kendra Alfson  2 , Brett Eaton  3 , Marc E Mattix  4 , Yenny Goez-Gazi  2 , Michael R Holbrook  3 , Ricardo Carrion Jr  2 , Shi-Hua Xiang  1
Affiliations

Algal Lectin Griffithsin Inhibits Ebola Virus Infection

Leah Liu Wang et al. Molecules. .

Abstract

Algal lectin Griffithsin (GRFT) is a well-known mannose-binding protein which has broad-spectrum antiviral activity against several important infectious viruses including HIV, HCV, and SARS-CoV-2. Therefore, GRFT has been brought great attention to antiviral therapeutic development. In this report, we have tested GRFT's activity against the lethal Ebola virus in vitro and in vivo. Our data have shown that the IC50 value is about 42 nM for inhibiting Zaire Ebola virus (EBOV) infection in vitro. The preliminary in vivo mice model using mouse-adapted EBOV has also shown a certain efficacy for delayed mortality compared to the control animals. A GRFT pull-down experiment using viral particles demonstrates that GRFT can bind to N-glycans of EBOV. Thus, it can be concluded that GRFT, through binding to viral glycans, may block Ebola virus infection and has potential for the treatment of Ebola virus disease (EVD).

Keywords: Ebola virus (EBOV); Ebola virus disease (EVD); algal lectin; carbohydrate-binding; griffithsin (GRFT); mannose-binding.

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Conflict of interest statement

Author Marc E. Mattix was employed by the company Nonclinical Pathology Services, LLC. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
GRFT inhibition assays in vitro. Inhibition assay against Pseudovirus EBOV (A) and BDBV (B). Inhibition assay against infectious virus EBOV, which was conducted in BSL-4 containment (C). IC50, 50% inhibition concentration. All samples were tested in triplicate.
Figure 2
Figure 2
GRFT inhibition evaluation in mice. Balb/c mice were used in three groups of eight animals. One group was mock challenged with PBS and mock treated with vehicle. Two groups (EBOV and GRFT) were challenged with 1000 PFU of mouse-adapted EBOV by intraperitoneal injection. The EBOV-only group was treated with vehicle, and the GRFT group was treated with GRFT via a subcutaneous route twice per day. Body weight curves (A) and survival rates (B). The statistical analysis of survival rate was carried out via the Log-rank (Mantel–Cox) program in Prism, with significant difference shown with a p value of 0.0141 between vehicle-treated (red line) and GRFT-treated (green line) mice.
Figure 3
Figure 3
GRFT binding assay. (A) Glycans on the EBOV-GP trimers (~54 glycans/each trimer). (B) GRFT protein presence in the Coomassie blue gel, the size is about 14.5 KD (pointed by the red arrow). (C) Western blot showing GRFT was pull-down by EBOV particles, the GRFT band appeared by anti-His tag antibody as GRFT protein was tagged by 6xHis. If treated with PNGase-F, GRFT did not pull-down by EBOV.
Figure 4
Figure 4
GRFT homologs analysis. (A) Top twelve hits for GRFT homologous protein sequence alignment from a structure-based dataset search using the Phyre2 program [19]. The sequences that exhibit more than 70% homology are shaded in black, identical (*), similarity: lower (.), higher (:). The d2uda1 is GRFT. (B) Comparisons of sequences and structures from GRFT homologous proteins Sequence comparison (b), Superimposition of the top twelve homologous protein structures: side view (a), top view (c), and glycans (mannose, Man) binding model on the surface of GRFT (made from PDB 2GUO) (d).
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