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1159
BanLec, a banana lectin, is a potent inhibitor of Middle East respiratory syndrome coronavirus in in vitro assays

Session: Poster Abstract Session: Viral Infections: Treatment and Prevention
Friday, October 10, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
Posters
  • Poster_2014_09_30.pdf (541.0 kB)
  • Background: Middle East respiratory syndrome coronavirus (MERS-CoV) continues to cause human infections with multiple clusters two years after the onset of the epidemic. Though mild cases have been recognized, the infection is severe in those with co-morbidities and >30% of patients die from the infection. Our recent structure-based development of a fusion inhibitor is one of the few treatment options for MERS and it led us to hypothesize that other existing antivirals that block cellular entry may also be active against MERS-CoV. BanLec is a jacalin-related banana lectin that has potent anti-HIV activity through binding to glycosylated viral envelope proteins and blocking cellular entry. We assessed the anti-MER-CoV activity of BanLec in cell culture assays.

    Methods: The anti-MERS-CoV activity of BanLec was assessed by cytopathic effect (CPE) inhibition, viral yield reduction, and plaque reduction (PRA) assays in Vero, Calu-3, and/or HK2 cells. The cytotoxicity of BanLec was also assessed.

    Results: The CC50 of BanLec was >10 nM in Vero and Calu-3 cells. CPE was completely absent in Vero and HK2 cells infected with MERS-CoV on 3 dpi with 30.00 nM of BanLec. In Calu-3 cells, CPE was completely absent at 90.00 nM of the drug. The EC50 of BanLec ranged from 3.99-4.82 nM (Table 1). The mean viral loads reduced by 7.13, 3.40, and 3.63 log10 copies/ml in Vero, Calu-3, and HK2 cells respectively (Fig. 1A to C). The highest percentage of plaque reduction at a concentration of >10 nM of BanLec were 100% and 59.5% in Vero cells and HK2 cells respectively (Fig. 2A & B).

    Conclusion: BanLec exhibits potent in vitro anti-MERS-CoV activity. The detailed mechanism and in vivo correlation of its antiviral activity should be further tested in animal models. The potential advantages of using BanLec for MERS include its high stability and the prospect of using it as a topical treatment or prophylaxis for exposed patients.

    Table 1 Inhibitory effect of BanLec on MERS-CoV replication

    Cell linea

    EC50

    EC90

    EC99

    CC50b

    SIc

    Vero

    3.99 0.22

    7.95 0.21

    8.84 0.20

    >10

    >2.51

    Calu-3

    4.82 0.48

    8.95 0.40

    9.88 0.39

    >10

    >2.07

    HK2

    4.58 0.005

    8.74 0.17

    9.67 0.21

    NA

    NA

    aEC50 was determined by CPE inhibition assay in Vero and Calu-3 cells, and by PRA in the HK2 cells

    bNA, not available

    cSelectivity index = CC50/EC50

     



    Jasper Chan, MBBS, FRCPath1,2, Kwok-Hung Chan, PhD, FRCPath1,2, Dan Boudreaux, PhD3, Michael Swanson, PhD4, David Markovitz, MD3 and Kwok-Yung Yuen, MD5,6, (1)Department of Microbiology, The University of Hong Kong, Hong Kong, Hong Kong, (2)State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, Hong Kong, (3)Department of Internal Medicine, University of Michigan, Ann Arbor, MI, (4)Division of Infectious Diseases, University of North Carolina, Chapel Hill, NC, (5)Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong, (6)State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Pokfulam, Hong Kong

    Disclosures:

    J. Chan, None

    K. H. Chan, None

    D. Boudreaux, None

    M. Swanson, None

    D. Markovitz, Novartis Vaccines: Collaborator, Consultant and Grant Investigator, Research grant, Speaker honorarium and we are patenting the use of the modified lectin for purifying vaccine antigens

    K. Y. Yuen, None

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