Fucoidan But Not 2'-Fucosyllactose Inhibits Human Norovirus Replication in Zebrafish Larvae

Abstract

Human noroviruses (hNoVs) cause heavy disease burden worldwide and there is no clinically approved vaccination or antiviral hitherto. In this study, with the use of a zebrafish larva in vivo platform, we investigated the anti-hNoV potentials of fucoidan (from brown algae Fucus vesiculosus) and 2'-Fucosyllactose (2'-FL). As a result, although both fucoidan and 2'-FL were able to block hNoV GII.4 virus-like particle (VLPs) from binding to type A saliva as expected, only fucoidan, but not 2'-FL, was able to inhibit the replication of hNoV GII.P16-GII.4 in zebrafish larvae, indicating the possible needs of higher molecular weights for fucosylated carbohydrates to exert anti-hNoV effect.

Keywords: 2′-fucosyllactose; antiviral; fucoidan; norovirus.

Figure 1

Percentage (%) of norovirus (NoV) GII.4 virus-like particles (VLPs) pre-incubated with fucoidan, 2′-Fucosyllactose (2′-FL) or human milk binding to type A saliva (OD₄₅₀) in comparison to positive control (NoV GII.4 VLPs without carbohydrate blocking). Each column represents the average of triplicates, and each error bar indicates the standard deviations.

Figure 2

Detection of human norovirus (hNoV) GII.P16-GII.4 with and without pre-incubation with fucoidan or 2′-Fucosyllactose (2′-FL) from zebrafish larva at 0 and 2 dpi. Each sample contains a pool of 10 larvae. Each column represents the average of four independent experiments conducted in four different weeks, and each error bar indicates the standard deviations. * Below the limit of detection (1.3 log genome copies/sample). ** Two out of three samples were below the limit of detection.