Previously, we compared the immunogenicity of
purified RGNNV VLPs with that of intact yeast (S. cerevisiae)
producing RGNNV VLPs in oral immunization in the mouse
model (Kim et al., 2014b). We found that the intact yeast
elicited a significantly higher level of neutralizing antibody
against RGNNV than purified RGNNV VLPs (Kim et al.,
2014b). Also, previous studies have indicated that yeast
itself has an adjuvant effect in the digestive tract of
vertebrates (Lee et al., 2013). Therefore, we expect that
whole yeast producing RGNNV VLPs or extracts of such
yeast, have potential as oral vaccines in fish.