A composition includes a Euglena biomass lysate having an average particle size of about 2.0 to 500 micrometers and cellular components, including beta-1,3-glucan as at least about 90 percent linear, unbranched beta-1,3-glucan polysaccharide polymers having an average molecular weight of 1.2 to 580 kilodaltons (kDa) and beta-glucan polymer chains having a polymer length of about 7.0 to 3,400 glucose monomers. Residual media remains from a heterotrophic fermentation process that produced a Euglena biomass and the Euglena lysate. Vitamin C is added in an example, and the weight ratio of the beta-1,3-glucan to the added vitamin C is in the ratio of 1:10 to 1:1 and may be in different delivery forms. The composition may include other added immune response inducing components.
