Journal of King Saud University: Science (Apr 2023)
Production of proinflammatory cytokines by expressing Newcastle disease vaccine candidates in corn
Abstract
The efficacy of a plant-based edible vaccine produced in maize by expression of F and HN immunogenic proteins under a seed-specific promoter against Newcastle disease virus (NDV) genotype VII was assessed using cytokine-mediated cellular immune responses in chickens. Using real-time PCR, the mRNA expression of transgenic maize plants was compared to non-transgenic control plants on a relative basis. F and HN genes mRNA expression was found to be 20 and 60 times higher in corn seeds than in leaves, respectively. In maize seeds, 35 µg ml−1 of F protein, or 0.6 percent of total protein, and 41 µg ml−1 of HN protein, or 0.85 percent of total protein, were found using ELISA. The boost in cell-mediated immune response was evaluated in chickens fed with transgenic corn seeds in comparison with control groups. The qPCR analysis showed an increase in the expression of IL-1 (Interleukin-1), IL-2 (Interleukin-2), IL-6 (Interleukin-6), IL-8 (Interleukin-8), IL-10 (Interleukin-10), IL-15 (interleukin-15), Interferon-α, Interferon-β, Interferon-γ, and CCL3 when evaluated at 0, 7th, 14th, 21st, 28th and 35th day in chickens receiving transgenic diet as compared to group 1 receiving non-transgenic diet. The increase in cytokines production was comparable with group 3 immunized with conventional market vaccine. Furthermore, anti-NDV antibodies were also found in the serum of chickens given maize containing immunogenic proteins, but not in the serum of chickens given a regular normal diet, illustrating the antibodies’ specificity produced after feeding. The results demonstrate that transgenic maize consumed orally strongly stimulates the expression of cytokine genes related to cell-mediated immunity, just like commercial vaccines. These results further suggest that these cytokines may be important in initiating cellular immune responses in response to NDV infection.
