Vitamin A or E and a catechin synergize as vaccine adjuvant to enhance immune responses in mice by induction of early interleukin‐15 but not interleukin‐1β responses

Abstract

Vitamins A and E and select flavonoids in the family of catechins are well-defined small molecules that, if proven to possess immunomodulatory properties, hold promise as vaccine adjuvants and various therapies. In an effort to determine the in vivo immunomodulatory properties of these molecules, we found that although mucosal and systemic vaccinations with a recombinant HIV-1 BaL gp120 with either a catechin, epigallo catechin gallate (EGCG) or pro-vitamin A (retinyl palmitate) alone in a vegetable-oil-in-water emulsion (OWE) suppressed antigen-specific responses, the combination of EGCG and vitamin A or E in OWE (Nutritive Immune-enhancing Delivery System, NIDS) synergistically enhanced adaptive B-cell, and CD4 + and CD8 + T-cell responses, following induction of relatively low local and systemic innate tumour necrosis factor-a (TNFa), interleukin-6 (IL-6) and IL-17, but relatively high levels of early systemic IL-15 responses. For induction of adaptive interferon-c and TNF-a responses by CD4 + and CD8 + T cells, the adjuvant effect of NIDS was dependent on both IL-15 and its receptor. In addition, the anti-oxidant activity of NIDS correlated positively with higher expression of the superoxide dismutase 1, an enzyme involved in reactive oxygen species elimination but negatively with secretion of IL-1b. This suggests that the mechanism of action of NIDS is dependent on anti-oxidant activity and IL-15, but independent of IL-1b and inflammasome formation. These data show that this approach in nutritive vaccine adjuvant design holds promise for the development of potentially safer effective vaccines.

Early IgG Response to Foot and Mouth Disease Vaccine Formulated with a Vegetable Oil Adjuvant

“…Similarly, in the present study, supplementation of GS in SO has been found to increase antibody responses 2 weeks after the booster immunization. VE has been reported to exert immunostimulatory activities as an adjuvant to various vaccines and formulated in AS03 [15][16][17][18]. The present study found similar results that addition of VE in SO increased IgG1 numerically and IgG2a significantly.…”

Enhanced Immune Responses with Serum Proteomic Analysis of Hu Sheep to Foot-and-Mouth Disease Vaccine Emulsified in a Vegetable Oil Adjuvant

“…Our previous study demonstrated that a vegetable oil containing both vitamin E and ginseng saponins (SO-VE-GS) had adjuvant effect and significantly improved the immune response induced with an FMD vaccine in mice [ 32 ]. VE included in vaccines to improve the immunostimulation has been reported in other studies [ 33 , 34 ]. Morel et al found that VE was required for an adjuvant AS03 to achieve the enhanced antibody response [ 33 ].…”

<b>Citrulline as a novel adjuvant candidate for </b><b>vaccines</b>

“…Unlike arginine, citrulline is known to have antioxidant activity (1). It was reported that some compounds with antioxidant activity have immunomodulatory effects although the modes of action remain unclear (7,23,27,29). When modified M2e and amyloid β peptides were used as antigens, citrulline showed much higher adjuvant activity than that of the other vaccine antigens used in this study.…”