In vivo tracking of rhesus macaque eosinophils to assess migration in response to glucocorticoids

Abstract

RATIONALE:We have developed an oil-in-water based nanoemulsion (NE) that induces strong systemic and mucosal immunity against a variety of pathogens when used as a mucosal adjuvant. In an effort to enhance the mucosal immune responses of NE, we co-formulated it with retinoic acid (NERA). RA, a vitamin A derivative, has been shown to orchestrate T cell homing towards the gut as well as IgA production by retinaldehyde dehydrogenase (RALDH) in dendritic cells (DCs). METHODS: To examine the efficacy of NERA in-vitro, we simulated invivo intranasal immunization in a co-culture model. We treated the epithelial cells with different formulations of NE, followed by co-culturing with dendritic and T cells. Further, animals were intranasally immunized with ova-albumin (Ova) in combination to NE (with and without RA) to study RALDH production by mucosal DCs, T cell gut homing, IgA production and Th1/Th2/Th17 cytokine production. RESULTS: NE alone induces RALDH activity in co-cultured DCs and induces gut homing marker expression in-vitro. Also, immunization with NE-Ova showed increased RALDH activity in DCs, resulting in increased IgA production as well as T cell gut homing. Furthermore, antibody titers and cytokine data suggested increased Th1/Th17 response while suppressing Th2. In-vitro studies showed NE activates RALDH partially via Abstracts AB191 SUNDAY