Microparticulate beta-glucan vaccine conjugates phagocytized by dendritic cells activate both naive CD4 and CD8 T cells in vitro

Abstract

Microparticulate beta-glucan (MG) conjugated to vaccine antigen has been shown to serve as an effective adjuvant in vivo. To further study antigen presentation by MG: vaccine conjugates, bone marrow-derived dendritic cells (BMDC) were treated with MG conjugated to ovalbumin (OVA), then interacted with splenocytes from DO11.10 transgenic mice expressing an OVA peptide-specific T cell receptor. BMDC treated with MG: OVA induced significantly higher numbers of activated (CD25+CD69+) OVA-specific CD4+ T cells than BMDC treated with OVA alone. BMDC treated with MG: OVA upregulated CD86 and CD40 expression as well as MG alone, indicating that conjugation of OVA does not alter the immunostimulatory capacity of MG. Activation of CD8+ OVA-specific OT-1 cells showed that MG: OVA is also capable of enhancing cross-presentation by BMDC to CD8+ cytotoxic T cells. These results show that MG acts as an adjuvant to enhance antigen presentation by dendritic cells to naive, antigen-specific CD4 and CD8 T cells. (C) 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).