Glycans from avian influenza virus are recognized by chicken dendritic cells and are targets for the humoral immune response in chicken

To increase our understanding of the interaction between avian influenza virus and its chicken host, we identified receptors for putative avian influenza virus (AIV) glycan determinants on chicken dendritic cells. Chicken dendritic cells (DCs) were found to recognize glycan determinants containing terminal alpha GalNAc, Gal alpha 1-3Gal, GlcNAc beta 1-4GlcNAc beta 1-4GlcNAc beta (chitotriose) and Gal alpha 1-2Gal. Infection of chicken dendritic cells with either low pathogenic (LP) or highly pathogenic (HP) AIV results in elevated mRNA expression of homologs of the mouse C-type lectins DEC205 and macrophage mannose receptor (MMR), whereas expression levels of the human dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) homolog remained unchanged. Following uptake and subsequent presentation of avian influenza virus by DCs, adaptive immunity, including humoral immune responses are induced. We have investigated the antibody responses against virus glycan epitopes after avian influenza virus infection. Using glycan micro-array analysis we showed that chicken contained antibodies that predominantly recognize terminal Gal alpha 1-3Gal-R, chitotriose and Fuc alpha 1-2Gal beta 1-4GlcNAc-R (H-type 2). After influenza-infection, glycan array analysis showed that both levels and repertoire of glycan-recognizing antibodies decreased. However, analysis of the sera by ELISA indicated that the levels of different isotypes of anti-glycan Abs against specific glycan antigens was increased after influenza-infection, suggesting that the presentation of the glycan antigens and iso-type of the Abs are critical parameters to take into account when measuring anti-glycan Abs. This novel approach in avian influenza research may contribute to the development of a broad spectrum vaccine and improves our mechanistic understanding of innate and adaptive responses to glycans. (C) 2013 Elsevier Ltd. All rights reserved.