Potential Roles of CCR5+ CCR6+ Dendritic Cells Induced by Nasal Ovalbumin plus Flt3 Ligand Expressing Adenovirus for Mucosal IgA Responses

We assessed the role of CCR5(+)/CCR6(+)/CD11b(+)/CD11c(+) dendritic cells (DCs) for induction of ovalbumin (OVA)-specific antibody (Ab) responses following mucosal immunization. Mice given nasal OVA plus an adenovirus expressing Flt3 ligand (Ad-FL) showed early expansion of CCR5(+)/CCR6(+)/CD11b(+)/CD11c(+) DCs in nasopharyngeal-associated lymphoid tissue (NALT) and cervical lymph nodes (CLNs). Subsequently, this DC subset became resident in submandibular glands (SMGs) and nasal passages (NPs) in response to high levels of CCR-ligands produced in these tissues. CD11b(+)/CD11c(+) DCs were markedly decreased in both CCR5(-/-) and CCR6(-/-) mice. Chimera mice reconstituted with bone marrow cells from CD11c-diphtheria toxin receptor (CD11c-DTR) and CCR5(-/-) or CD11c-DTR and CCR6(-/-) mice given nasal OVA plus Ad-FL had elevated plasma IgG, but reduced IgA as well as low anti-OVA secretory IgA (SIgA )Ab responses in saliva and nasal washes. These results suggest that CCR5(+)CCR6(+) DCs play an important role in the induction of Ag-specific SIgA Ab responses.