Impact on antigen­specific IgA antibody immune responses by nasal administration with hinokitiol

Abstract

We investigated whether mucosal and systemic antigen (Ag)­specific immune re­ sponses were induced by nasal administration of synthetic hinokitiol (HNK). Mice in the experi­ mental groups were immunized under anesthesia three times at weekly intervals nasally with 100 μg of chicken ovalbumin (OVA) and 5 μg or 50 μg of HNK simultaneously. As a negative control, mice were given nasally 100 μg of OVA alone, and as a positive control, they were ad­ ministered nasally 100 μg of OVA and 50 μg of DNA plasmid expressing Flt3 ligand (pdF3L) as a mucosal adjuvant. Saliva, nasal washes (NWs), and plasma were collected on days 0, 7, 14 and 21, and we determined the Ag­specific IgA antibodies (Abs) in each sample by Ag­specific ELISA methods. In addition, mononuclear cells from submandibular glands (SMG), nasal pas­ sages (NPs), nasopharyngeal­associated lymphoreticular tissues (NALT), cervical lymph nodes and spleen were supplied to antigen­specific ELISPOT assay in order to examine induction of OVA­specific IgA Ab­forming cells. Consequently, we found little induction of systemic or mu­ cosal IgA immune responses, compared with the positive control. These results suggest that HNK does not bear a mucosal adjuvanticity to provoke Ag­specific IgA immune responses. Shika Igaku (J Osaka Odontol Soc) 2018 ;Mar ;81(1) : 16­-23.