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Rhinovirus species C (RV-C) causes more severe asthma attacks than other rhinovirus species. However, the modulation of RV-C replication by drugs has not been well studied. Primary human nasal epithelial (HNE) cells cultured on filter membranes with air-liquid interface methods were infected with RV-C03, and the levels of RV-C03 RNA collected from the airway surface liquid (ASL) of HNE cells were measured with a SYBR Green assay. Pretreatment of HNE cells with the specific vacuolar H

Summary Rhinovirus species C (RV-C) causes more severe asthma attacks than other rhinovirus species. However, the modulation of RV-C replication by drugs has not been well studied. Primary human nasal epithelial (HNE) cells cultured on filter membranes with air-liquid interface methods were infected with RV-C03, and the levels of RV-C03 RNA collected from the airway surface liquid (ASL) of HNE cells were measured with a SYBR Green assay. Pretreatment of HNE cells with the specific vacuolar H+-ATPase inhibitor bafilomycin A1 reduced the RV-C03 RNA levels in the ASL; inflammatory cytokines, including interleukin (IL)-1β, IL-6 and IL-8, in the supernatant; the mRNA expression of the RV-C receptor cadherin-related family member 3 (CDHR3) in the cells; and the number of acidic endosomes where RV-B RNA enters the cytoplasm. The levels of RV-C03 RNA in the ASL obtained from HNE cells with the CDHR3 rs6967,330 G/A genotype tended to be higher than those obtained from HNE cells with the G/G genotype. Pretreatment with the Na+/H+ exchanger inhibitor ethyl-isopropyl amiloride or either of the macrolides clarithromycin or EM900 also reduced RV-C03 RNA levels in the ASL and the number of acidic endosomes in HNE cells. In addition, significant levels of RV-A16, RV-B14 and RV-C25 RNA were detected in the ASL, and bafilomycin A1 also decreased the RV-C25 RNA levels. These findings suggest that bafilomycin A1 may reduce the release of RV-Cs and inflammatory cytokines from human airway epithelial cells. RV-Cs may be sensitive to drugs, including bafilomycin A1, that increase endosomal pH, and CDHR3 may mediate virus entry through receptor-mediated endocytosis in human airway epithelial cells.

Seven hexon hypervariable regions (HVRs) of adenoviruses (Ads) were identified by comparing the regions among different serotypes; however, no one has compared HVR sequences among the identical serotypes, except for adenovirus type 3 (Ad3). To examine a variability between the HVRs for each serotype, we compared the sequences of Ad1-6 isolates, respectively, isolated between 1988 and 2007 in Yamagata, Japan. We selected 23-43 isolates randomly and sequenced 894-987 bp regions. Except for strains with insertions and deletions, the sequence identities among Ad1-6 were 99-100%, excluding that between the two Ad5 groups (approx. 94%). Even the insertions and deletions were likely to be established, as these changes were repeatedly observed. The obtained phylogenetic tree indicated that Ad isolates and reference strains branched depending on serotype. The Yamagata isolates had similar sequences or amino acid arrangements to the reference strains as well as to other strains isolated in different areas. HVRs have been stably conserved as serotype-specific regions for a long period with only minor genomic variations. Therefore, we herein recommend that these regions be hereafter referred to as "serotype-specific regions", which might be a more appropriate title with which to characterize the epidemiological nature of these sites than the current "HVRs".