A recently discovered enzyme system produces antibacterial hypothiocyanite (OSCN − ) in the airway lumen by oxidizing the secreted precursor thiocyanate (SCN − ). Airway epithelial cultures have been shown to secrete SCN − in a CFTR-dependent manner. Thus, reduced SCN − availability in the airway might contribute to the pathogenesis of cystic fibrosis (CF), a disease caused by mutations in the CFTR gene and characterized by an airway host defense defect. We tested this hypothesis by analyzing the SCN − concentration in the nasal airway surface liquid (ASL) of CF patients and non-CF subjects, and in the tracheobronchial ASL of CFTR-ΔF508 homozygous pigs and control littermates. In the nasal ASL, the SCN − concentration was ~30-fold higher than in

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Ras expression in human epithelial cells with integrated HPV genomes has been shown to cause tumorigenic transformation. The effects of Ras in cells representing early stage HPV-associated disease (i.e., when HPV is extrachromosomal and the oncogenes are under control of native promoters) have not been examined. Here, we used human cervical keratinocyte cell lines containing stably replicating extrachromosomal HPV-16 and present the novel finding that these cells resist transformation by oncogenic H-Ras. Ras expression consistently diminished anchorage-independent growth (AI), reduced E6 and E7 expression, and caused p53 induction in these cells. Conversely, AI was enhanced or maintained in Ras-transduced cervical cells that were immortalized with a 16E6/E7 retrovirus, and minimal effects on E6 and E7 expression were observed. Ras expression with either episomal HPV-16 or LXSN-E6/E7 was insufficient for tumorigenic growth suggesting that other events are needed for tumorigenic transformation. In conclusion, our results indicate that Ras-mediated transformation depends on the context of HPV oncogene expression and that this is an important point to address when developing HPV tumor models.

Adjuvants modulate protective CD8+ T cell responses generated by cancer vaccines. We have previously shown that immunostimulatory CpG ODN significantly augments tumor protection in mice given adenovirus cancer vaccines. Here, we examined the impact of chitosan, another candidate vaccine adjuvant, on protection conferred by adenovirus cancer vaccines. Unexpectedly, immunization of mice with adenovirus cancer vaccines in combination with chitosan provided little protection against tumor challenge. This directly correlated with reduced detection of Ag-specific CD8+ T cells, IFN-γ production and cytotoxic T cell activity. We ruled out immunosuppressive regulatory T cells since frequency did not change regardless of whether chitosan was delivered. In mammalian cell lines, chitosan did not interfere with adenovirus transgene expression. However, infection of primary murine bone marrow-derived dendritic cells with adenovirus complexed with chitosan significantly reduced viability, transgene expression and upregulation of MHC class I and CD86. Our in vitro observations indicate that chitosan dramatically inhibits adenovirus-mediated transgene expression and antigen presenting cell activation, without which CD8+ T cell activation cannot occur in vivo. These surprising data demonstrate for the first time that chitosan vaccine formulations can negatively impact the induction of CD8+ T cell responses via its effect on dendritic cells, which is clinically important since consideration of chitosan as an adjuvant for vaccine formulations is growing.