Nasal Immunization with Anthrax Protective Antigen Protein Adjuvanted with Polyriboinosinic–Polyribocytidylic Acid Induced Strong Mucosal and Systemic Immunities

Purpose The current anthrax vaccine adsorbed (AVA) was originally licensed for the prevention of cutaneous anthrax infection. It has many drawbacks, including the requirement for multiple injections and subsequent annual boosters. Thus, an easily administrable and efficacious anthrax vaccine is needed to prevent the most lethal form of anthrax infection, inhalation anthrax. We propose to develop a nasal anthrax vaccine using anthrax protective antigen (PA) protein as the antigen and synthetic double-stranded RNA in the form of polyriboinosinic–polyribocytidylic acid (pI:C) as an adjuvant. Methods Mice were nasally immunized with recombinant PA admixed with pI:C. The resulting PA-specific antibody responses and the lethal toxin neutralization activity were measured. Moreover, the effect of pI:C on dendritic cells (DCs) was evaluated both in vivo and in vitro. Results Mice nasally immunized with rPA adjuvanted with pI:C developed strong systemic and mucosal anti-PA responses with lethal toxin neutralization activity. These immune responses compared favorably to that induced by nasal immunization with rPA adjuvanted with cholera toxin. Poly(I:C) enhanced the proportion of DCs in local draining lymph nodes and stimulated DC maturation. Conclusions This pI:C-adjuvanted rPA vaccine has the potential to be developed into an efficacious nasal anthrax vaccine.     

Protein Oxidation and DNA–Protein Crosslink Induced by Sulfur Dioxide in Lungs,Livers, and Hearts from Mice

In this article, protein oxidative damage and DNA–protein crosslinks (DPC) induced by sulfur dioxide (SO₂) in lungs, livers, and hearts of mice were studied. The protein carbonyl (PCO) content was measured using spectrophotometric DNPH assay to reflect the degree of protein oxidative damage, and the DPC coefficient was measured by using a KCl–sodium dodecyl sulfate (SDS) assay to show the degree of DNA damage in lungs, livers, and hearts from mice exposed to SO₂ at various concentrations (0, 14, 28, and 56 mg-m^{? 3}) for 6 h per day for 7 days. The results indicate that SO₂ caused an increase of PCO and DPC level in all organs tested from mice in a concentration-dependent manner. The concentration-response relationships in all organs tested of both female and male mice could be fitted well with monolinear regression equations. The adjusted coefficient R squared of all equations is more than 0.9. These results lead to a conclusion that SO₂ may cause an increase of protein oxidation damage and DNA–protein crosslinking in lungs, livers, and hearts from mice. The rank order of absolute increase in PCO contents and DPC coefficient in three organs from mice compared with controls was lung > liver > heart. Our results also indicated the regulation of PCO and that of DPC induced by SO₂ were conformed to each other; this implies that the protein oxidative damage may be associated with the emergence of DPC.