Protection Against Respiratory Syncytial Virus Infection Induced Airway Hyperresponsiveness by DNA Encoding RSV-G Protein Immunization / 소아알레르기및호흡기학회지

ABSTRACT

PURPOSE: Respiratory syncytial virus is the primary cause of pneumonia and bronchiloitis in young children and infants. RSV infection is also known to be very important to asthma patient, because previous RSV infection increases the frequency of the asthma development and RSV infection may cause airway hyperresponsiveness. Natural RSV infection does not provide complete immunity and reinfection occurs throughout life. Several strategies have recently been used in RSV vaccine development, including the generation of formalin inactivated RSV(FI-RSV), peptides, recombinant vaccine viruses (rVV), and DNA based vaccines. Previous studies in mice primed with RSV G protein enhanced lung pathology resulted from a Th2 host immune response against the viral G protein. We studied for the evaluation of protective immunity, effect on airway hyperesponsiveness, and influence on lung pathology after pND G immunization. METHODS: BALB/c mice were injected with pND G(50g in 1 g/l PBS), pND G-HA (50 g), pND(50 g) FI-RSV(10 6PFU) i.d.at 0, 2, 4 weeks. Four weeks later, mice were challenged with RSV(10 6PFU). Mice were sacrificed on postchallenge day 4 and their lungs were removed for RT-PCR and viral titration. The other mice were sacrificed on postchallenge day 6 for bronchoalveolar lavage, serum and histologic examination. Airway responsiveness was assessed by using a single chamber whole body plethysmography on post challenge day 5. RESULTS: 1) Vaccination with pND-G reduced the Mch(methacholine) induced airway hyperresponsiveness after RSV infection(P0.05). CONCLUSION: In this study, immunization with pND encoding G protein induced decrease in airway hyperresponsiveness, and protection against RSV infection of the lower respiratory tract infection and also induced virus neutralizing antibody and decrease in lymphocytic inflammation. pND G immunization elicited balanced pulmonary Th1/Th2 cytokine response without atypical pulmonary inflammatory responses.