Antiviral effects of modified dingchuan decoction against respiratory syncytial virus infection in vitro and in an immunosuppressive mouse model.

ETHNOPHARMACOLOGICAL RELEVANCE: Modified dingchuan decoction (MDD) is used in traditional Chinese medicine for the treatment of cough, chronic bronchitis, asthma and viral pneumonia. AIM OF THE STUDY: To investigate antiviral potentials of MDD in respiratory syncytial virus (RSV) infected mice. MATERIALS AND METHODS: MDD and each component were evaluated for antiviral efficacy against RSV in vitro in cell culture. Mice were were treated with cyclophosphamide and infected with RSV. Then, treatments with MDD at doses of 1.75 g/kg, 3.5 g/kg and 7.0 g/kg, respectively, were oral administrated daily for 5 days after challenge. The levels of Eotaxin, IL-4 and IFN-γ in serum and lung tissue were detected by ELISA, viral loads in lung tissues were detected by RFQ-PCR while expressions of NF-κB and TLR4 mRNA were also detected by RFQ-PCR. RESULTS: A selective index of >36.8 (2.5 times greater than that observed for ribavirin) was determined in the in vitro studies for this herbal medicine. MDD exhibited significant antiviral and anti-inflammatory effects on decreasing levels of Eotaxin, IL-4 and IFN-γ in serum and lung tissue, inhibiting pneumonia, decreasing lung viral loads and reversaling RSV-induced inflammation through down-regulation of TLR4 and NF-κB mRNA expression in the lung tissue of RSV-infected mice. CONCLUSIONS: MDD could exhibit antiviral and anti-inflammatory effects on RSV-infected mice as a suppressor of Eotaxin, IL-4 and IFN-γ. These effects appeared to be mediated by inhibitions of TLR4 and NF-κB activation. Therefore, MDD could provide an effective therapeutic approach for RSV and its subsequent viral bronchitis.

Attenuated interleukin-8/leukocyte immunoresponse in preterm infants compared with term infants hospitalized with respiratory syncytial virus bronchiolitis: a pilot study.

Decreased transplacental transfer of antibodies and altered immunoresponsiveness may place preterm (PT) infants at higher risk for serious consequences from respiratory syncytial virus (RSV) bronchiolitis. We hypothesize that among infants hospitalized with RSV bronchiolitis, immune response in PT infants may be different when compared with that of term infants. Nasal-wash samples were collected from 11 PT (<37 weeks of gestation) and 13 term infants (≥37 weeks of gestation) hospitalized with RSV bronchiolitis. Severity of illness (clinical score [CS]), admission peripheral oxygen saturation, and days subjects required supplemental oxygen were compared. Nasal-wash leukocyte count as well as cytokines for interleukin (IL)-8, IL-4, and interferon-γ (IFN-γ) were assayed. No significant differences in CS, admission SaO(2), and O(2) days were seen between PT and term infants. Nasal-wash leukocyte counts and IL-8 levels were higher in term infants compared with PT and correlated with severity (higher CS) in term (p < 0.05) but not in PT (p > 0.05) infants. IL-4 and IFN-γ levels did not differ between the 2 groups (p > 0.05). PT infants hospitalized with RSV bronchiolitis have lower nasal-wash leukocyte counts and a less robust IL-8 response than term infants, and only in term infants did IL-8 levels correlate with clinical disease severity.