Background: Although some studies in the southeast part of Guizhou Province have suggested that Miaoyao Fanggan sachets (MFS) prevent influenza, little is known about its influence on immune systems. Influenza virus mainly infects immune-compromised individuals. The effects of MFS have mainly been recognized in clinical practice. However, there have been relatively few studies on its biological mechanism. Here we investigated whether MFS was able to affect the mucosal immunization and the activation of alveolar macrophages (AM), CD4+and CD8+ T-cells in vivo.
Methods: Eighty Kunming male mice were treated with MFS continuously or intermittently with Yu-Ping-Feng powder (YPF-P) (positive control group) or with normal saline (NS) (control group) for 4 weeks, respectively. Mice treated with MFS were further divided into the continuous inhalation group (12 h daily/4 weeks) and the discontinuous inhalation group (1 h, three times a day for 4 weeks). Mice in both groups were placed under 0.5 m3 masks which had four ventilation holes (10×15 cm) containing 40 g MFS. Positive control mice were orally treated with YPF-P 0.2 mg/10 g/day once a day for 4 weeks. Control mice were orally treated with equal volumes of NS once a day for 4 weeks. MFS was replaced every 6 days. Administration of YPF-P was used as a positive control since it has been used as an established Traditional Chinese Medicine (TCM) treatment before. After 4 weeks, mice in all experimental groups were sacrificed. IgA and IgG1 in lung and blood serum were detected by Western blot and enzyme-linked immuno sorbent assay (ELISA). The expression of alveolar macrophages (AM) in mice was analyzed by immunochemistry test based on CD68+staining. Blood samples were collected in which CD4+and CD8+T-cells were analyzed by flow cytometry.
Results: Mice continuously and intermittently inhaling MFS showed a moderate increase in IgA and IgG1 protein levels compared with mice in the control groups. There was also a slightly significant increase in the number of AM in the continuous inhalation group compared with mice in the control groups (p<0.05). Furthermore, compared with controls, there was also a slightly significant increase in the number and percentage of CD4+and CD8+T-cells in both the continuous inhalation group and the discontinuous inhalation group (p<0.05).
Conclusions: MFS was able to up-regulate the protein levels of sIgA and IgG1. Meanwhile, MFS could activate AM, CD4+and CD8+T-cells in mice. Our data have, for the first time, demonstrated that the protection against influenza by MFS is partly through activation of the innate and adaptive cell-mediated immune responses, indicating MFS as a potential new immune-modulatory agent for respiratory tract infectious disease.