The Effect Of Treatment With Dermatophagoides Farinae Vaccine On Der F Allergen-induced Allergic Airway Inflammation

OBJACTIVE: The aim of the present study is to investigate the efficacy and mechanism of standard Dermatophagoides farinae (Der f) nasal vaccine in a mouse asthma model induced by Der f allergen. Thus to provide a basis for the research, development and industrulization of standard Der f nasal vaccine.METHODS:1. 21 female Balb/c mice were randomly divided into 3 groups:Normal control group (group A),Model control group (group B), standard Der f nasal vaccine group (group C).The normal control group was treated with saline all along. Other groups were sensitized intraperitoneally with Der f allergen and immuned nasally with corresponding reagents.2. 21 female Balb/c mice were randomly divided into four groups:normal control group (group A),model control group (group B),standard Der f nasal vaccine group (group C) The normal control group was treated with saline all along. Other groups were sensitized intraperitoneally with Der f allergen,then immuned nasally with corresponding reagents,and finally challenged intranasally with Der f allergen. Twenty hours post challenge, airway hyper-reactvity (AHR) of mice was assayed. The lung inflammation was analyzed by haematoxylin and eosin (H&E) stain.The total cell numbers and composition of BALF samples were determined. The levels of the cytokines IL-10, IL-4 and IFN-γof BALF samples were determined using enzyme-linked immunosorbent assay (ELISA). The levels of Der f-specific IgE and IgG2a in the sera were determined by ELISA. The levels of IL-10, IL-4 and IFN-γproduced by spleen cells were also measured by ELISA. The spleen lymphocytes Der f-specific proliferation responses were analyzed by MTT colorimetry. The regulatory T cell numbers in spleen lymphocytes were assayed by flow cytometry.RESULTS:1. Mouse asthma model was successfully induced by Der f allergen.2. Standard Der f nasal vaccine inhibited AHR, extensive infiltration of inflammatory cells was induced by allergen. The influx of eosinophils into the lung interstitium was reduced significantly after administration of standard Der f nasal vaccine. Significant reductions in levels of IL-4 and increase in levels of IL-10 in BAL fluid were observed. The Der f-specific IgA was increased, and the Der f-specific IgG2a was markedly increased, while Der f -specific IgE was markedly decreased in mice receiving standard Der f nasal vaccine. Allergen could induce higher IL-10, weaker IL-4 in cultured spleen cells from mice receiving standard Der f nasal vaccine. Der f -specific proliferation of splenocyte was inhibited. Regulatory T cells were induced by standard Der f nasal vaccination.CONCLUSION:1. The sensitized Balb/c mice receiving standard Der f nasal vaccine induced IL-10 production and had increased Der f-specific Ig2a and IgA,but decreased allergen specific IgE antibody responses.2. Standard Der f nasal vaccine had immunotherapeutic effect on Der f allergen-induced allergic asthma, which indicated by reducing symptoms of asthma, the mechanism was involved with inducing regulatory T cells, IL-10 and Der f-specific Ig2a, thus inhibited Th2 reaction and Der f-specific IgE production.