title: Oral administration of heat-killedLactobacillus kunkeeiYB38 improves murine influenza pneumonia by enhancing IgA production.
abstract: Influenza is one of the important respiratory tract infections that require special attention for maintaining health and hygiene. The removal of influenza virus (IFV) by secretory IgA produced by the respiratory epithelium has been reported to be a critical host defense mechanism. Therefore, we isolatedLactobacillus kunkeeiYB38 (YB38), the promoter of the salivary IgA secretion in humans, from honeybee pollen and studied the effect of heat-killed YB38 treatment for preventing IFV infection in a mouse model. Female BALB/c mice received YB38 orally for 21 consecutive days and were then inoculated nasally with IFV. The YB38-treated group with a daily dose of 100 mg/kg showed an increased survival rate after IFV infection relative to the control. IgA secretion in the respiratory epithelium in the YB38-treated group (100 mg/kg) was significantly increased after 6 days of infection, while IL-6 production in the same respiratory site and the number of cells infiltrating into alveoli were significantly decreased. Moreover, lung tissue damage that appeared after IFV infection was reduced. These results suggested that the YB38 dose induced early and local IgA secretion at the infection site, inhibited persistent IFV infection, and prevented the infiltration of inflammatory immune cells or production of excessive IL-6, resulting in less damage to lung tissues.
authors.affiliation: Institute for Bee Products and Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino-cho, Tomata-gun, Okayama 708-0393, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Asama
authors.affiliation: Biomedical Laboratory, Division of Biomedical Research, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama 364-8501, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Uematsu
authors.affiliation: Biomedical Laboratory, Division of Biomedical Research, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama 364-8501, Japan.
authors.forename: Noritada
authors.initials: N
authors.lastname: Kobayashi
authors.affiliation: Institute for Bee Products and Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino-cho, Tomata-gun, Okayama 708-0393, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Tatefuji
authors.affiliation: Institute for Bee Products and Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino-cho, Tomata-gun, Okayama 708-0393, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Hashimoto
keywords: Lactobacillus kunkeei YB38; immunoglobulin A; influenza virus; mice