title: Oral intake of Lactobacillus rhamnosus M21 enhances the survival rate of mice lethally infected with influenza virus.
abstract: BACKGROUND
  Influenza viruses cause acute respiratory disease. Because of the high genetic variability of viruses, effective vaccines and antiviral agents are limited. Considering the fact that the site of influenza virus entry is the mucosa of the upper respiratory tract, probiotics that can enhance mucosal immunity as well as systemic immunity could be an important source of treatment against influenza infection.
  
  
  METHODS
  Mice were fed with Lactobacillus rhamnosus M21 or skim milk and were challenged with influenza virus. The resulting survival rate, lung inflammation, and changes in the cytokine and secretory immunoglobulin A (sIgA) levels were examined.
  
  
  RESULTS
  Because of infection (influenza virus), all the mice in the control group and 60% of the mice in the L. rhamnosus M21 group died; however, the remaining 40% of the mice fed with L. rhamnosus M21 survived the infection. Pneumonia was severe in the control group but moderate in the group treated with L. rhamnosus M21. Although there were no significant changes in the proinflammatory cytokines in the lung lysates of mice collected from both groups, levels of interferon-γ and interleukin-2, which are representative cytokines of type I helper T cells, were significantly increased in the L. rhamnosus M21-treated group. An increase in sIgA as well as the diminution of inflammatory cells in bronchoalveolar lavage fluid was also observed in the L. rhamnosus M21-treated group.
  
  
  CONCLUSIONS
  These results demonstrate that orally administered L. rhamnosus M21 activates humoral as well as cellular immune responses, conferring increased resistance to the host against influenza virus infection.
authors.affiliation: Department of Veterinary Immunology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea; Inhalation Toxicology Center, KIT Jeongeup Campus, 1051, Shinjeong-dong, Jeongeup, 580-185, Republic of Korea.
authors.forename: Jeong Ah
authors.initials: JA
authors.lastname: Song
authors.affiliation: Department of Veterinary Immunology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea.
authors.forename: Hee Joo
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Veterinary Immunology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea.
authors.forename: Seong Keun
authors.initials: SK
authors.lastname: Hong
authors.affiliation: Department of Veterinary Immunology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea.
authors.forename: Dong Hoon
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Veterinary Immunology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Veterinary Immunology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea.
authors.forename: Chang Seon
authors.initials: CS
authors.lastname: Song
authors.affiliation: M21 Company Limited, 649-27 Samjon-ri, Songsan-myeon, Hwaseong-si, Kyungki-do, 445-871, Republic of Korea.
authors.forename: Ki Taek
authors.initials: KT
authors.lastname: Kim
authors.affiliation: Department of Veterinary Immunology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea.
authors.forename: In Soo
authors.initials: IS
authors.lastname: Choi
authors.affiliation: Department of Veterinary Immunology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea.
authors.forename: Joong Bok
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Department of Veterinary Immunology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea. Electronic address: paseyo@konkuk.ac.kr.
authors.forename: Seung Yong
authors.initials: SY
authors.lastname: Park
mesh_terms: D000284:Administration, Oral; D000818:Animals; D016207:Cytokines / Q000032:analysis; D060467:Disease Resistance; D005260:Female; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D052201:Lacticaseibacillus rhamnosus / Q000276:immunology*; D008168:Lung / Q000473:pathology; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000473:pathology* / Q000517:prevention & control*; D019936:Probiotics / Q000008:administration & dosage*; D015996:Survival Rate
chemical_list: D016207:Cytokines; D007071:Immunoglobulin A, Secretory
keywords: cytokines; immunoglobulin A; influenza; lung infection; probiotics