title: Soluble RANKL expression in Lactococcus lactis and investigation of its potential as an oral vaccine adjuvant.
abstract: BACKGROUND
  To initiate mucosal immune responses, antigens in the intestinal lumen must be transported into gut-associated lymphoid tissue through M cells. Recently, it has been increasingly recognized that receptor activator of NF-kB ligand (RANKL) controls M cell differentiation by interacting with RANK expressed on the sub-epithelium of Peyer's patches. In this study, we increased the number of M cells using soluble RANKL (sRANKL) as a potent mucosal adjuvant.
  
  
  RESULTS
  For efficient oral delivery of sRANKL, we constructed recombinant Lactococcus lactis (L. lactis) IL1403 secreting sRANKL (sRANKL-LAB). The biological activity of recombinant sRANKL was confirmed by observing RANK-RANKL signaling in vitro. M cell development in response to oral administration of recombinant L. lactis was determined by 1.51-fold higher immunohistochemical expression of M cell marker GP-2, compared to that of non-treatment group. In addition, an adjuvant effect of sRANKL was examined by immunization of mice with M-BmpB as a model antigen after treatment with sRANKL-LAB. Compared with the wild-type L. lactis group, the sRANKL-LAB group showed significantly increased systemic and mucosal immune responses specific to M-BmpB.
  
  
  CONCLUSIONS
  Our results show that the M cell development by sRANKL-LAB can increase the antigen transcytotic capability of follicle-associated epithelium, and thereby enhance the mucosal immune response, which implies that oral administration of sRANKL is a promising adjuvant strategy for efficient oral vaccination.
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. galein0525@naver.com.
authors.forename: Jeong-In
authors.initials: JI
authors.lastname: Kim
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. shakewh8@snu.ac.kr.
authors.forename: Tae-Eun
authors.initials: TE
authors.lastname: Park
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. ruma_sushila@hotmail.com.
authors.forename: Sushila
authors.initials: S
authors.lastname: Maharjan
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. smallgirlfan@naver.com.
authors.forename: Hui-Shan
authors.initials: HS
authors.lastname: Li
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. yoyo5064@naver.com.
authors.forename: Ho-Bin
authors.initials: HB
authors.lastname: Lee
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. is719@naver.com.
authors.forename: In-Seon
authors.initials: IS
authors.lastname: Kim
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. win_2008@hanmail.net.
authors.forename: Dachuan
authors.initials: D
authors.lastname: Piao
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. akirus86@snu.ac.kr.
authors.forename: Jun-Yeong
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. chocs@snu.ac.kr.
authors.forename: Chong-Su
authors.initials: CS
authors.lastname: Cho
authors.affiliation: Institute of Green-Bio Science & Technology, Seoul National University, Pyeongchanggun, Gangwondo, South Korea. jdbok@snu.ac.kr.
authors.forename: Jin-Duck
authors.initials: JD
authors.lastname: Bok
authors.affiliation: Department of Animal Science, Tianjin Agricultural University, Tianjin, China. hzs019@163.com.
authors.forename: Zhong-Shan
authors.initials: ZS
authors.lastname: Hong
authors.affiliation: Institute of Green-Bio Science & Technology, Seoul National University, Pyeongchanggun, Gangwondo, South Korea. kangsk01@snu.ac.kr.
authors.forename: Sang-Kee
authors.initials: SK
authors.lastname: Kang
authors.affiliation: Department of Agricultural Biotechnology & Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea. cyjcow@snu.ac.kr.|Department of Animal Science, Tianjin Agricultural University, Tianjin, China. cyjcow@snu.ac.kr.
authors.forename: Yun-Jaie
authors.initials: YJ
authors.lastname: Choi
mesh_terms: D000276:Adjuvants, Immunologic; D000284:Administration, Oral; D000818:Animals; D015870:Gene Expression; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D013294:Lactococcus lactis / Q000235:genetics*; D051379:Mice; D010581:Peyer's Patches / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D053245:RANK Ligand / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014612:Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D053245:RANK Ligand; D011994:Recombinant Proteins; D014612:Vaccines