title: Lactobacillus acidophilus CP23 with weak immunomodulatory activity lacks anchoring structure for surface layer protein.
abstract: To determine the reason for the low levels of Surface layer protein A (SlpA) on CP23 cells, which might play a crucial role in the immunomodulatory effect of Lactobacillus acidophilus, the DNA sequence of the slpA gene of CP23 and L-92 strains, including the upstream region, were analyzed. Unexpectedly, there was no significant difference in the predicted amino acid sequence of the C-terminus needed for cell anchoring, and only an additional Ala-Val-Ala sequence inserted in the N-terminal region of the mature CP23 protein. Therefore, anchoring of SlpA on the cell wall of CP23 and L-92 was evaluated by a reconstitution assay, which showed that SlpA released by LiCl treatment from both CP23 and L-92 was successfully anchored on LiCl-treated L-92 cells, but not on LiCl-treated CP23 cells. Moreover, quantitative analysis of SlpA protein in the culture medium of CP23 and L-92 by ELISA revealed higher levels of SlpA secretion in CP23 cells than in L-92 cells. Collectively, these results suggest that the lower levels of SlpA on the surface of CP23 cells might be caused by less cell wall capacity for SlpA anchoring, leading to an accumulation of SlpA in the culture medium of CP23 cells. The present study supports the importance of cell surface structure of L. acidophilus L-92 for SlpA anchoring on the cell surface needed for immunomodulatory effect.
authors.affiliation: Microbiology and Fermentation Laboratory, Calpis Co. Ltd., 5-11-10 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-0206, Japan. Electronic address: sae.yanagihara@calpis.co.jp.
authors.forename: Sae
authors.initials: S
authors.lastname: Yanagihara
authors.affiliation: Microbiology and Fermentation Laboratory, Calpis Co. Ltd., 5-11-10 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-0206, Japan. Electronic address: Shinji.kato@calpis.co.jp.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kato
authors.affiliation: Feed Technology Group Feed Division, Calpis Co. Ltd., 5-11-10 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-0206, Japan. Electronic address: nobuhisa.ashida@calpis.co.jp.
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Ashida
authors.affiliation: Research and Development Planning Department, Calpis Co. Ltd., 5-11-10 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-0206, Japan. Electronic address: naoyuki.yamamoto@calpis.co.jp.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Yamamoto
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism*; D002473:Cell Wall / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism; D007779:Lactobacillus acidophilus / Q000737:chemistry* / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D018021:Lithium Chloride / Q000494:pharmacology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D003470:Culture Media; C070683:surface layer protein A, Bacteria; D018021:Lithium Chloride
keywords: Cell surface anchoring; Lactobacillus acidophilus; LiCl treatment; Reconstitution assay; Surface layer protein A; slpA gene sequence