Immunogenicity and protective efficacy of orally or intranasally administered recombinant Lactobacillus casei expressing ETEC K99.
In an effort to develop a safe and effective vaccine for the prevention of enterotoxigenic Escherichia coli (ETEC) K99 infections, we have developed a surface antigen display system using pgsA (poly-gamma-glutamate synthetase A) as an anchoring matrix. The recombinant fusion proteins comprised of pgsA and fimbriae protein of ETEC K99 were stably expressed on Lactobacillus casei. Surface localization of the fusion protein was verified by immunoblotting, immunofluorescence microscopy and flow cytometry. Specific Pathogen Free (SPF) BALB/c mice orally or intranasally vaccinated with recombinant L. casei resulted in high levels of serum immunoglobulin G (IgG) and mucosal IgA against ETEC K99, as demonstrated by enzyme-linked immunosorbent assays using purified fimbriae peptides. The serum antibody isotypes elicited were predominantly IgG1 and IgG2a. Vaccinated SPF BALB/c mice were evaluated by oral challenge with standard-type ETEC C83912 after the last booster immunization. More than 80% of immunized mice survived regardless of the immune route. The antibody titers elicited following oral immunization were lower than those following intranasal immunization but the protective efficacy was in the same order of magnitude. These results indicate that mucosal immunization with recombinant L. casei expressing ETEC K99 fimbriae protein on its surface provides an effective means for eliciting a protective immune response against the ETEC K99.
Wei
Chun-Hua
CH
College of Animal Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province, 163319, China.
Liu
Jian-Kui
JK
Hou
Xi-Lin
XL
Yu
Li-Yun
LY
Lee
Jong-Soo
JS
Kim
Chul-Joong
CJ
D000281:Administration, Intranasal; D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D054307:Enterotoxigenic Escherichia coli / Q000276:immunology*; D004927:Escherichia coli Infections / Q000276:immunology / Q000517:prevention & control*; D029968:Escherichia coli Proteins / Q000276:immunology*; D022361:Escherichia coli Vaccines / Q000276:immunology*; D005260:Female; D018928:Immunity, Mucosal; D007071:Immunoglobulin A, Secretory / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D007780:Lacticaseibacillus casei / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins / Q000276:immunology; D013047:Specific Pathogen-Free Organisms; D014157:Transcription Factors / Q000276:immunology*
D000907:Antibodies, Bacterial; D029968:Escherichia coli Proteins; D022361:Escherichia coli Vaccines; C107308:FanB protein, E coli; D007071:Immunoglobulin A, Secretory; D007074:Immunoglobulin G; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors