Oral Administration of Recombinant Saccharomyces boulardii Expressing Ovalbumin-CPE Fusion Protein Induces Antibody Response in Mice

• Published in: Frontiers in microbiology Vol. 9; p. 723
• Main Authors: Bagherpour, Ghasem, Ghasemi, Hosnie, Zand, Bahare, Zarei, Najmeh, Roohvand, Farzin, Ardakani, Esmat M, Azizi, Mohammad, Khalaj, Vahid
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 13-04-2018
• Subjects: antigen delivery; Clostridium perfringens enterotoxin; Microbiology; mucosal immunity; recombinant ovalbumin; Saccharomyces boulardii; antigen delivery; Saccharomyces boulardii; Clostridium perfringens enterotoxin; recombinant ovalbumin; mucosal immunity
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2018.00723

, a subspecies of
, is a well-known eukaryotic probiotic with many benefits for human health. In the present study, a recombinant strain of
was prepared to use as a potential oral vaccine delivery vehicle. In this sense, a ura3 auxotroph strain of
CNCM I-745 (known as
HANSEN CBS 5926, Yomogi
) was generated using CRISPR/Cas9 methodology. Then a gene construct encoding a highly immunogenic protein, ovalbumin (OVA), was prepared and transformed into the
. To facilitate the transport of the recombinant immunogen across the intestinal barrier, a claudin-targeting sequence from
enterotoxin (CPE) was added to the C-terminus of the expression cassette. The recombinant
strain expressing the OVA-CPE fusion protein was then administered orally to a group of mice, and serum IgG and fecal IgA levels were evaluated by ELISA. Our results demonstrated that anti-OVA IgG in serum significantly increased in test group (
< 0.001) compared to control groups (receiving wild type
or PBS), and the fecal IgA titer was significantly higher in test group (
< 0.05) than control groups. In parallel, a recombinant
strain expressing the similar construct lacking C-terminal CPE was also administered orally. The result showed an increased level of serum IgG in group receiving yeasts expressing the CPE negative construct compared to control groups; however, the fecal IgA levels did not increase significantly. In conclusion, our findings indicated that the yeast
, as a delivery vehicle with possible immunomodulatory effects, and c-CPE, as a targeting tag, synergistically assist to stimulate systemic and local immunity. This proposed recombinant
system might be useful in the expression of other antigenic peptides, making it as a promising tool for oral delivery of vaccines or therapeutic proteins.