Novel LysM motifs for antigen display on lactobacilli for mucosal immunization

RAYA-TONETTI, FERNANDA; MÜLLER, MELISA; SACUR, JACINTO; KITAZAWA, HARUKI; VILLENA, JULIO; VIZOSO-PINTO, MARIA GUADALUPE

Scientific Reports

Nature

Año: 2021 vol. 11

We characterized two LysM domains of Limosilactobacillus fermentum, belonging to proteins Acglu(GenBank: KPH22907.1) and Pgb (GenBank: KPH22047.1) and bacterium like particles (BLP) derivedfrom the immunomodulatory strain Lacticaseibacillus rhamnosus IBL027 (BLPs027) as an antigendisplay platform. The fluorescence protein Venus fused to the novel LysM domains could bind tothe peptidoglycan shell of lactobacilli and resisted harsh conditions such as high NaCl and ureaconcentrations. Acglu with five LysM domains was a better anchor than Pgb baring only one domain.Six-week-old BALB/c mice were nasally immunized with the complex Venus-Acglu-BLPs027 at days0, 14 and 28. The levels of specific serum IgG, IgG1 and IgG2a and the levels of total immunoglobulins(IgT) and IgA in broncho-alveolar lavage (BAL) were evaluated ten days after the last boosting. Venus-Acglu-BLPs027, nasally administered, significantly increased specific BAL IgT and IgA, and serum IgGlevels. In addition, spleen cells of mice immunized with Venus-Acglu-BLPs027 secreted TNF-α, IFN-γand IL-4 when stimulated ex vivo in a dose-dependent manner. We constructed a Gateway compatibledestination vector to easily fuse the selected LysM domain to proteins of interest for antigen displayto develop mucosal subunit vaccines.