Sublingual immunization with the phosphate-binding-protein (PstS) reduces oral colonization by Streptococcus mutans

Area of Science:

• Microbiology
• Immunology
• Vaccine Development

Background:

• Bacterial ATP-binding cassette (ABC) transporters are vital for bacterial physiology and pathogenicity.
• Streptococcus mutans, a key cause of dental caries, possesses ABC transporters like the phosphate uptake system (Pst).
• The PstS component of S. mutans Pst has been implicated in bacterial adherence.

Purpose of the Study:

• To generate a recombinant PstS protein (rPstS) from S. mutans.
• To evaluate the immunogenicity and protective potential of rPstS after sublingual mucosal immunization.
• To assess the ability of induced antibodies to inhibit bacterial adhesion and colonization.

Main Methods:

• Generation of a structurally preserved recombinant S. mutans PstS protein.
• Sublingual immunization of mice with rPstS and an adjuvant.
• Measurement of systemic and secreted antibody responses (IgA-secreting cells).
• Assessment of serum antibody-mediated inhibition of bacterial adhesion in naive mice.
• Evaluation of protection against oral colonization in actively immunized mice.

Main Results:

• Sublingual immunization with rPstS successfully induced systemic and secreted antibody responses in mice.
• Serum antibodies from immunized mice inhibited S. mutans adhesion to oral surfaces.
• Mice immunized with rPstS showed partial protection against oral colonization by S. mutans.

Conclusions:

• S. mutans PstS is a viable target antigen for vaccine development against dental caries.
• Sublingual administration of rPstS elicits specific and protective antibody responses.
• These findings offer a promising strategy for developing novel vaccines to prevent dental caries.