Streptococcus salivarius CCFM1416 Modulates Oral Immunity via IL-17/IKBζ and Combats Candida albicans Infection

Area of Science:

• Oral microbiology
• Immunology
• Probiotic research

Background:

• Oropharyngeal candidiasis (OPC) is common in immunocompromised individuals.
• Probiotics can enhance antimicrobial defenses against oral infections.
• Human beta-defensin-2 (HBD-2) plays a key role in combating Candida albicans.

Purpose of the Study:

• Identify oral commensal bacteria that promote HBD-2 production.
• Evaluate the efficacy of identified bacteria in preventing OPC.
• Assess the safety of the probiotic candidate.

Main Methods:

• Screened 35 Streptococcus salivarius strains for HBD-2 promotion using HOK-16B cells.
• Validated promising strains in a murine OPC model.
• Conducted a 14-day oral toxicity study in vivo.

Main Results:

• Two S. salivarius strains significantly promoted HBD-2 secretion.
• S. salivarius CCFM1416 activated the IL-17/IKBζ pathway, upregulating HBD-2 expression.
• Oral intervention with S. salivarius CCFM1416 reduced C. albicans colonization and adhesion.
• S. salivarius CCFM1416 demonstrated safety in vivo.

Conclusions:

• S. salivarius CCFM1416 effectively prevents OPC by enhancing host HBD-2 production.
• This strain is a promising probiotic candidate for preventing oral mucosal infections.
• The study highlights the potential of targeted probiotics in managing opportunistic fungal infections.