Modulation of T Regulatory and Dendritic Cell Phenotypes Following Ingestion of Bifidobacterium longum, AHCC® and Azithromycin in Healthy Individuals

Authors: Abeed H. Chowdhury, Miguel Cámara, Chandan Verma, Oleg Eremin, Anil D. Kulkarni, and Dileep N. Lobo

Journal: Nutrients

Study Design: The study was a double-blind, randomized controlled trial that investigated the effects of oral administration of probiotics (Bifidobacterium longum BB536), prebiotics (AHCC®), or a combination (synbiotic) on T cell and dendritic cell (DC) phenotypes and function in healthy volunteers. The study also included an antibiotic treatment phase to assess the persistence of immunomodulatory effects after antibiotic use.

Participants: 40 healthy male volunteers

Intervention: The volunteers were divided into four groups:

• Placebo group
• Probiotic group (BB536)
• Prebiotic group (AHCC®)
• Synbiotic group (BB536 + AHCC®)

The interventions were administered for 12 days, with all groups receiving azithromycin (250 mg once daily) for the last 5 days.

Outcome Measures:

• Cytokine profiles from purified CD3+ T cells stimulated with PDB-ionomycin
• CD4+ CD25+ Foxp3 expression (a marker of T regulatory cell activity)
• Peripheral blood DC subsets (plasmacytoid dendritic cells [pDCs] and myeloid dendritic cells [mDCs])

Summary: The study found that the oral intake of AHCC® and BB536 may modulate T regulatory and DC phenotypes to favor anti-inflammatory responses following antibiotic usage. The combination of BB536 and AHCC® led to an increase in the percentage of mDCs and a shift towards the mDC2 subset, which is associated with anti-inflammatory responses. The study also observed an increase in Foxp3 expression in volunteers receiving BB536, suggesting an increase in T regulatory cell activity. However, there were no significant differences in cytokine secretion from stimulated CD3+ T cells between the treatment groups. The study concluded that the oral intake of AHCC® and BB536 may have immunomodulatory effects, but further research is needed to elucidate the precise mechanisms and clinical implications of these findings.