Bifidobacteria from human origin: interaction with phagocytic cells.

Area of Science:

• Immunology
• Microbiology
• Probiotics

Background:

• Phagocytic cells are crucial for host immune response.
• Bifidobacteria are known probiotics with immune-modulating potential.
• Understanding host-microbe interactions is vital for probiotic efficacy.

Purpose of the Study:

• To investigate the interaction patterns of human-origin bifidobacteria with monocytic THP-1 cells.
• To evaluate the impact of these interactions on immune cell responses.
• To elucidate mechanisms behind probiotic biological effects.

Main Methods:

• Studied interaction of eight Bifidobacterium strains with THP-1 cells under nonopsonic conditions.
• Assessed parameters including cell association/internalization, HLA-DR and TLR2 expression, and M1/M2 macrophage polarization.
• Utilized Lysotracker and transferrin for colocalization studies.

Main Results:

• Identified distinct high and low interaction patterns among Bifidobacterium strains.
• Both B. bifidum CIDCA 5310 and B. adolescentis CIDCA 5317 stimulated TLR2 expression.
• Strain CIDCA 5310 showed enhanced lysosomal colocalization and upregulated both M1 and M2 macrophage markers, while CIDCA 5317 increased HLA-DR expression.

Conclusions:

• Human-origin bifidobacteria exhibit diverse interaction profiles with phagocytic cells.
• These varied interactions lead to distinct cellular responses, including differential macrophage polarization.
• Findings enhance understanding of probiotic mechanisms and their impact on host immunity.