Influence of changes in the intestinal microflora on the immune function in mice

Area of Science:

• Microbiology
• Immunology
• Gastroenterology

Background:

• Intestinal microbiota composition influences host health and immune function.
• Antibiotic administration significantly alters gut microbiota.
• The impact of immune function on gut microbiota remains largely unclear.

Purpose of the Study:

• To investigate the relationship between lymphocyte composition, function, and the intestinal microbiota after antibiotic treatment in mice.
• To elucidate how antibiotic-induced changes in gut microbiota affect immune cell populations and cytokine production.

Main Methods:

• Mice were treated with or without antibiotics to modify gut microbiota.
• Metagenomic analysis targeting 16S rRNA was used for microbiota profiling.
• Flow cytometry assessed lymphocyte subsets (CD3+, CD19+) in splenocytes.
• Concanavalin A stimulation and real-time PCR measured cytokine gene expression (interferon-γ, IL-6, IL-13).

Main Results:

• Antibiotic treatment shifted microbiota from Firmicutes predominance to Bacteroidetes predominance, reducing overall diversity.
• Lymphocyte analysis revealed decreased CD3+ cells and increased CD19+ cells in antibiotic-treated mice.
• Splenocyte cytokine gene expression, including interferon-γ, IL-6, and IL-13, was significantly downregulated following antibiotic treatment.

Conclusions:

• Antibiotic-induced alterations in intestinal microbiota composition significantly impact lymphocyte populations in splenocytes.
• Changes in gut microbiota composition affect the host's immune response, particularly T cell-mediated cytokine production.
• This study highlights the intricate connection between the gut microbiome and the host immune system, emphasizing the effects of antibiotic intervention.