Reviewed Marked as Reviewed by ChiomaBlessing on 2024-2-14
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Authors
Harry Cheuk Hay Lau, Joseph Jao-Yiu Sung
Keywords:
CpG- oligodeoxynucleotide therapy, Gut microbiota, adoptive cell transfer, blockade-induced adverse events, gastrointestinal cancer, immune checkpoint blockade, probiotics
The human gastrointestinal tract harbor thousands of microbial species. For example, intestines consist of a dense community with around 1013 microbes mainly from phyla Bacteroidetes and Firmicutes;1 while microbial abundance in the stomach is the least along the tract due to its extreme acidity with predominant expression of Firmicutes and Proteobacteria.2 These microorganisms form a microbiota (referring to an ecological community of microbes that is found within a specific environment), which interacts with a variety of host cells to contribute physiological functions including nutrient metabolism and gut barrier regulation.3,4 In particular, the gut microbiota substantially contributes to immune homeostasis as exemplified by using germ-free animals (referring to animals raised in the strict sterile conditions that have no microbes living in/on them), which displayed impaired development of regulatory T cells (TReg) and poor growth of gut-associated lymphoid tissues.3–5 Whereas the host immunity can, in turn, manipulate the microbial profile: secretary immunoglobulin-A (IgA) from gut plasma cells has reactivity to a broad spectrum of microbes, and these IgA could enhance translocation of selected commensals into lymphoid tissues to facilitate antigen presentation and regulate microbial diversity.
