Prebiotic effect of sialylated immunoglobulin G on gut microbiota of patients with inflammatory bowel disease by in vitro fermentation

Abstract

Sialylated immunoglobulin G (IgG) is a kind of glycoproteins in breast milk with the property of anti-inflammation. Our previous work showed that sialylated IgG could significantly promote the growth of Bifidobacterium in the gut microbiota of healthy volunteers. Nevertheless, whether sialylated IgG can benefit patients with inflammatory bowel disease (IBD) as prebiotics remains unclear. Therefore, its prebiotic effect on the gut microbiota of IBD patients was investigated by in vitro fermentation in this study. The results showed that sialylated IgG could significantly enhance the diversity, richness and composition of gut microbiota in IBD samples compared with non-sialylated IgG. In detail, sialylated IgG not only improved the growth of three common genera (Romboutsia, Prevotella and Akkermansia) with low relative abundance in IBD samples but also increased the genera (Bifidobacterium, Actinomyces, Atopobium and Citrobacter) with low relative abundance both in healthy and IBD fecal samples. Correspondingly, the contents of short-chain fatty acids for fermentation group of fecal sample from IBD patients with sialylated IgG as the carbon source were higher than those for fermentation group of fecal sample from IBD patients with non-sialylated IgG as the carbon source. In addition, the metabolic pathway results confirmed that sialylated IgG upregulated the functional genes related to hydrolysis, absorption and utilization of carbohydrates. The transcriptome sequencing results further showed that sialylated IgG could induce particular gene expression of Bifidobacterium bifidum to modulate the gut microbiota of IBD patients. Thus, as a kind of natural dietary component, sialylated IgG has potential applications in treating IBD.