The Mouse Gut Microbiome Is Required For Response To Hepatitis B Vaccine

Objective:Chronic hepatitis B infection,caused by the hepatitis B virus(HBV),remains a serious public health problem in the world.Vaccination against HBV at birth is the main strategy to eliminate infection of hepatitis B and reduce the incidence of liver cancer.Individuals who do not respond adequately to the HBV vaccine remain at risk for hepatitis B infection.The mechanism of no or low response to the hepatitis B vaccine remains unclear.The previous study showed microbiome development is directly linked to the innate and adaptive immune system to develop and function.Transplantation of the fecal sample from a healthy donor to the gastrointestinal tract of a diseased individual can modulate the gut microbiota.The main purpose of this study is to investigate the role of gut microbiota on HBs Ag-mediated humoral immune response and explore whether partially reconstitute the gut microbiota after the cessation of antibiotics exposure would rescue the impaired responses to the Hepatitis B vaccine-induced by antibiotic-driven dysbiosis in early life.Methods:The experimental methods used in this study include 1.Mice treated with antibiotics or no treatment control mice were immunized with the Hepatitis B vaccine.Hepatitis B surface antibody(HBs Ab)Ig G level in plasma was detected by ELISA.2.16 S r DNA gene sequencing was used to profile the composition of the gut microbiota.3.Liquid chromatography-mass spectrometry(LC-MS)based metabolomics was performed to examine the metabolites of the gut microbiota.4.Mice exposed to antibiotics after weaning were gavaged with the fecal contents of age-matched,untreated mice,or antibiotic-treated mice.After immunization with the Hepatitis B vaccine,the level of HBs Ab Ig G、Ig G1、Ig G2 a was detected by ELISA.5.The B cell response by analyzing B cell subsets in the spleen and blood using flow cytometry.The plasmablasts,plasma cells,and GC B cells were analyzed.Results:1.Early-life antibiotic treatment induced an impaired response to the Hepatitis B vaccine,as adult mice exposed to the same dose antibiotics did not have impaired vaccine antibody response.2.A different profile of gut microbiota was observed in mice treated with antibiotics compared to controls.At the phylum level,the relative abundance of Firmicutes,Proteobacteria,and Actinobacteria decreased.At the genus level,a decreased level of Lactobacillus was observed.3.Meanwhile,there were significantly decreased fecal metabolites with the perturbed gut microbiota,especially compounds vitamins,amino acids,and fatty acids.According to the KEGG functional annotation,the metabolic pathways involved in differential metabolites include metabolism of cofactors and vitamins,amino acid metabolism,and energy metabolism.4.Antibiotic-treated mice received a fecal microbiota transfer(FMT)from untreated mice showed an increased HBs Ab Ig G,Ig G1,and Ig G2 a responses to antibiotic-treated mice that received fecal contents collected from antibiotic exposed mice.5.We found that plasmablasts and plasma cells in the spleen and blood were present at lower frequencies in antibiotic-treated mice when compared to untreated mice.Intriguingly,these cells significantly increased after receiving fecal contents from age-matched,untreated mice.6.Furthermore,GC B cells were at lower levels after antibiotic treatment and significantly increased after reconstitute the gut microbiota.Conclusion:1.These findings suggested that perturbation of the gut microbiota induced an impaired humoral immunity to HBs Ag for mice in their early-life.2.The decreased levels of Firmicutes,Proteobacteria,Actinobacteria,and decreased Lactobacillus and the related pathways such as metabolism of cofactors and vitamins,amino acid metabolism,and energy metabolism may be a contributing factor to the lower or no response to the Hepatitis B vaccine.3.The impaired antibody response to the Hepatitis B vaccine could be rescued by the reconstitution of the gut microbiota following antibiotic exposure.Antibiotic treatment and FMT could impact the levels of plasma cells and plasmablasts in spleen and blood.The levels of GC B cell changes induced by gut microbiota could be one of the mechanisms of how gut microbiota impacts humoral immunity.