Designing a multi-epitope vaccine against Peptostreptococcus anaerobius based on an immunoinformatics approach

Peptostreptococcus anaerobius is an anaerobic bacterium,which has been found selectively en-riched in the fecal and mucosal microbiota of colorectal cancer(CRC)patients.Emerging evidence suggest P.anaerobius may contribute to the development of CRC in human.In this study,we designed a multi-epitope chimeric vaccine against P.anaerobius PCWBR2,a recently identified adhesin that interacts directly with colon cell lines by bindingα2/β1 integrin frequently overexpressed in human CRC tumors and cell lines.Immunoinformatics tools predicted six cytotoxic T lymphocyte epitopes,five helper T lymphocyte epitopes,and six linear B lymphocyte epitopes.The predicted epitopes were joined with AAY or GPGPG linkers and a previously reported TLR4 agonist was added to the vaccine construct’s N terminal as an adjuvant using EAAAK linkers and the order of epitopes was optimized.Further in silico analysis revealed that the vaccine construct possesses satisfactory antigenicity,allergenicity,solubility,physicochemical properties,adjuvant-TLR4 molecular docking,and immune profile characteristics.Our study provided a promising design for vaccines against P.anaerobius.

The microbiome in inflammatory bowel diseases:from pathogenesis to therapy

Inflammatory bowel disease(IBD)has become a global disease with accelerating incidence worldwide in the 21st century while its accurate etiology remains unclear.In the past decade,gut microbiota dysbiosis has consistently been associated with IBD.Although many IBDassociated dysbiosis have not been proven to be a cause or an effect of IBD,it is often hypothesized that at least some of alteration in microbiome is protective or causative.In this article,we selectively reviewed the hypothesis supported by both association studies in human and pathogenesis studies in biological models.Specifically,we reviewed the potential protective bacterial pathways and species against IBD,as well as the potential causative bacterial pathways and species of IBD.We also reviewed the potential roles of some members of mycobiome and virome in IBD.Lastly,we covered the current status of therapeutic approaches targeting microbiome,which is a promising strategy to alleviate and cure this inflammatory disease.

Association between the nasopharyngeal microbiome and metabolome in patients with COVID-19

SARS-CoV-2,the causative agent for COVID-19,infect human mainly via respiratory tract,which is heavily inhabited by local microbiota.However,the interaction between SARS-CoV-2 and nasopharyngeal microbiota,and the association with metabolome has not been well characterized.Here,metabolomic analysis of blood,urine,and nasopharyngeal swabs from a group of COVID-19 and non-COVID-19 patients,and metagenomic analysis of pharyngeal samples were used to identify the key features of COVID-19.Results showed lactic acid,L-proline,and chlorogenic acid methyl ester(CME)were significantly reduced in the sera of COVID-19 patients compared with non-COVID-19 ones.Nasopharyngeal commensal bacteria including Gemella morbillorum,Gemella haemolysans and Leptotrichia hofstadii were notably depleted in the pharynges of COVID-19 patients,while Prevotella histicola,Streptococcus sanguinis,and Veillonella dispar were relatively increased.The abundance of G.haemolysans and L.hofstadii were significantly positively associated with serum CME,which might be an anti-SARS-CoV-2 bacterial metabolite.This study provides important information to explore the linkage between nasopharyngeal microbiota and disease susceptibility.The findings were based on a very limited number of patients enrolled in this study;a larger size of cohort will be appreciated for further investigation.