Gut Microbiota in Children with Hand Foot and Mouth Disease on 16S rRNA Gene Sequencing.

Hand foot and mouth disease (HFMD) is a contagious and seasonal viral disease in children. The gut microbiota of HFMD children is not clear now. The study aimed to explore the gut microbiota of HFMD children. The 16S rRNA gene of the gut microbiota of ten HFMD patients and ten healthy children were sequenced on the NovaSeq and PacBio platforms respectively. There were significant differences in gut microbiota between the patients and healthy children. The diversity and abundance of gut microbiota in HFMD patients were lower than that in healthy children. The species Roseburia inulinivorans and Romboutsia timonensis were more abundant in healthy children than those in HFMD patients, which suggests that the two species may be used as probiotics for adjusting the gut microbiota of HFMD patients. Meanwhile, the results of 16S rRNA gene sequences from the two platforms were different. The NovaSeq platform identified more microbiota and has the characteristics of high throughput, short time and low price. However, the NovaSeq platform has low resolution at the species level. The PacBio platform has high resolution based on its long reads length, which is more suitable for species-level analysis. But, the shortcomings of the high price and low throughput of PacBio still need to be overcome. With the development of sequencing technology, the reduction in sequencing price and the increase in throughput will promote the third-generation sequencing technology used in the study of gut microbes.

A new EV71 VP3 epitope in norovirus P particle vector displays neutralizing activity and protection in vivo in mice.

Enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16), as the main agents causing hand, foot and mouth disease (HFMD), have become a serious public health concern in the Asia-Pacific region. Recently, various neutralizing B cell epitopes of EV71 were identified as targets for promising vaccine candidates. Structural studies of Picornaviridae indicated that potent immunodominant epitopes typically lie in the hypervariable loop of capsid surfaces. However, cross-neutralizing antibodies and cross-protection between EV71 and CVA16 have not been observed. Therefore, we speculated that divergent sequences of the two viruses are key epitopes for inducing protective neutralizing responses. In this study, we selected 10 divergent epitope candidates based on alignment of the EV71 and CVA16 P1 amino acid sequences using the Multalin interface page, and these epitopes are conserved among all subgenotypes of EV71. Simultaneously, by utilizing the norovirus P particle as a novel vaccine delivery carrier, we identified the 71-6 epitope (amino acid 176-190 of VP3) as a conformational neutralizing epitope against EV71 in an in vitro micro-neutralization assay as well as an in vivo protection assay in mice. Altogether, these results indicated that the incorporation of the 71-6 epitope into the norovirus P domain can provide a promising candidate for an effective synthetic peptide-based vaccine against EV71.