Intestinal mucin-type O-glycans: the major players in the host-bacteria-rotavirus interactions.

Rotavirus (RV) causes severe diarrhea in young children and animals worldwide. Several glycans terminating in sialic acids (SAs) and histo-blood group antigens (HBGAs) on intestinal epithelial cell (IEC) surface have been recognized to act as attachment sites for RV. IECs are protected by the double layer of mucus of which O-glycans (including HBGAs and SAs) are a major organic component. Luminal mucins, as well as bacterial glycans, can act as decoy molecules removing RV particles from the gut. The composition of the intestinal mucus is regulated by complex O-glycan-specific interactions among the gut microbiota, RV and the host. In this review, we highlight O-glycan-mediated interactions within the intestinal lumen prior to RV attachment to IECs. A better understanding of the role of mucus is essential for the development of alternative therapeutic tools including the use of pre- and probiotics to control RV infection.

Glycan-mediated interactions between bacteria, rotavirus and the host cells provide an additional mechanism of antiviral defence.

Limited efficacy of rotavirus (RV) vaccines in children in developing countries and in animals remains a significant problem necessitating further search for additional approaches to control RV-associated gastroenteritis. During cell attachment and entry events, RV interacts with cell surface O-glycans including histo-blood group antigens (HBGAs). Besides modulation of the protective immunity against RV, several commensal and probiotic bacteria were shown to express HBGA-like substances suggesting that they may affect RV attachment and entry into the host cells. Moreover, some beneficial bacteria have been shown to possess the ability to bind host HBGAs via sugar specific proteins called lectins. However, limited research has been done to evaluate the effects of HBGA-expressing and/or HBGA-binding bacteria on RV infection. The aim of this study was to investigate the ability of selected commensal and probiotic bacteria to bind different RV strains via HBGAs and to block RV infection of IPEC-J2 cells. Our data indicated that Gram-negative probiotic Escherichia coli Nissle 1917 (E. coli Nissle 1917) and commensal Gram-positive (Streptococcus bovis and Bifidobacterium adolescentis) and Gram-negative (Bacteroides thetaiotaomicron, Clostridium clostridioforme and Escherichia coli G58 (E. coli G58) bacteria of swine origin expressed HBGAs which correlated with their ability to bind group A and C RVs. Additionally, Gram-positive E. coli 1917 and E. coli G58 demonstrated the ability to block RV attachment onto IPEC-J2 cells. Taken together, our results support the hypothesis that physical interactions between RVs and HBGA-expressing beneficial bacteria may limit RV replication.

[Evaluation of the molecularbiological properties of human rotavirus A strain WA.]

BACKGROUND: Rоtaviruses are amоng the leading causes of severe diarrhea in children all over the Wоrld. Vaccination is considered to be the mоst effective way to cоntrоl the disease. Currently available vaccines for prevention of rоtavirus infection are based on live attenuated rotavirus strains human оr animal origin. OBJECTIVES: The aim of this investigation was to study the biological and genetic properties of an actual epidemic human rotavirus A (RVA) strain Wa G1P[8] genotype. METHODS: RVA Wa reproduction in a monolayer continuous cell lines, purification and concentration of RVA antigen, PAAG electrophoresis and Western-Blot, electrophoresis of viral genomic RNA segments, sequencing. RESULTS: Human RVA G1P[8] Wa strain biological and molecular genetic properties were assessed in the process of the adaptation to MARC145 continuous cell line. Cell cultured RVA antigen was purified, concentrated and then characterized by the method of PAAG electrophoresis and immunoblot. To verify RVA Wa genome identity, electrophoresis of viral genomic RNA segments was performed. The lack of accumulation of changes in the RVA Wa genome during adaptation to various cell cultures and during serial passages was demonstrated by sequencing fragments of the viral genome. CONCLUSIONS: RVA Wa strain is stable, it possesses high biological activity: it has been successfully adapted to the MARC145 cell line and RVA Wa virus titer after the adaptation reached 7,5-7,7 lg TCID50/ml. The identity of the cultivated RVA to the original strain Wa G1P[8] was confirmed.

[Molecular genetic characteristics of the virus isolated from patients with human acute encephalomyelitis and multiple sclerosis].

The study of the antigenic and molecular genetic structure of human acute encephalomyelitis virus (HAEV) showed a high similarity of the HAEV N gene with the homologous gene of the fixed rabies virus strain. The results of the nucleotide sequence analysis indicate that HAEV belongs to the lyssavirus genotype 1. The N gene sequence is the closest to those of the ERA-CB20-M and RV-97 strains of the rabies virus. The need for further research into the role of the human acute encephalomyelitis virus in human pathology stems from past surveys that revealed the presence of the VNAs against this virus in 6 per cent of the blood received from donors in the USA and in each third among the patients with multiple sclerosis in the former USSR.