Chimeric Antibody 14D5 Protects Mice against the Far-Eastern, Siberian, and European Tick-borne Encephalitis Virus

Tick-borne encephalitis virus (TBEV), belonging to the Flaviviridae family, is the most significant pathogen transmitted by Ixodes ticks and causing one of the most severe human neuroinfections. In Russia, serum immunoglobulin produced from the donor blood is currently used for post-exposure prophylactic and therapy of tick-borne encephalitis virus. However, it is known that preparations obtained from donated blood have certain disadvantages, and therefore development of novel preparations for post exposure prophylaxis and therapy of tick-borne encephalitis is required. To develop an alternative preparation, which does not include donor blood, a chimeric antibody ch14D5 against glycoprotein E of TBEV was constructed.This study was aimed to investigate protective efficacy of the chimeric antibody ch14D5 against the Far-Eastern, Siberian, and European subtypes of TBEV in in vivo experiments.A peripheral mouse model of tick-borne encephalitis was used in this study: the chimeric antibody ch14D5 was administrated intravenously in mice one day after their intraperitoneal infection with TBEV strains Sofjin, Vasilchenko, and Absettarov. Anti-TBEV serum immunoglobulin was used as a control preparation, which was administered in the same way. Protective efficacy of the chimeric antibodies 14D5 was assessed using the log-rank test. In the study, the presence or absence of antibody-dependent enhancement of infection (ADE) was examined when mice, infected with different subtypes of the TBEV, got the antibody ch14d5.Obtained results demonstrated high efficacy of the ch14D5 antibody in post-exposure prophylaxis of the disease in mice infected with any of the used TBEV strains, as well as the absence of ADE.It was shown that protective efficacy of antibody ch14D5 is higher than that of the anti-TBEV serum immunoglobulin, and antibody ch14D5 could be used for development of a therapeutic preparation for post-exposure prophylaxis

Special Issue “Bacteriophage Genomics”: Editorial

Virus genomics as a separate branch of biology has emerged relatively recently [...

Applications of Bacteriophages in the Treatment of Localized Infections in Humans

In the recent years, multidrug-resistant bacteria have become a global threat, and phage therapy may to be used as an alternative to antibiotics or, at least, as a supplementary approach to treatment of some bacterial infections. Here, we describe the results of bacteriophage application in clinical practice for the treatment of localized infections in wounds, burns, and trophic ulcers, including diabetic foot ulcers. This mini-review includes data from various studies available in English, as well as serial case reports published in Russian scientific literature (with, at least, abstracts accessible in English). Since, it would be impossible to describe all historical Russian publications; we focused on publications included clear data on dosage and rout of phage administration

An Update of Orthopoxvirus Molecular Evolution

Although variola virus (VARV) has been eradicated through widespread vaccination, other orthopoxviruses pathogenic for humans circulate in nature. Recently, new orthopoxviruses, including some able to infect humans, have been found and their complete genomes have been sequenced. Questions about the orthopoxvirus mutation rate and the emergence of new threats to humankind as a result of the evolution of circulating orthopoxviruses remain open. Based on contemporary data on ancient VARV DNA and DNA of new orthopoxvirus species, an analysis of the molecular evolution of orthopoxviruses was carried out and the timescale of their emergence was estimated. It was calculated that the orthopoxviruses of the Old and New Worlds separated approximately 40,000 years ago; the recently discovered Akhmeta virus and Alaskapox virus separated from other orthopoxviruses approximately 10,000–20,000 years ago; the rest of modern orthopoxvirus species originated from 1700 to 6000 years ago, with the exception of VARV, which emerged in approximately 300 AD. Later, there was a separation of genetic variants of some orthopoxvirus species, so the monkeypox virus West African subtype originated approximately 600 years ago, and the VARV minor alastrim subtype emerged approximately 300 years ago

The smallest isoform of Metridia longa luciferase as a fusion partner for hybrid proteins

Bioluminescent proteins are widely used as reporter molecules in various in vitro and in vivo assays. The smallest isoform of Metridia luciferase (MLuc7) is a highly active, naturally secreted enzyme which, along with other luciferase isoforms, is responsible for the bright bioluminescence of marine copepod Metridia longa. In this study, we report the construction of two variants of a hybrid protein consisting of MLuc7 and 14D5a single-chain antibody to the surface glycoprotein E of tick-borne encephalitis virus as a model fusion partner. We demonstrate that, whereas fusion of a single-chain antibody to either N- or C-terminus of MLuc7 does not affect its bioluminescence properties, the binding site on the single-chain antibody influences its binding capacity. The affinity of 14D5a-MLuc7 hybrid protein (KD = 36.2 nM) where the C-terminus of the single-chain antibody was fused to the N-terminus of MLuc7, appeared to be 2.5-fold higher than that of the reverse, MLuc7-14D5a (KD = 87.6 nM). The detection limit of 14D5a-MLuc7 hybrid protein was estimated to be 45 pg of the recombinant glycoprotein E. Although the smallest isoform of M. longa luciferase was tested as a fusion partner only with a single-chain antibody, it is reasonable to suppose that MLuc7 can also be successfully used as a partner for genetic fusion with other proteins

First crAss-Like Phage Genome Encoding the Diversity-Generating Retroelement (DGR)

A new crAss-like genome encoding diversity-generating retroelement (DGR) was found in the fecal virome of a healthy volunteer. The genome of the phage referred to as the crAssphage LMMB, belonged to the candidate genus I of the AlphacrAssvirinae subfamily. The DGR-cassette of the crAssphage LMMB contained all the essential elements: the gene encoding reverse transcriptase (RT), the target gene (TG) encoding the tail-collar fiber protein, and variable and template repeats (VR and TR) with IMH (initiation of mutagenic homing) and IMH* sequences at the 3′-end of the VR and TR, respectively. Architecture of the DGR-cassette was TG-VR(IMH)-TR(IMH*)-RT and an accessory variable determinant (avd) was absent from the cassette. Analysis of 91 genomes and genome fragments from genus I of the AlphacrAssvirinae showed that 15 (16%) of the genomes had DGRs with the same architecture as the crAssphage LMMB, while 66 of the genomes contained incomplete DGR-cassettes or some elements of the DGR

Computational and Rational Design of Single-Chain Antibody against Tick-Borne Encephalitis Virus for Modifying Its Specificity

Tick-borne encephalitis virus (TBEV) causes 5−7 thousand cases of human meningitis and encephalitis annually. The neutralizing and protective antibody ch14D5 is a potential therapeutic agent. This antibody exhibits a high affinity for binding with the D3 domain of the glycoprotein E of the Far Eastern subtype of the virus, but a lower affinity for the D3 domains of the Siberian and European subtypes. In this study, a 2.2-fold increase in the affinity of single-chain antibody sc14D5 to D3 proteins of the Siberian and European subtypes of the virus was achieved using rational design and computational modeling. This improvement can be further enhanced in the case of the bivalent binding of the full-length chimeric antibody containing the identified mutation

New human single chain anti-idiotypic antibody against benzo[a]pyrene

The naïve library from the lymphocytes of healthy humans was screened by murine single-stranded idiotypic antibodies against benzo[a]pyrene (pSh). The phage clone which contained of anti-idiotypic antibody against benzo[a]pyrene, designated as A4, was chosen for further work because of highly specific to pSh. The available protein databases were searched. The A4 amino acid sequence was unique and 76% identical to a sequence in antibody against interferon g. The A4 protein was expressed in bacteria and purified by two different methods: His-tagged A4 and CBD-fusion A4. Both the A4 bound to pSh and also to the human single chain idiotypic antibody against the benzo[a]pyrene (T72) by ELISA. The Kd values of A4 for pSh and T72 were very close: 4.44 × 10-7 M and 5.71 × 10-7M, respectively. A4 was a competitor with benzo[a]pyrene for binding sites of both idiotypic pSh and T72 in competitive ELISA. Thus, A4 was a high affinity anti-idiotypic against benzo[a]pyrene which recognised pSh and T72 active sites

Dog survey in Russian veterinary hospitals: tick identification and molecular detection of tick-borne pathogens

Abstract Background Species of Canidae in Russia can be infested with up to 24 different tick species; however, the frequency of different tick species infesting domestic dogs across Russia is not known. In addition, tick-borne disease risks for domestic dogs in Russia are not well quantified. The goal of this study was to conduct a nationwide survey of ticks collected from infested dogs admitted to veterinary clinics in Russian cities and to identify pathogens found in these ticks. Methods Ticks feeding on dogs admitted to 32 veterinary clinics in 27 major cities across Russia were preserved in ethanol and submitted to a central facility for examination. After identification, each tick was evaluated for infection with known tick-borne pathogens using PCR. Results There were 990 individual ticks collected from 636 dogs. All collected ticks belonged to the Ixodidae (hard ticks) and represented 11 species of four genera, Dermacentor, Ixodes, Rhipicephalus and Haemaphysalis. Four most common tick species were D. reticulatus, followed by I. persulcatus, I. ricinus and R. sanguineus. Ixodes persulcatus ticks were found to be infected with 10 different pathogens, and ticks of this species were more frequently infected than either D. reticulatus or I. ricinus. Ixodes persulcatus females were also more frequently co-infected with two or more pathogens than any other tick. Pathogenic species of five genera were detected in ticks: Anaplasma centrale, A. phagocytophilum and A. marginale; Babesia canis, B. microti, B. venatorum, B. divergens, B. crassa and B. vogeli; Borrelia miyamotoi, B. afzelii and B. garinii; Ehrlichia muris, E. canis and E. ruminantum; and Theileria cervi. Anaplasma marginale, E. canis, B. crassa, B. vogeli and T. cervi were detected in I. persulcatus, and Babesia canis in D. marginatum, for the first time in Russia. Conclusions Multiple ticks from four genera and 11 species of the family Ixodidae were collected from domestic dogs across Russia. These ticks commonly carry pathogens and act as disease vectors. Ixodes persulcatus ticks present the greatest risk for transmission of multiple arthropod-borne pathogens