Vol 63, No 2 (2018)

The data on a recently revealed novel filovirus (Lloviu virus, family Filoviridae, genera Cuevavirus) in Europe are viewed in this issue. The molecular-biological properties of genome fragments of Lloviu virus were isolated from perished bats (Miniopterus sсhreibersii). Because infectious Lloviu virus has not been isolated yet, the capacity of virus to infect cells of different species and its potential to cause disease in humans is unclear. The recombinant vectors (vesicular stomatitis virus and plasmids) expressing structural proteins of Lloviu virus were used to study different elements of the virus. The question of interaction of structural proteins of Lloviu virus expressed by recombinant vectors with receptors of bat and human cells is considered. The possibility of pathogenicity of the novel agent for humans is considered. The conclusion is made about the necessity of continuous epidemical and epizootical monitoring of the new filovirus infection.

One of the main problems in the area of influenza prophylaxis and pandemic prevention is the development of cross-reactive vaccines, i.e. vaccines directed against all subtypes of human influenza viruses. Such vaccines are being developed in many countries for more than 10 years. A number of vaccines are presently undergoing clinical trials. We created Uniflu candidate vaccine based on recombinant HBc4M2e protein consisting of 4 tandem-connected copies of the highly conserved ectodomain of M2 protein of the influenza A virus. These 4 copies were genetically fused to the carrier protein, namely hepatitis B core antigen. Commercially available Derinat was used as adjuvant in the candidate vaccine. Preclinical studies on laboratory animals (mice, ferrets) demonstrated that immunization with Uniflu leads to significantly higher level of specific immunoglobulins in the blood and bronchoalveolar lavages. Moreover, it produces immunoglobulins belonging to subtype IgG2a that is the most important mediator of antibody-dependent cytotoxicity. The vaccine under review stimulates the proliferation of T-lymphocytes, as well as the formation of CD4+ and CD8+ T-cells synthesizing ɣ-IFN. When infected with the lethal doses (5 LD50) of influenza A viruses of the subtypes H1N1, H2N2, H3N2, and H1N1pdm09, immunized animals typically developed mild form of illness. This kept them alive in 90-100% of cases, which demonstrated almost complete protection from death. Replication of the virus in the lungs of immunized mice was reduced by 1.8-4.8 log10. High immunogenicity of the vaccine, and reduced clinical symptoms following experimental infection, were demonstrated in ferrets as well. The developed recombinant vaccine Uniflu has high specific activity and cross-protection. Uniflu can be proposed as pre-pandemic vaccine, provided that it passes clinical trials.

Introduction. Human herpes virus type 6 (HHV 6) can cause serious infectious complications in immunodeficient patients. It is also capable of integrating into the genome of the infected cell. Due to this, there can be a misdiagnosis between viral integration and active infection during laboratory diagnostics. Thus, determination of HHV 6 infection using proper laboratory tools is relevant. Also the data on viral interference of HHV 6 and other herpes viruses are very poor especially for patients with hematological malignancies. The aim of the study was to identify laboratory markers of HHV 6 and the form of infection in patients with hematological malignancies. Materials and methods. 98 patients with hematological malignancies positive for HHV 6 DNA during the infectious complication were enrolled in the study. Viral load in leukocytes and plasma of peripheral blood, antiviral M and G immunoglobulins and peripheral blood leukocytes count were evaluated. Results. The majority of patients (66 out of 98, 67.3%) showed laboratory signs of latent HHV 6. Integrated HHV 6 was suspected in 2 patients due to high viral load (1.5x105 copies and 1.7x105 copies), but it was not confirmed subsequently. Additional testing of HCMV and EBV in patients with laboratory signs of active HHV 6 infection revealed the superiority of monoinfection over mixed infection (20 of 32, 62.5%). In cases of mixed infection, the most common co-infectant was HCMV observed in 9 out of 12 (75%) cases. Mild leukopenia accompanied HHV 6 active infection. Conclusion. Laboratory signs of latent HHV 6 tend to be prevalent in patients with hematological malignancies. In patients with laboratory markers of active HHV 6, the monoinfection demonstrated the superiority over mixed one. In cases of mixed infection, HCMV appeared to be the most commonly co-infectant. No cases of an integrated form of HHV 6 have been observed. The viral load of HHV 6 in leukocytes and blood plasma is almost 3 times lower in patients with a mixed infection than with a monoinfection. Active replication of HHV 6 was accompanied with mild leukopenia.