[A comparative characteristic of antigenic properties of recombinant and native hbs-antigens with G145R mutation and evaluation of their immunogenicity]

New Russian Trivalent Hepatitis B Vaccine (Bubo®­-Unigep): Reactogenicity, Safety and Immunological Efficacy

Relevance. In Russia, phase III of clinical trials of the domestic trivalent vaccine Bubo®-Unigep, containing protective antigens that provide protection against “wild” forms of the hepatitis B virus subtypes ay and ad, as well as the determinant of serotype ay with the G145R mutation, has been completed. Аim. Evaluation of the effect of the new recombinant polyvaccine against hepatitis B «Bubo-Unigep» on vital functions and laboratory parameters in previously unvaccinated individuals in an adult healthy population. Materials and methods. A randomized multicenter clinical study was conducted to assess the reactogenicity, safety and immunogenicity of Bubo®-Unigep (CJSC NPC «COMBIOTECH») in previously unvaccinated healthy adults (n = 166). The study performed according to the protocol developed by the contract research organization «R&D Pharma» at eight clinical centers located in Russian Federation. Results and discussion. Analysis of the studied parameters throughout the study (frequency and severity of adverse events, physical examination data of volunteers with assessment of vital signs, laboratory test results, etc.) made it possible to establish a high safety profile of Bubo®-Unigep vaccine, which turned out to be virtually areactogenic without causing development of targeted local and systemic post-vaccination adverse events. Conclusion. The wide range of specificity of the immune response, along with the high safety and reactogenicity of the Bubo®-Unigep vaccine, the production of which can be carried out through a full technological cycle without the use of imported substances, will increase the effectiveness of hepatitis B prevention.

[Identification by enzyme immunoassay of escape mutants S143L and G145R of hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus)]

INTRODUCTION

The achievement of the goal of the World Health Organization to eliminate viral hepatitis B by 2030 seems to be problematic partly due to the presence of escape mutants of its etiological agent, hepatitis B virus (HBV) (<i>Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus</i>), that are spreading mainly in the risk groups. Specific routine diagnostic assays aimed at identification of HBV escape mutants do not exist.The study aimed the evaluation of the serological fingerprinting method adapted for routine detection of escape mutations in 143 and 145 aa positions of HBV surface antigen (HBsAg).

MATERIAL AND METHODS

HBV DNA from 56 samples of HBsAg-positive blood sera obtained from donors, chronic HBsAg carriers and oncohematology patients has been sequenced. After the identification of mutations in HBsAg, the samples were tested in the enzyme-linked immunosorbent assay (ELISA) kit «Hepastrip-mutant-3K».

RESULTS AND DISCUSSION

Escape mutations were detected mainly in patients with hematologic malignancies. Substitutions in 143 and 145 aa were found in 10.81% and in 8.11% of such patients, respectively. The G145R mutation was recognized using ELISA kit in almost all cases. The kit specifically recognized the S143L substitution in contrast to the S143T variant. The presence of neighbor mutation D144E can be assumed due to it special serological fingerprint.

CONCLUSION

ELISA-based detection of escape mutations S143L, D144E and G145R can be used for routine diagnostics, especially in the risk groups. The diagnostic parameters of the kit can be refined in additional studies. This immunoassay and methodology are applicable for the development and quality control of vaccines against escape mutants.

Recombinant HBsAg of the Wild-Type and the G145R Escape Mutant, included in the New Multivalent Vaccine against Hepatitis B Virus, Dramatically Differ in their Effects on Leukocytes from Healthy Donors In Vitro

Immune-escape hepatitis B virus (HBV) mutants play an important role in HBV spread. Recently, the multivalent vaccine Bubo®-Unigep has been developed to protect against both wild-type HBV and the most significant G145R mutant. Here, we compared the effects of recombinant HBsAg antigens, wild-type and mutated at G145R, both included in the new vaccine, on activation of a human high-density culture of peripheral blood mononuclear cells (PBMC) in vitro. The antigens were used either alone or in combination with phytohemagglutinin (PHA). None of the antigens alone affected the expression of CD40, HLA-DR or CD279. Wild-type HBsAg enhanced CD86 and CD69 expression, and induced TNF-α, IL-10, and IFN-γ, regardless of the anti-HBsAg status of donor. In the presence of PHA, wild-type HBsAg had no effect on either of the tested surface markers, but increased IFN-γ and IL-10 and inhibited IL-2. In contrast, the G145R mutant alone did not affect CD86 expression, it induced less CD69, and stimulated IL-2 along with lowering levels of TNF-α, IL-10, and IFN-γ. The G145R mutant also suppressed PHA-induced activation of CD69. The dramatic differences in the immune responses elicited by wild-type HBsAg and the G145R mutant HBsAg suggest distinct adaptive capabilities of the G145R mutant HBV.