Mechanisms of Protective Actions of Specific Antibodies against the Tick-Borne Encephalitis Virus

The subdivision of the viral population into subtypes and clusters based on the molecular genetic characteristics of the tick-borne encephalitis virus (TBEV) strains predetermines not only the differences in the biological properties of these strains, but also their different responses to specific antibodies in persons vaccinated against TBE.The aim of the present study is to show the differences in biological properties on the model of two strains of Far Eastern TBEV subtype belonging to different clusters and to substantiate the need for a personalized approach to the vaccine prophylaxis of tick-borne encephalitis.Results. Two strains of TBEV were used in the studies. On the basis of full genome sequencing the Dal’negorsk strain (FJ402886, GenBank) is referred to the typical representative of Sofjin-like, and Primorye-437 (JQ825162, GenBank) – to Oshima-like TBEV strains of the Far Eastern subtype.The experiment shows the levels of specific antibodies capable of neutralizing virulence strains of tick- borne encephalitis virus. Low antibody titers (1:100 and 1:400) can neutralize only a low dose of a non-virulent strain of tick-borne encephalitis virus. Reliable protection against the disease of people infected with virulent strains of the TBEV can provide only a high level of specific antibodies.Conclusion. If the level of specific antibodies of IgG is 1:400 or lower, the vaccination course should be continued, at a titer of antibodies above 1:400, revaccination can be postponed subject to annual monitoring of specific immunity parameters in the pre-epidemic TBE season.

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Comprehensive assessment of specific antibodies on infectious activity of tick-borne encephalitis virus

Russian Journal of Infection and Immunity ◽

10.15789/2220-7619-2019-3-4-559-567 ◽

2019 ◽

Vol 9 (3-4) ◽

pp. 559-567

Author(s):

G. N. Leonova ◽

O. S. Majstrovskaya ◽

V. A. Lubova ◽

N. B. Sanina

Keyword(s):

Ex Vivo ◽

Experimental Studies ◽

Encephalitis Virus ◽

Virus Elimination ◽

Specific Antibodies ◽

Tick Borne Encephalitis ◽

Antibody Titers ◽

Tick Borne Encephalitis Virus

Vaccines for prophylactic immunization provide the most reliable and effective protection against the vast majority of infectious diseases. Tick-borne encephalitis (TBE) represents a high-priority medical issue at the territory of the Eurasian continent. Of great importance is assessing a role of distinct antibody titers especially low titers, observed quite often in vaccinated individuals, sometimes posing obstacles in determining a threshold of seropositivity as well as the level of specific protection against TBE virus. We aimed at obtaining data to assess antiviral activity of virus-specific antibodies with distinct titer levels based on the in vitro, ex vivo and in vivo experimental studies with a highly virulent Far-Eastern strain of tick-borne encephalitis virus. The in vitro, ex vivo and in vivo comprehensive experimental studies with a highly virulent Far-Eastern strain of tick-borne encephalitis virus (TBEV) were conducted and the dynamics of antiviral activity of virus-specific antibodies at variable titers (1:100–1:3200) was measured (timeframe ranged within 1–96 hours p.i.) to provide a rationale for evaluating the antiviral immune response. It was found that the in vitro experiments demonstrated that the IgG at 1:100 titer exerted a weak anti-TBEV neutralizing effect at all time-points examined. The IgG 1:400 titer caused a 2 log PFU/mL decline in TBEV Dal strain yield at 72 h post-infection, whereas at 1:3200 titer it completely suppressed TBEV replication throughout the observation period. The ex vivo experiments with blood serum obtained from vaccinated subjects demonstrating a range of TBEV antibody titers (sera from vaccinated individuals with varying anti-TBEV antibody titers) and in vivo (outinbred white mice) experiments revealed a delayed virus elimination for antibody titers at 1:100 and 1:200 as well as rapid virus elimination (1–2 days p.i.) for antibody titers greater than 1:400. Thus, antibody titer at 1:400 may be considered as the universal anti-TBEV protection threshold. In order to properly conclude regarding the revaccination schedule it is advised to start with testing blood serum for durability of anti-TBEV immune response. Subjects with TBEV antibody titers at 1:100 and 1:200 should be strongly recommended to undergo a mandatory revaccination. Such an approach is believed to be the most effective way toward enhancing efficacy of vaccine-mediated protection against TBE.

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A solid-phase radioimmunoassay for quantitative measurement of class-specific antibodies against tick-borne encephalitis virus

Journal of Virological Methods ◽

10.1016/0166-0934(82)90036-2 ◽

1982 ◽

Vol 3 (6) ◽

pp. 319-328 ◽

Cited By ~ 4

Author(s):

W. Frisch-Niggemeyer

Keyword(s):

Quantitative Measurement ◽

Solid Phase ◽

Encephalitis Virus ◽

Specific Antibodies ◽

Tick Borne Encephalitis ◽

Solid Phase Radioimmunoassay ◽

Tick Borne Encephalitis Virus

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TBE in South Korea

Tick-borne encephalitis - The Book ◽

10.33442/978-981-14-0914-1_12b-31 ◽

2019 ◽

Author(s):

Joon Young Song

Keyword(s):

South Korea ◽

Human Case ◽

Encephalitis Virus ◽

Surveillance Studies ◽

Tick Borne Encephalitis ◽

Tick Borne Encephalitis Virus

Although no human case of tick-borne encephalitis (TBE) has been documented in South Korea to date, surveillance studies have been conducted to evaluate the prevalence of tick-borne encephalitis virus (TBEV) in wild ticks.

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