[Thymus hormones in the treatment and prevention of flavivirus infection under experimental conditions]. / Gormony timusa v lechenii i profilaktike flavivirusnoi infektsii v usloviiakh éksperimenta.

The evaluation and selection of the preparations of thymic hormones for the treatment and prophylaxis of acute tick-borne encephalitis (TBE) caused by Far Eastern TBE virus strains have been carried out on mice under different experimental conditions. These virus strains, highly and faintly virulent with respect to noninbred mice, produce a different modulating effect of the immune responsiveness of the host, respectively suppressing or simulating immune response to sheep red blood cells. A high prophylactic effect produced by thymic hormones (having protective index equal to 50-67%) with respect to highly virulent TBE virus stains has been established, which is seemingly indicative of the fact that such course of TBE leads to the formation of the state of severe immunodeficiency due to the lesion of the thymus. A high therapeutic effect resulting from the clinical use of thymic hormones is suggested.

[The degree of virulence in Far Eastern strains of the tick-borne encephalitis virus]. / Izuchenie stepeni virulentnosti dal'nevostochnykh shtammov virusa kleshchevogo éntsefalita.

Screening of immunomodulating properties of 45 tick-borne encephalitis (TBE) virus strains isolated in the southern part of the Soviet Far East was carried out. TBE virus strains were found to have different effects on the immune responsiveness of host splenocytes. Over 90% of the strains isolated from hematothermals could inhibit the immune response of the host to a heterologous antigen (sheep erythrocytes); similar properties were found in 5 strains isolated from ticks. At the same time, most strains isolated from the vectors were unable to modulate the immune response of antibody-producing cells and 3 strains even had immunostimulating properties. The existence of significant correlation (r = -0.57; p < 0.01) between the immunomodulating activity of a strain and peripheral virulence of the virus for white mice indicates that the immunomodulation parameter may be used as another pathogenetic marker. This marker and that of the peripheral activity served the basis for creation, by means of the mathematical method of discrimination analysis, of a new pathogenetic characteristic--a single marker of strain virulence.

[An assessment of the immunoepidemiological efficacy of a liquid cultured killed vaccine against tick-borne encephalitis virus strain 205 in the Maritime Territory]. / Otsenka immunoépidemiologicheskoi éffektivnosti zhidkoi kul'tural'noi ubitoi vaktsiny protiv kleshchevogo éntsefalita shtamm 205 v usloviiakh Primorskogo kraia.

Inactivated vaccine against tick-borne encephalitis (TBE), prepared on the basis of strain 205, is characterized by epidemiological (53%) and immunobiological activity. The appearance of a few TBE cases among the vaccinees is probably due to different maturation rate of immune response to various strains (different specificity of immune response). A suggestion has been made that no inactivated vaccine prepared from a single strain can produce a reliable protective effect because of pronounced heterogeneity of the population of TBE virus.

[A virulence study of tick-borne encephalitis virus strains isolated in the southern Soviet Far East]. / Izuchenie virulentnosti shtammov virusa kleshchevogo éntsefalita, izolirovannykh na iuge Sovetskogo Dal'nego Vostoka.

Study of virulence for white mice and Syrian hamsters of 115 tick-borne encephalitis virus strains isolated in Maritime Territory showed virulence to be a complex biological manifestation of pathogenic properties of tick-borne encephalitis virus. The virulent properties of strains may have individual manifestations in each species of specific causative agent hosts and susceptible experimental biological models.