(1) These observations suggest that Langat-like virus-based vaccines may not represent the most effective means to achieve protection against tick-borne encephalitis virus.
(2) The clinical and immunological events in volunteers following administration of 5 and 6 dex newborn mouse intracerebral LD5O (NmicLD5O) of the E5 "14" virus clone, segregated from the Langat TP21 E5 strain (tick-borne encephalitis-TE-complex) and propagated in 7 days old SPF chick embryos, are reported.
(3) The data strongly suggest that lead increased mortality following infection by complex means, the most important being the enhacement of encephalitogenic potential of Langat virus.
(4) The Skalica virus has been compared with Hypr and Langat viruses by kinetic haemagglutination-inhibition (HI) test.
(5) The median survival time 8 days after intracerebral injection of Langat virus increased to 10 days with an immunosuppressive course of cyclophosphamide, with concomitant reduction in the inflammatory response.
(6) a single dose of live attenuated Langat (E5 "14") virus of the tick-borne encephalitis (TBE) complex.
(7) The course of plaque segregation from the Langat E5 strain of the E5 "14" clone is described.
(8) TBE virus grown in the presence of ammonium chloride as well as Langat virus purified from the supernatant of infected chick embryo cells contained the precursor of protein M (prM) rather than M itself.
(9) Sequence analysis confirmed this distinctiveness and proved that the vaccine strain Yelantsev was also Langat virus.
(10) A study was also made of the genetic stability and basic biological properties of pathogenic and non-pathogenic clones of the Langat virus.
(11) Under the conditions of hypokinesia (or changes in temperature), the death rate among the animals infected with langat virus has been found to increase 3- to 4-fold in comparison with the controls, the mortality level in the groups subjected to different stress factors being the same.
(12) Nevertheless, it was possible to differentiate the Skalica strain from Langat, louping-ill and Omsk haemorrhagic fever (OHF) viruses by ELISA when monoclonal antibodies and antigens were diluted 1:10,000.
(13) Using Hypr antigen, differences were observed between Skalica, Hypr, and Langat viruses.
(14) By these criteria Skalica virus proved to be distinct from TBE virus and to be very closely related to Langat virus, differing by only two bases among a total of 416 nucleotides compared.
(15) It has been shown by adoptive transfer that administration of Langat-virus-induced autoreactive lymphocytes (ARL) to the syngeneic recipient is followed by accumulation of autoreactive effectors (AE) eliciting a graft-verus-host reaction (GVHR) in the syngeneic system (AEgvhr).
(16) In the thymus of mice infected with Langat virus T-suppressors (TS) inhibiting the differentiation of PARTL into ARTL have been detected.
(17) Langat virus, a member of the family Flaviviridae is antigenically very similar to highly pathogenic tick-borne encephalitis viruses.
(18) The intensity of infection of immunocompetent organ cells with tick-borne encephalitis and Langat viruses in mice with temporary immunodeficiency induced by cyclophosphane is characterized.
(19) Mice inoculated intraperitoneally with the alphavirus Semliki Forest were protected against a subsequent challenge with the flavivirus Langat.
(20) Attenuated Langat E5 virus has potential value for live virus vaccine for the protection against human illness caused by the members of the Russian spring-summer virus complex.