[Detection of viral particles in the blood lymphocytes of a patient with T-cell acute lymphoblastic leukemia]. / Vyiavlenie virusnykh chastits v limfotsitakh krovi bol'nogo T-kletochnym ostrym limfoblastnym leikozom.

The electron microscopic examinations of the short-term cultures of mononuclear cells from patients with T-cell acute lymphoblastic leukemia were conducted for the detection of viral particles. The viral particles which correspond in their morphology to C type retroviruses are observed in the intercellular space of the culture.

[Exposure of the major immunodominant epitope of the gp51 envelope protein of bovine leukosis virus on the surface of the hepatitis B core antigen capsid]. / Eksponirovanie mazhornogo immunodominantnogo épitopa obolochechnogo belka gp51 virusa leikoza krupnogo rogatogo skota na poverkhnosti kapsid kor-antigena virusa gepatita B.

Insertion of 48 amino acid long sequence of envelope protein gp51 of bovine leukemia virus (BLV), located from position 56 till 103 of mature protein, into Pro144 position of hepatitis B core antigen (HBcAg) leads to the formation of chimeric capsids. These capsids preserve morphology of intact HBcAg but expose on their outer surface BLV epitopes which are localised in the inserted gp51 fragment and responsible for the recognition of chimeras by monoclonal anti-gp51 antibodies MAK14. The anti-genicity of gp51 epitopes within chimeric capsids is not disturbed after shortening of C terminal part of inserted gp51 fragment by deletion of amino acids 73-103. The resulting chimeras show the same capsid-forming ability as well as HBcAg and gp51 antigenic properties.

[Isolation of the core of Dane particles from donor blood]. / Vydelenie serdtseviny chastits Deina iz krovi donorov.

Ultracentrifugation in a flow rotor was used for partial purification and concentration of Dane particles from the plasma of donors, carriers of HBsAg. Subsequent purification was achieved by centrifugation in sucrose and cesium chloride density gradients. The iodinized inner component of Dane particles formed a peak in the zone of density typical of HBsAg localization. The specificity of the antigen was confirmed by the radioimmunologic method.

[Experimental induction of lympholeukemia in calves by a purified preparation of bovine leukemia virus]. / Eksperimental'noe vosproizvedenie limfoleikoza u teliat preparatom ochishchennogo virusa leikoza krupnogo rogatogo skota.

The leukemogenic properties of bovine leukemia virus (BLV), isolated from blood plasma, milk and short-term cultures of blood-circulating leukocytes were studied. A complex life-time examination of 14 calves inoculated with a preparation of BLV established leukemia in 4 animals; it was suspected in 3 calves. By the present time leukemia has been morphologically established in 6 out of 13 calves and one was a suspect. Positive results point directly to the viral etiology of bovine leukemia.

[Detection of HTLV-I virus in patients with myeloproliferative hemoblastoses]. / Vyiavlenie virusa HTLV-I u patsientov s mieloproliferativnymi gemoblastozami.

An association of HTLV-I virus with myelomonocytic leukemia was established by serologic and molecular-biologic procedures. Antibodies to one or two HTLV-I proteins were identified in 10 out of 30 patients with myelomonocytic leukemia; both antibodies to certain HTLV-I proteins and an integrated provirus were detected in 3 cases. Upon examination of donor blood, antibodies to one or two HTLV-I proteins were found in 0.8% cases, but only 0.3% of the examined donors were found positive to HTLV-I. This finding points to the presence of said virus in the population of Latvia.

Induction of bovine leukemia C-type oncornaviruses.

The data are presented concerning the induction of bovine leukemia with purified and concentrated C-type oncornaviruses isolated from cattle of Latvian Brown breed with persistent lympholeukemia. The calves induced with C-type oncornaviruses were found to have early signs of persistent lympholeukemia. Pathohistological changes suggesting persistent lympholeukemia were observed to precede early clinical and hematological signs of the disease. C-type oncornaviruses were reisolated from blood plasma of calves with experimentally induced lympholeukemia.