Localization of HTLV-1 and HIV-1 proviral sequences in chromosomes of persistently infected cells.

Integration sites for HTLV-1 and HIV-1proviruses were detected by FISH on the chromosomes of HTHIV27 cells persistently infected by HIV-1 (strain IIIB). HTLV-1 signals were found on 9 loci of chromosomes 4, 6, 9, 15 and 16. Integration sites of GC-rich HTLV-1 provirus are located in GC-rich isochores, confirming an 'isopycnic' integration, namely an integration in which the GC level of the host sequences around the integration site match the GC level of the provirus. This conclusion is not only derived from the compositional map of human chromosomes, but also from HTLV-1 hybridization on compositional fractions of human DNA. Integration of GC-poor HIV-1 provirus was found on 4 loci of chromosomes 2, 7, 17 and 19. One copy of a complete HIV-1 provirus, which is active, was integrated in H1 isochores, whereas other defective copies were located in GC-poor L isochores. These results are discussed in terms of regional integration of retroviral sequences.

[The HTHIV27 highly productive continuous cell line and its use for solving the fundamental and applied problems of HIV infection]. / Vysokoproduktivnaia persistentnaia liniia kletok HTHIV27 i ee ispol'zovanie dlia resheniia fundamental'nykh i prikladnykh voprosov VICh-infektsii.

For the first time the detailed description of continuous cell line HTHIV27, remaining stable for more than 10 years, has been made. The stability of all biological characteristics and high productivity of the strain has made it possible to use it as a HIV producing strain for the construction of a diagnostic test system for the detection of antibodies to HIV. The lysate obtained on the basis of HIV producing cells HTHIV27 has been shown to possess a number of advantages in comparison with the analogous system based on lytically infected cells. On the basis of strain HTHIV27 an in vitro cell system for the analysis of the specific activity of chemotherapeutic preparations intended for the inhibition of HIV has been developed. The use of this newly obtained continuous cell line HTHIV27 has been shown to permit the evaluation of the antiviral activity of compounds, characterized by different molecular mechanisms for the suppression of viral activity.

[Immunocytophotometric and cytogenetic analyses of T-lymphoblastoid cell lines in experimental HIV Infection]. / Immunotsitofotometricheskii i tsitogeneticheskii analiz kletok T-limfoblastoidnykh linii pri éksperimental'noi VICh-infektsii.

The accumulation of viral proteins p24 and gp41 in MT-4 cells was shown to occur asynchronously. No increase in the number of polydiploid cells, no polyploid mitoses or chromosome defects were found indicating the antiproliferative effect of HIV on MT-4 cells. A cyclic pattern of the infection course was observed in infected Jurkat-tat cells. The accumulation of viral proteins was concerted, their maximum amounts preceding the cell death. HIV-1 did not inhibit cell division and caused strong disorders in the chromosome structure.

[Localization of the CD4 receptor gene in the chromosomes of clone cells of the monocytoid line U-937 characterized by different sensitivities to HIV]. / Lokalizatsiia gena retseptora CD4 v khromosomakh kletok klonov monotsitoidnoi linii U-937, kharakterizuiushchikhsia razlichnoi chuvstvitel'nost'iu k VICh.

Karyotypes of two clones of U-937 line, with high and low sensitivity to HIV-1, were studied. The CD4-receptor gene-cellular receptor of HIV-1 was mapped. CD4-receptor gene was located according to in situ hybridization method, in locus 12 p11-p12, both in cells of high-sensitive clone U-937/16, and in cells of low-sensitive clone U-937/4. It is determined that in both the clones chromosomes 12 are presented in two copies and are not affected by rearrangements. That allows to conclude that the sensitivity of cells U-937 to HIV-1 does not depend on the dose of this gene, or on its transference in chromosomes.

Cytogenetic analysis of human hepatocarcinoma cell line PLC-PRF-5 and its mutant clones with different degrees of cell differentiation.

A detailed analysis was made of the karyotype of human hepatocarcinoma cell line PLC-PRF-5 containing an integrated hepatitis B viral genome and 10 mutant clones derived from the line. These clones are drug resistant and display features of cell differentiation. Cytogenetic manifestations of gene amplification common to many cells resistant to drugs were not observed in these clones, but certain tendencies of karyotype evolution involving material from chromosomes 7 and 11, as well as chromosomes 5 and 15, were recorded for a group of cytostatic-resistant clones. An increase in polyploid cell number and number of cells with chromosome pulverization as compared with the original line was noted in the clones. This phenomenon may be related to the cytopathic effect of the hepatitis B viral proteins, which have a higher expression in the clones.

[The use of DNA hybridization in situ for identifying chromosomal rearrangements in the karyotyping of cell lines]. / Ispol'zovanie gibridizatsii DNK in situ dlia identifikatsii khromosomnykh perestroek pri kariotipirovanii kletochnykh linii.

A complex karyological analysis of three human cell lines (PLC-PRF-5, MT-4 and U937) was carried out that involved traditional methods of G-, C-banding and silver staining, in addition to the in situ hybridization technique using 4 alpha-satellite DNA probes: DNA specific for centromeric regions of chromosome 11, 6, 13, and 21, and 14 and 22. The application of this additional method allowed to identify, prove or detalize the structure of 13 markers in PLC-PRF-5 cells, 1 marker in MT-4 cells, and 3 markers in U937 cells. The results show that the in situ hybridization method would be successful in cell line karyotyping for a more objective identification of some markers difficult for analysis.

Karyological approach to the identification of true cell lines susceptible to the human immunodeficiency virus (HIV).

A karyological analysis of twenty-two variants of eight cell lines, which differed in their susceptibility to the human immunodeficiency virus (HIV) and which had been obtained from different sources, was carried out by means of differential chromosome staining for G and C bands. The karyotypes of eight T-lymphoblastoid cell lines were identified, including five (MT-4, Molt-3, CEM, H-9, and Hut-78) not previously studied by cytogenetic methods. Karyotyping confirmed the identity of seventeen variants of the eight cell lines, and five variants of four lines were found to be misidentified. Comparative analysis of the cytogenetic characteristics of the three CEM-line variants demonstrates the need for karyotype evaluation in the course of in vitro cell cultivation. Fourteen identical marker chromosomes were revealed in H-9 and Hut-78 cell karyotypes, confirming the common origin of these two lines. It was found that the cells of the HIV-susceptible lines had a tendency to undergo polyploidisation both during the initial stages after isolation and in the course of cultivation.

[The RH-PA cell line--a source for obtaining the urokinase-type plasminogen activator]. / Kletochnaia liniia RH-PA--istochnik polucheniia aktivatora plazminogena urokinaznogo tipa.

A new cell line (RH-PA) was established on the basis of the human embryonic kidney cell line (RH). The new line produces urokinase type plasminogen activator (PA). The activity of the activator amounted to 150-200 IU/ml estimated with the procedure of fibrin plates. Morphological types of the RH-PA and RH cells were studied and their comparative karyologic analysis was performed. The growth curves of the cells are presented and the dynamics of PA accumulation by them in the maintaining medium is described. Optimal conditions for cultivating the RH-PA cells providing maximum production of the PA were developed.