Browsing by Author "Becker, M. L. B."

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    Isolation of a lymphadenopathy-associated virus from a patient with the acquired immune deficiency syndrome
    (Health & Medical Publishing Group, 1985) Becker, M. L. B.; Spracklen, F. H. N.; Becker, W. B.
    A virus similar to the lymphadenopathy-associated virus or human T-lymphotropic virus type III, which has been described in association with the acquired immune deficiency syndrome (AIDS) by several laboratories elsewhere in the world, was isolated from a Cape Town patient with lymphadenopathy and acquired immune deficiency. This virus has the characteristic morphogenesis and ultrastructure and its genome encodes the virus-specific p24 protein. It is T-lymphotropic and produces the characteristics cytopathic effect. It can be serially propagated in a human lymphocyte line of T4+ phenotype. This isolate is being used in diagnostic immunofluorescence assays for virus-specific antibodies.
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    Isolation of a new human herpesvirus producing a lytic infection of helper (CD4) T-lymphocytes in peripheral blood lymphocyte cultures. Another cause of acquired immunodeficiency
    (Health & Medical Publishing Group, 1988-12) Becker, W. B.; Engelbrecht, S.; Becker, M. L. B.; Piek, C.; Robson, B. A.; Wood, L.; Jacobs, P.
    A new human helper (CD4) T-lymphotropic herpesvirus (HTLHV) was first isolated in February 1985 from the cultured peripheral blood lymphocytes (PBL) of a patient with the acquired immunodeficiency syndrome, and subsequently from the PBL of 1 patient with hairy cell leukaemia and 2 patients with lymphoproliferative disease associated with human T-lymphotropic virus type I infection. The viruses could be serially subcultured in umbilical cord PBL cultures in which they infected helper (CD4) T-lymphocytes producing multinucleate giant cells with intranuclear inclusions followed by cell lysis. Electron microscopy of infected cultures revealed that the isolates were herpesviruses. Specific DNA probing showed that the 4 isolates were related to one another but were distinct from cytomegalovirus, Epstein-Barr virus, Herpes-virus hominis types 1 and 2, and varicella-zoster virus. HTLHV lyses the same target cell as human immunodeficiency virus in PBL cultures suggesting that it may have a similar potential to cause acquired immune deficiency. The development of an unequivocally diagnostic serological test is a priority, so that the epidemiology and pathogenesis of HTLHV infection can be studied.
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    Isolation of human T-lymphotropic virus type I (HTLV-I) from a black South African with Kaposi's sarcoma
    (Health & Medical Publishing Group, 1988) Becker, W. B.; Botha, M. C.; Engelbrecht, S.; Becker, M. L. B.
    Serological evidence for HTLV-I infection in the South African population has now been confirmed by the isolation of the virus from the peripheral blood lymphocytes of an adult Tsonga male. The subject was an indigenous black man from the south-eastern Transval who had suffered from Kaposi's sarcoma for a decade and in whom serum antibodies against HTLV-I were demonstrated. T-lymphocyte cell lines were established from his peripheral blood lymphocytes and shown to be productively infected with HTLV-I as evidenced by: the characteristic cell morphology; the typical morphogenesis on ultrathin section electron microscopy; the viral genome in DNA extracted from the cell lines; characteristic reverse transcriptase activity and viral specific proteins in the cell cultrue supernatant fluids. Spread of infection occurs through sexual intercourse, from mother to child, and by blood transfusion. Donated blood should be screened to contain the spread of HTLV-I infection.
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    Serum antibodies to human T-cell leukaemia virus type I in different ethnic groups and in non-human primates in South Africa
    (Health & Medical Publishing Group, 1985) Becker, W. B.; Becker, M. L. B.; Homma, T.
    The prevalence of humoral antibodies to human T-cell leukaemia virus type I (HTLV-I) was investigated in different ethnic groups and in non-human primates in South Africa. Serum antibody levels were determined by enzyme-linked immunosorbent assay (ELISA) using either disrupted whole HTLV-I or purified p24 core protein (p24 HTLV-I) as antigens. ELISA was complemented by direct radio-immunoprecipitation assays using either purified iodinated p24 HTLV-I or radiolabelled lysates of an HTLV-producing cell line as antigen followed by sodium dodecyl sulphate polyacrylamide gel electrophoresis of the immunoprecipitates, and by immunofluorescence using the HTLV-I-producing cell line HUT-102 as antigen. Antibodies were demonstrated in 3,5% of Asians, 3,5% of blacks and 4,1% of coloureds, but not in whites, and also in 29% of vervet monkeys and 33% of baboons. We conclude that HTLV-I or closely related viruses cause widespread infection in non-human primates in South Africa and in a lower percentage of humans, including apparently healthy blood donors. We are currently isolating retroviruses from seropositive reactors and investigating the possible relevance to disease in South Africa.