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N L Letvin

Publications and source records attributed to N L Letvin.

259 records · Page 15Linked to original sources
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Report of a false-positive HIV test result and the potential use of additional tests in establishing HIV serostatus.

Considering the lifelong implications of a positive human immunodeficiency virus (HIV) test result, physicians should be aware of the limitations of tests for HIV. A 43-year-old man had a reactive enzyme-linked immunosorbent assay and an indeterminate result on Western blot analysis. The results of subsequent enzyme-linked immunosorbent assay and Western blot tests were interpreted as positive, and the patient was informed that he had HIV infection. Persistently undetectable plasma HIV-1 RNA, combined with normal physical examination findings, CD4(+) cell count, and CD4/CD8 ratio, prompted further testing, which revealed that the patient was not infected with HIV. False-positive HIV test results are uncommon, but they can occur. In the appropriate clinical setting, follow-up and the use of other laboratory tests, such as determination of plasma viral load, may help identify such cases.

AIDS Serodiagnosis↗
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Origins of HTLV-4.

Explore the source record for details and available documents.

Africa↗
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A novel epitope of the LFA-1 antigen which can distinguish killer effector and suppressor cells in human CD8 cells.

The CD4 subset of cells displays helper/inducer activity and recognizes class II antigens of the major histocompatibility complex (MHC), while the CD8 subset recognizes class I MHC antigens and exhibits cytotoxic or suppressor function. Considerable functional as well as corresponding phenotypic heterogeneity exists within the two major T cell subsets. Although the CD8+ population contains pre-cytotoxic, cytotoxic, pre-suppressor and suppressor effector T cells, these distinctions still rest largely on the use of functional assays. Attempts have been made to define the CD8+ precursor of the killer cell with new monoclonal antibodies. But more precise phenotypic distinctions between the functional subpopulations within CD8+ cells will be needed. We have now developed a monoclonal antibody, anti-S6F1 which can distinguish killer effector and suppressor effector cells in CD8 lymphocyte populations. The cell-surface structure defined by this antibody comprises two glycoproteins with relative molecular mass (Mr) 180K and 95K respectively. Also sequential immunoprecipitation studies and two dimensional gel electrophoresis indicate that anti-S6F1 recognizes a novel epitope on the LFA-1 antigen.

Animals↗
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Animal models for acquired immunodeficiency syndrome.

Substantial advances have already been made in the understanding of acquired immunodeficiency syndrome (AIDS). The major issues for AIDS research during the next few years must be practical ones: the development of a safe, effective vaccine for individuals not yet infected with the causative virus and the development of drug therapies for those already infected. Suitable animal models will be needed for studies designed to achieve these goals. Areas of investigation in animal models can be divided into four categories on the basis of increasing direct relevance to AIDS in humans: retroviruses that have no obvious, close relation to human immunodeficiency virus (HIV) but can induce chronic diseases with manifestations that include immunologic abnormalities; ungulate lentiviruses; HIV-related viruses of Old World primates; and HIV infection of chimpanzees. It is hoped that important research developments in experimental models can be quickly extrapolated to human AIDS.

Acquired Immunodeficiency Syndrome↗