We propose to investigate the viral genomic and host cell determinants of in vivo pathogenicity by HIV by studying viral genomic diversity in relation to immunologic and clinical state, T helper cell numbers, host range, and in vitro cytopathology. A large fraction of HIV-infected individuals are clinically well; some have completely normal T cell subset profiles. It has been shown that the development of AIDS-related diseases is correlated with decreased numbers of T helper cells, which most likely is a reflection of progressive immunodeficiency from HIV- induced cytopathology. Different isolates of HIV isolated mainly from patients with AIDS or ARC show striking genomic heterogeneity. Some strains of HIV-related retroviruses such as STLV III AGM and HTLV IV are not associated with clinical disease. In order to understand better the mechanism of in vivo cytopathology and pathogenesis by HIV, we plan to clone molecularly the genome of HIV strains from 5 clinically well individuals with normal T cell subset profiles. We then shall characterize the clones by restriction endonuclease analysis and infectivity assay as well as sequence the infectious clones, and compare these sequences with sequenced isolates of HIV-1, STLV III, HTLV IV, and HIV-2. In addition, we shall clone the CD4+ lymphocytes from these 5 individuals and study their ability to replicate prototype HIV-1 as well as their own isolate to determine if the lack of in vivo cytopathology is a function of their CD4+ lymphocytes; the absence of cytopathology in these individuals may be secondary to their viral isolates, CD4 lymphocytes other aspects of host defenses, or a combination of these factors. We shall also compare the host range properties and in vitro cytopathology of the isolates we obtained from these well individuals with those of prototype HIV-1 strains to understand better the lack of in vivo cytopathology in the isolates obtained from well individuals with normal T cell subset profiles. The 5 individuals will be followed every 6 months with detailed immunologic and clinical evaluations and serial HIV isolations. The genomes of the serial isolates will be compared to determine if changes in genomic structure can be correlated with changes in clinical and immunologic status, T helper cell numbers, host range, and in vitro cytopathology.
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