VIRUS-CELL INTERACTIONS AND HOST FACTORS IN HIV PATHOGENESIS

在U1细胞系中激活潜伏的HIV基因组作为一种检测方法

The activation of a latent HIV genome in the U1 cell line was used as a model to study cellular pathways involved in viral replication. Specifically, several chemical carcinogens and environmental mutagens were examined for their ability to induce virus from this cell line also with the objective of identifying risk factors of physiologic relevance that may affect disease progression in AIDS. Enhanced virus production, measured by RT, p24 and PCR analysis, was seen in cells treated with benzopyrene, NNK and aflatoxin B. Viral induction was accompanied by an increase in NF-KB activity and production of cytokines such as TNF-alpha. In the case of aflatoxin, virus induction appeared to be a TNF-a independent mechanism. We are investigating the effects of these agents on signal transduction pathways related to T cell function and activation i.e. phosphorylation, JAK-STAT kinases, and production of cytokines other than TNFa and IL-6 and apoptotic mechanisms that may enhance virus production. Future studies will focus on BP and NNK. The in vivo significance of these findings will be investigated using alveolar macrophages as a model system. In a separate effort, the phenomenon of viral interference will be studied with the goal of identifying cellular pathways using HIV-1 superinfection of HIV-2 infected cells and vice versa. From epidemiologic studies it is known that HIV-2 infection can confer some degree of protection against HIV-1 infection. It will be of interest to identify cellular pathways that may be common to both types of phenomena (i.e. induction and interference). These approaches should enhance our understanding of virus-cell interactions and their impact on viral replication. In vivo studies involving patients from various risk groups who are rapid (RP) or slow progressors (SPs) and some in the early phase of infection have been initiated where virus burden will be evaluated by quantitative PCR and culture. Virus isolated from some RPs, SPs and early seroconverters will be subject to nucleotide analysis in the LTR, gag(p24), RT and env regions. The tropism, pathogenicity and immunological profile of a few selected isolates from RP, SP and patients with primary HIV syndrome will be studied in vitro in T cells and monocytes and in a small animal model. These studies are expected to provide some insights into the biology of isolates in progressive vs. non progressive and in primary HIV infection (early seroconversion).