Chapter category: Viruses
HIV-1 Tropism and Pathogenesis
HIV and Membrane Receptors
Edited by: Dimiter Dimitrov, Christopher Broder and Garry LynchISBN: 1-57059-464-3
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Chapter authors:
Dimitrov, Dimiter S., Christopher C. Broder
Genotypic and phenotypic variation is a hallmark of infection by HIV-1. The ability of HIV-1 to infect different types of cells varies from one isolate to the next and is referred to as cell-type tropism or cytotropism. HIV-1 cytotropism, cytopathicity and pathogenesis are in general correlated, but in many cases the relationships are complex, and may involve a variety of viral and host factors particularly those that regulate proviral gene expression. Of particular note is the marked difference in cytotropism of individual HIV-1 isolates in vitro; some isolates productively infect continuous CD4+ T-cell lines but not primary macrophages, whereas others show the opposite preference (reviewed in refs. 1-5). Cellular receptors play a major role in tropism and pathogenesis; infection of CD4+ cells by HIV-1 and their subsequent decline in their number, possibly due to CD4 interactions, is the hallmark of AIDS. Thus, the biological diversity of HIV-1, which reflects its cytotropic characteristics has critical implications for pathogenesis. In many cases, important determinants of cytotropism and pathogenesis have been mapped to the Env glycoprotein, and some of them involve interactions with CD4 and coreceptor molecules. This chapter will discuss HIV-1 tropism; reviewing the basis of cytotropism, how it now relates to the coreceptors for HIV-1 Env-mediated cell fusion and virus entry, and the implications on the pathogenesis of HIV- 1-induced disease. Recent reviews can be consulted for more details about the role of CD4 in tropism and pathogenesis
Additional chapters from this book:
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