engleski

Intracellular Immunization of Human Immunodeficiency Virus

There is, at present, no effective anti-HIV treatment available that is specifically and selectively toxic to HIV infected cells. This communication describes an approach to treatment of HIV infection that is based on selective and specific toxicity only to HIV infected cells. Hence, we constructed the replication-defective HIV genomes that are designed to function as rapidly acting genetic traps. These HIV genomes are replication-defective because sequences coding for tat and nef have been deleted and replaced by others coding for diphtheria toxin A fragment (DT-A). When assayed by transfection in cell culture, plasmids carrying the modified HIV genomes completely abort the growth of wild type HIV in susceptible cells (HeLa CD4LTRb-gal). To apply these genetic traps under in vivo conditions, they would need to be presented in the form of HIV virions, capable of specifically and selectively infecting macrophages and T-lymphocytes, the usual targets of HIV infection. Production of such modified virions would, however, require cell lines that are totally resistant to DT-A. We undertook the construction and characterisation of such cell lines, based on engineering resistant forms of DT-A's specific substrate - protein elongation factor EF-2; histidine residue 715 in EF-2 ( that is modified to diphtamide) was replaced by glutamine, methionine, asparagine or leucine which are incapable of serving as substrates for DT-A toxic effects. Cell lines containing such mutated forms of EF-2 show at least ten fold higher resistance to DT-A than the parent cells. Whether or not these cell lines are capable of supporting the multiplication of virions encoding DT-A, remains to be determined.

HIV; genetic trap; intracellular immunization

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