DESIGN OF MINI-GENES AS DNA VACCINES FOR HIV THERAPY

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Vaccination has had a profound effect on the prevention and control of infectious disease for centuries. Injection of attenuated live or dead viruses, generates specific humoral and cellular immunity, and importantly, induces immunological memory. This protects an individual when challenged later by the pathogenic virus. Recently, administration of single recombinant viral proteins to generate immunity has met with limited success. No vaccine exists to combat human immunodeficiency virus (HIV-1). This is because the virus infects and cripples T lymphocytes and macrophages which are critical regulators of specific immunity. Increasing evidence suggests that protein products of the virus are themselves harmful to cells not only in the periphery, but also in the brain. For example, the envelope protein of the virus, called gp12O, even in the absence of infection, can mediate toxic effects in the brain which resemble those observed in AIDS dementia complex (ADC). Injection of DNA encoding complete viral proteins is an exciting and successful new method for vaccination. In this proposal, we will judge the efficacy for CTL generation of designing mini-gene DNA vectors encoding minimal viral epitopes, with and without signal sequences, in the presence and absence of T helper epitopes as well as assess the costimulatory effects of the cytokines IL-2 and IL- 12, on CTL induction. This approach ensures that animals are not exposed to entire viral proteins with their potential deleterious effects. This model system will lay tide foundation for the development of a general strategy for creating vectors containing multiple viral epitopes which can be used to generate immunity in human populations. In this proposal, we plan four Specific Aims: (1) to design vectors for DNA vaccination encoding only animal peptide sequences required to generate gp120-specific cytotoxic T cells (CTLs) in mice; (2) to examine the role which CD4+ T helper cells play in the induction of these gp120- specific CTLs; (3) to determine whether CTL generation can be enhanced by coinjection of a cytokine expression vector, either IL-2 or IL- 12, together with the vector encoding the gp120 CTL epitope; (4) in collaboration with Dr. L. Mucke (Scripps), to assess the effect that gp120-specific CTLs have on the brains of transgenic mice expressing gp120 specifically in astrocytes.