HTLV type 1 tax transduction in microglial cells and astrocytes by lentiviral vectors

Infection with human T cell leukemia virus type 1 (HTLV-1) can result in th e development of HAM/TSP, a nonfatal, chronic inflammatory disease involvin g neuronal degeneration and demyelination of the central nervous system, El evated levels of the proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and IL-1 observed in the cerebrospinal f luid of HAM-TSP patients suggest that cytokine dysregulation within the CNS is involved in neuropathogenesis. HTLV-1 infection and enhanced expression of TNF-alpha by microglial cells, astrocytes, and macrophages has been hyp othesized to lead to the destruction of myelin and oligodendrocytes in the CNS, Although the association of HTLV-2 infection and development of neurol ogical disease is more tenuous, HTLV-2 has also been found to be associated with peripheral neuropathies, To investigate the roles of HTLV Taxi and Ta rt in the induction of cytokine disregulation in these cell types, we are c urrently developing gene delivery vectors based on human immunodeficiency v irus type-1 (HIV-1) capable of stably coexpressing the HTLV-1 or -2 tax and eGFP reporter genes in primary human cells. Transduction frequencies of up to 50%, as assessed by eGFP expression, can be achieved in human monocyte- derived macrophages and in explanted cultures of human microglia, Prelimina ry data suggest that Taxi expression is sufficient to up-regulate the proin flammatory cytokine profile in explanted human microglial cells. Future exp eriments will compare and evaluate the effect of tax(1) and tax(2) gene exp ression on the cellular proinflammatory cytokine expression profile, as wel l as demonstrate the effects of transducing human fetal astrocytes and PBMC -derived macrophages.