Cystamine Inhibits HIV Type 1 Replication in Cells of Monocyte/Macrophage and T Cell Lineages

The effects of cysteamine (2-aminoethanethiol, MEA) and its disulfide, cystamine, on the human immunodeficiency virus (HIV-1) expression in chronically infected promonocytic cells (U1), T cell line (ACH-2), and peripheral blood monocyte-derived macrophages (MDM) were investigated. U1 and ACH-2 cells constitutively express low levels of virus, which is increased by the addition of tumor necrosis factor (TNF-α), interleukin 6 (IL-6), granulocyte-macrophage-colony-stimulating factor (GM-CSF), and other inducers. Cystamine, in noncytotoxic doses, suppressed in a concentration-dependent fashion the induction of HIV-1 expression mediated by TNF-α, IL-6, GM-CSF, and monokine-enriched monocyte culture supernatants in both U1 and ACH-2 cells as determined by HIV-1 reverse transcriptase (RT) activity. Similarly, HIV-1 expression was substantially reduced in the cystamine-treated primary MDM cultures compared with the untreated control cultures. The addition of cystamine into HIV-1 chronically infected MDM (12 days after infection was established) also suppressed 80-90% of RT activity in comparison to the untreated controls. HIV-1 (Bal) infected MDM cultures (without cystamine treatment) demonstrated giant syncytium formation, whereas cystaminetreated cultures lacked the giant syncytia induced by HIV-1 infection. Cystamine also inhibited LPS-induced TNF production in MDM. In contrast to cystamine, cysteamine showed no significant effects on either the monokine-induced HIV-1 expression in U1 or ACH-2 or acute and chronic HIV-1 infection in MDM. Thus, these observations indicate that cystamine may have the potential to limit HIV-1 replication in T cells and MDM in vivo and may be a member of new class of drugs with anti-HIV-1 effects.