The effect of iron overload on in vitro HIV-1 infection

Background: It has been shown that Fe is required by HIV-infected cells for production of viral particles. Excess iron in the cell is detrimental to the host but beneficial to the pathogen. Objectives: Here, we investigated the effect of excess Fe (overload) and chelation of the metal on in vitro HIV infection by assessing host cell responses (viability/death, stress protein expression and cytokine production) as well as virus replication (core protein content and enzyme activity). Results and conclusion: Excess iron decreased viability (21%, P < 0.01) of HIV-infected cells, increased p24 levels by 8.6% (P = 0.32) and elevated reverse transcriptase (RT) activity (81.7%, P < 0.01). The stimulation of viral replication was decreased when Fe was first complexed to desferrioxamine (DFO). DFO alone (in the absence of excess Fe), lowered cell viability (35%, P = 0.039) and in the presence of virus lowered both p24 levels (66%, P = 0.054) and RT activity (43%, P < 0.01) and unexpectedly increased cell viability (25%, P = 0.01047). Interleukin-2 (IL-2) production of infected cells was completely inhibited by DFO and excess iron while stress protein (Hsp70) levels were lowered in the presence of HIV in combination with excess iron (37%,P < 0.01)or DFO (47.2%, P < 0.01) when compared to untreated cells. According to flow cytometric data, HIV infection caused a two-fold increase in the numbers of necrotic (P = 0.006) and decreased apoptotic cells (28.5%, P = 0.15) cells. These findings indicate that Fe overload associated with HIV infection is detrimental to host cell responses against viral infection and that chelation can prevent and/or reverse this effect. (C) 2004 Elsevier B.V. All rights reserved.