INTERLEUKIN-13 INHIBITS HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 PRODUCTION IN PRIMARY BLOOD-DERIVED HUMAN MACROPHAGES IN-VITRO

The mechanisms by which cellular immunity maintains the asymptomatic s tate after human immunodeficiency virus type 1 (HIV-1) infection are p oorly understood. CD4+ T lymphocytes play a complex role in regulating anti-HIV effector pathways, including activation of macrophages, whic h are themselves implicated in clinical latency and pathogenesis of sy mptomatic acquired immune deficiency syndrome. We have found that a ne wly identified T helper type 2 lymphokine, interleukin 13 (IL-13), inh ibits HIV-1ADA 2nd Ba-L replication in primary tissue culture-derived macrophages but not in peripheral blood lymphocytes. Viral production in cells was measured by viral protein (p24) and reverse transcriptase levels, while entry was assessed by proviral DNA analysis at timed in tervals after infection. Inhibition by IL-13 was dose and time depende nt and not mediated through altered viral entry, reverse transcription , or viral release. IL-13 is therefore a candidate cytokine for the su ppression of HIV infection within monocytes and macrophages in vivo.