HTLV-II down-regulates HIV-1 replication in IL-2-stimulated primary PBMC of coinfected individuals through expression of MIP-1α

The influence of human T-cell leukemia/ lymphoma virus type II (HTLV-II) in individuals also infected with HIV-1 is poorly understood, To evaluate the reciprocal influence of HTLV-II and HIV-1 infection, primary peripheral blood mononuclear cell (PBMC) cultures from coinfected individuals were established in the presence of interleukin 2 (IL-2), In these cultures, the kinetics of HTLV-II replication always preceded those of HIV-1. Noteworthy, the kinetics of HIV-1 production were inversely correlated to the HTLV-II proviral load in vi7vo and its replication ex vivo. These observations suggested a potential interaction between the 2 retroviruses, In this regard, the levels of IL-2, IL-6, and tumor necrosis factor-alpha (TNF-alpha) were measured in the same coinfected PBMC cultures. Endogenous IL-2 was not produced, whereas IL-6 and TNF-alpha were secreted at levels compatible with their known ability to up-regulate HIV-1 expression. The HIV-suppressive CC-chemokines RANTES, macrophage inflammatory protein-1 alpha (MIP-1 alpha), and MIP-1 beta were also determined in IL-2-stimulated PBMC cultures. Of interest, their kinetics and concentrations were inversely related to those of HIV-1 replication. Experiments were performed in which CD8(+) T cells or PBMCs from HTLV-II monoinfected individuals were cocultivated with CD4(+) T cells from HIV-1 monoinfected individuals separated by a semipermeable membrane in the presence or absence of antichemokine neutralizing antibodies. The results indicate that HTLV-II can interfere with the replicative potential of HIV-1 by upregulating viral suppressive CC-chemokines and, in particular, MIP-1 alpha. This study is the first report indicating that HTLV-II can influence HIV replication, at least in vitro, via up-regulation of HIV-suppressive chemokines, (Blood, 2000;95: 2760-2769) (C) 2000 by The American Society of Hematology.