Inhibition of CXCR4-tropic HIV-1 infection by lipopolysaccharide: Evidence of different mechanisms in macrophages and T lymphocytes

Alessia Verani, Francesca Sironi, Antonio G. Siccardi, Paolo Lusso, Donata Vercelli

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

Bacterial LPS protects primary human macrophages from infection by CCR5-tropic HIV-1 isolates through the release of the CC chemokines RANTES and macrophage inflammatory protein-1α and -1β. Here, we show that LPS also suppresses infection of macrophages by CXCR4-tropic HIV-1 isolates. A marked down-regulation of both CD4 and CXCR4 expression was associated with this effect. Furthermore, a soluble factor(s) released by macrophages upon LPS treatment inhibited infection with CXCR4-tropic HIV-1 isolate viruses in both macrophages and T lymphocytes. Infection of both cell types appeared to be blocked at the level of viral entry and was independent of stromal cell-derived factor-1, the only known natural ligand of CXCR4. Moreover, the suppressive effect of LPS was unrelated to the release of IFN-α and -β, macrophage-derived chemokine, leukemia inhibitory factor, or TNF-α. These results suggest the existence of potent HIV-1 inhibitory factor(s), uncharacterized to date, released by activated cells of the mononuclear phagocytic system.

Original languageEnglish (US)
Pages (from-to)6388-6395
Number of pages8
JournalJournal of Immunology
Volume168
Issue number12
DOIs
StatePublished - Jun 15 2002

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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