Innate inhibition of adaptive immunity: Mycobacterium tuberculosis-induced IL-6 inhibits macrophage responses to IFN-gamma.

Published

Journal Article

In humans and in mice, control of the intracellular pathogen, Mycobacterium tuberculosis (Mtb), requires IFN-gamma. Although the adaptive immune response results in production of substantial amounts of IFN-gamma in response to Mtb, the immune response is unable to eradicate the infection in most cases. We have previously reported evidence that Mtb inhibits macrophage responses to IFN-gamma, suggesting that this may limit the ability of IFN-gamma to stimulate macrophages to kill Mtb. We have also observed that uninfected macrophages, adjacent to infected macrophages in culture, exhibit decreased responses to IFN-gamma. Here we report that IL-6 secreted by Mtb-infected macrophages inhibits the responses of uninfected macrophages to IFN-gamma. IL-6 selectively inhibits a subset of IFN-gamma-responsive genes at the level of transcriptional activation without inhibiting activation or function of STAT1. Inhibition of macrophage responses to IFN-gamma by IL-6 requires new protein synthesis, but this effect is not attributable to suppressor of cytokine signaling 1 or 3. These results reveal a novel function for IL-6 and indicate that IL-6 secreted by Mtb-infected macrophages may contribute to the inability of the cellular immune response to eradicate infection.

Full Text

Duke Authors

Cited Authors

  • Nagabhushanam, V; Solache, A; Ting, L-M; Escaron, CJ; Zhang, JY; Ernst, JD

Published Date

  • November 1, 2003

Published In

Volume / Issue

  • 171 / 9

Start / End Page

  • 4750 - 4757

PubMed ID

  • 14568951

Pubmed Central ID

  • 14568951

International Standard Serial Number (ISSN)

  • 0022-1767

Digital Object Identifier (DOI)

  • 10.4049/jimmunol.171.9.4750

Language

  • eng

Conference Location

  • United States