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Infection and Immunity, August 2002, p. 4019-4027, Vol. 70, No. 8
0019-9567/02/$04.00+0 DOI: 10.1128/IAI.70.8.4019-4027.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.
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2+ T Cells: Modulation by Chloroquine
Department of Medicine, Case Western Reserve University and University Hospitals of Cleveland,1 Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106,3 INSERM U395, CHU Purpan, 31024 Toulouse, France2
Received 14 January 2002/ Returned for modification 25 February 2002/ Accepted 1 May 2002
V
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2+ T cells (
T cells) are activated by Mycobacterium tuberculosis and recognize mycobacterial nonpeptide phosphoantigens. The role of antigen-presenting cells in the processing and presentation of phosphoantigens to V
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2+ T cells is not understood. We analyzed the role of macrophages for activation of 
T cells by a new synthetic phosphoantigen bromohydrin pyrophosphate (BrHPP) and M. tuberculosis. Macrophages greatly increased 
T-cell activation by both BrHPP and M. tuberculosis. Fixation of macrophages before infection demonstrated that uptake of M. tuberculosis was required for presentation to 
T cells. Antigens of M. tuberculosis remained stably associated with macrophage surface and were not removed by paraformaldehyde fixation or washing. Macrophages processed M. tuberculosis for 
T cells through a brefeldin A-insensitive pathway, suggesting that transport through the endoplasmic reticulum and Golgi complex of a putative presenting molecule is not important in the early processing of M. tuberculosis antigens for 
T cells. Processing of M. tuberculosis was not eliminated by chloroquine, indicating that processing of 
antigens is not dependent on acidic pH in the lysosomes. Chloroquine treatment of BrHPP-pulsed macrophages increased activation of 
T cells. Ammonium chloride treatment of macrophages did not increase reactivity of 
T cells to BrHPP, indicating that the effect of chloroquine was independent of pH changes in endosomes. Chloroquine, by inhibiting membrane traffic, may increase association and retention of phosphoantigens with cell surface membrane molecules on macrophages.
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