Secreted immunodominant Mycobacterium tuberculosis antigens are processed by the cytosolic pathway

Jeff E. Grotzke, Anne C. Siler, Deborah Lewinsohn, David Lewinsohn

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Exposure to Mycobacterium tuberculosis can result in lifelong but asymptomatic infection in most individuals. Although CD8+ T cells are elicited at high frequencies over the course of infection in both humans and mice, how phagosomal M. tuberculosis Ags are processed and presented by MHC class I molecules is poorly understood. Broadly, both cytosolic and noncytosolic pathways have been described. We have previously characterized the presentation of three HLA-I epitopes from M. tuberculosis and shown that these Ags are processed in the cytosol, whereas others have demonstrated noncytosolic presentation of the 19-kDa lipoprotein as well as apoptotic bodies from M. tuberculosis-infected cells. In this paper, we now characterize the processing pathway in an additional six M. tuberculosis epitopes from four proteins in human dendritic cells. Addition of the endoplasmic reticulum-Golgi trafficking inhibitor, brefeldin A, resulted in complete abrogation of Ag processing consistent with cytosolic presentation. However, although addition of the proteasome inhibitor epoxomicin blocked the presentation of two epitopes, presentation of four epitopes was enhanced. To further examine the requirement for proteasomal processing of an epoxomicin-enhanced epitope, an in vitro proteasome digestion assay was established. We find that the proteasome does indeed generate the epitope and that epitope generation is enhanced in the presence of epoxomicin. To further confirm that both the epoxomicin-inhibited and epoxomicinenhanced epitopes are processed cytosolically, we demonstrate that TAP transport and new protein synthesis are required for presentation. Taken together, these data demonstrate that immunodominant M. tuberculosis CD8 + Ags are processed and presented using a cytosolic pathway. Copyright

Original languageEnglish (US)
Pages (from-to)4336-4343
Number of pages8
JournalJournal of Immunology
Volume185
Issue number7
DOIs
StatePublished - Oct 1 2010

Fingerprint

Epitopes
Mycobacterium tuberculosis
Proteasome Endopeptidase Complex
Brefeldin A
Asymptomatic Infections
Proteasome Inhibitors
Mycobacterium tuberculosis antigens
Endoplasmic Reticulum
Cytosol
Dendritic Cells
Lipoproteins
Digestion
Carrier Proteins
T-Lymphocytes
epoxomicin
Infection
Proteins

ASJC Scopus subject areas

  • Immunology
  • Medicine(all)

Cite this

Secreted immunodominant Mycobacterium tuberculosis antigens are processed by the cytosolic pathway. / Grotzke, Jeff E.; Siler, Anne C.; Lewinsohn, Deborah; Lewinsohn, David.

In: Journal of Immunology, Vol. 185, No. 7, 01.10.2010, p. 4336-4343.

Research output: Contribution to journalArticle

@article{8b7e4e1f8f984b8799ec82e125c263b7,
title = "Secreted immunodominant Mycobacterium tuberculosis antigens are processed by the cytosolic pathway",
abstract = "Exposure to Mycobacterium tuberculosis can result in lifelong but asymptomatic infection in most individuals. Although CD8+ T cells are elicited at high frequencies over the course of infection in both humans and mice, how phagosomal M. tuberculosis Ags are processed and presented by MHC class I molecules is poorly understood. Broadly, both cytosolic and noncytosolic pathways have been described. We have previously characterized the presentation of three HLA-I epitopes from M. tuberculosis and shown that these Ags are processed in the cytosol, whereas others have demonstrated noncytosolic presentation of the 19-kDa lipoprotein as well as apoptotic bodies from M. tuberculosis-infected cells. In this paper, we now characterize the processing pathway in an additional six M. tuberculosis epitopes from four proteins in human dendritic cells. Addition of the endoplasmic reticulum-Golgi trafficking inhibitor, brefeldin A, resulted in complete abrogation of Ag processing consistent with cytosolic presentation. However, although addition of the proteasome inhibitor epoxomicin blocked the presentation of two epitopes, presentation of four epitopes was enhanced. To further examine the requirement for proteasomal processing of an epoxomicin-enhanced epitope, an in vitro proteasome digestion assay was established. We find that the proteasome does indeed generate the epitope and that epitope generation is enhanced in the presence of epoxomicin. To further confirm that both the epoxomicin-inhibited and epoxomicinenhanced epitopes are processed cytosolically, we demonstrate that TAP transport and new protein synthesis are required for presentation. Taken together, these data demonstrate that immunodominant M. tuberculosis CD8 + Ags are processed and presented using a cytosolic pathway. Copyright",
author = "Grotzke, {Jeff E.} and Siler, {Anne C.} and Deborah Lewinsohn and David Lewinsohn",
year = "2010",
month = "10",
day = "1",
doi = "10.4049/jimmunol.1000801",
language = "English (US)",
volume = "185",
pages = "4336--4343",
journal = "Journal of Immunology",
issn = "0022-1767",
publisher = "American Association of Immunologists",
number = "7",

}

TY - JOUR

T1 - Secreted immunodominant Mycobacterium tuberculosis antigens are processed by the cytosolic pathway

AU - Grotzke, Jeff E.

AU - Siler, Anne C.

AU - Lewinsohn, Deborah

AU - Lewinsohn, David

PY - 2010/10/1

Y1 - 2010/10/1

N2 - Exposure to Mycobacterium tuberculosis can result in lifelong but asymptomatic infection in most individuals. Although CD8+ T cells are elicited at high frequencies over the course of infection in both humans and mice, how phagosomal M. tuberculosis Ags are processed and presented by MHC class I molecules is poorly understood. Broadly, both cytosolic and noncytosolic pathways have been described. We have previously characterized the presentation of three HLA-I epitopes from M. tuberculosis and shown that these Ags are processed in the cytosol, whereas others have demonstrated noncytosolic presentation of the 19-kDa lipoprotein as well as apoptotic bodies from M. tuberculosis-infected cells. In this paper, we now characterize the processing pathway in an additional six M. tuberculosis epitopes from four proteins in human dendritic cells. Addition of the endoplasmic reticulum-Golgi trafficking inhibitor, brefeldin A, resulted in complete abrogation of Ag processing consistent with cytosolic presentation. However, although addition of the proteasome inhibitor epoxomicin blocked the presentation of two epitopes, presentation of four epitopes was enhanced. To further examine the requirement for proteasomal processing of an epoxomicin-enhanced epitope, an in vitro proteasome digestion assay was established. We find that the proteasome does indeed generate the epitope and that epitope generation is enhanced in the presence of epoxomicin. To further confirm that both the epoxomicin-inhibited and epoxomicinenhanced epitopes are processed cytosolically, we demonstrate that TAP transport and new protein synthesis are required for presentation. Taken together, these data demonstrate that immunodominant M. tuberculosis CD8 + Ags are processed and presented using a cytosolic pathway. Copyright

AB - Exposure to Mycobacterium tuberculosis can result in lifelong but asymptomatic infection in most individuals. Although CD8+ T cells are elicited at high frequencies over the course of infection in both humans and mice, how phagosomal M. tuberculosis Ags are processed and presented by MHC class I molecules is poorly understood. Broadly, both cytosolic and noncytosolic pathways have been described. We have previously characterized the presentation of three HLA-I epitopes from M. tuberculosis and shown that these Ags are processed in the cytosol, whereas others have demonstrated noncytosolic presentation of the 19-kDa lipoprotein as well as apoptotic bodies from M. tuberculosis-infected cells. In this paper, we now characterize the processing pathway in an additional six M. tuberculosis epitopes from four proteins in human dendritic cells. Addition of the endoplasmic reticulum-Golgi trafficking inhibitor, brefeldin A, resulted in complete abrogation of Ag processing consistent with cytosolic presentation. However, although addition of the proteasome inhibitor epoxomicin blocked the presentation of two epitopes, presentation of four epitopes was enhanced. To further examine the requirement for proteasomal processing of an epoxomicin-enhanced epitope, an in vitro proteasome digestion assay was established. We find that the proteasome does indeed generate the epitope and that epitope generation is enhanced in the presence of epoxomicin. To further confirm that both the epoxomicin-inhibited and epoxomicinenhanced epitopes are processed cytosolically, we demonstrate that TAP transport and new protein synthesis are required for presentation. Taken together, these data demonstrate that immunodominant M. tuberculosis CD8 + Ags are processed and presented using a cytosolic pathway. Copyright

UR - http://www.scopus.com/inward/record.url?scp=77958123389&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77958123389&partnerID=8YFLogxK

U2 - 10.4049/jimmunol.1000801

DO - 10.4049/jimmunol.1000801

M3 - Article

C2 - 20802151

AN - SCOPUS:77958123389

VL - 185

SP - 4336

EP - 4343

JO - Journal of Immunology

JF - Journal of Immunology

SN - 0022-1767

IS - 7

ER -