Dendritic cells infected with Mycobacterium bovis bacillus Calmette Guerin activate CD8+ T cells with specificity for a novel mycobacterial epitope
Carl G. Feng1,
Caroline Demangel1,2,
Arun T. Kamath1,
Murdo Macdonald1 and
Warwick J. Britton1,3
1 Centenary Institute of Cancer Medicine and Cell Biology, Locked Bag No. 6, Newtown, NSW 2042, Australia
2 Institut Pasteur, Laboratoire d'Ingenierie des Anticorps, 28 Rue du Dr Roux, 75724 Paris Cedex 15, France
3 Department of Medicine, University of Sydney, Sydney, NSW 2006 Australia
Correspondence to:
W. J. Britton, Centenary Institute of Cancer Medicine and Cell Biology, Locked Bag No. 6, Newtown, NSW, 2042 Australia
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Abstract
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Although CD4+ T cells are essential for protective immunity against Mycobacterium tuberculosis infection, recent reports indicate that CD8+ T cells may also play a critical role in the control of this infection. However, the epitope specificity and the mechanisms of activation of mycobacteria-reactive CD8+ T cells are poorly characterized. In order to study the CD8+ T cell responses to the model mycobacterial antigen, MPT64, we used recombinant vaccinia virus expressing MPT64 (VVWR-64) and a panel of MPT64-derived peptides to establish that the peptide MPT64190198 contains an H-2Db-restricted CD8+ T cell epitope. A cytotoxic T lymphocyte response to this peptide could be demonstrated in M. bovis bacillus Calmette Guerin (BCG)-infected mice following repeated in vitro stimulation. When bone marrow-derived dendritic cells (DC) were infected with BCG, the expression of MHC class I molecules by DC was up-regulated in parallel with MHC class II and B7-2, whereas CD1d expression level was not modified. Moreover, BCG-infected DC activated MPT64190198-specific CD8+ T cells to secrete IFN-
, although with a lower efficacy than VVWR-64-infected DC. The production of IFN-
by MPT64190198-specific CD8+ T cells was inhibited by antibodies to MHC class I, but not to CD1d. These data suggest that mycobacteria-specific CD8+ T cells are primed during infection. Therefore, anti-mycobacterial vaccine strategies targeting the activation of specific CD8+ T cells by DC may have improved protective efficacy.
Keywords: CD8+ T cells, dendritic cell, epitope, mycobacteria, vaccinia virus
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Introduction
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Tuberculosis (TB) is a major public health problem, and its incidence is increasing due to the HIV/AIDS pandemic and the emergence of multidrug-resistant strains of Mycobacterium tuberculosis. Several lines of evidence have demonstrated that protective immunity against infection with M. tuberculosis and M. bovis bacillus Calmette-Guerin (BCG) is essentially mediated by MHC class II-restricted CD4+ T cells (1,2). This cell subset represents a major source of cytokines activating macrophage bactericidal effector functions such as IFN-
, therefore contributing to the containment of infection (3,4). Recently, it has been reported that CD8+ T cells of Th1 phenotype accumulate during the early phase of M. tuberculosis infection in the lungs of infected mice (5,6). As mice deficient in CD8+ T cells are unable to adequately control tuberculosis infection (7), these data suggest that CD8+ T cells may play an important role in the generation of protective immunity against M. tuberculosis infection.
Presently little is known concerning the mechanisms of induction and the specificity of CD8+ T cells during mycobacterial infections. In contrast to viruses which replicate in the cytosol of infected cells, M. tuberculosis appears to remain in the endosomal compartment. The presentation of mycobacterial peptides to CD8+ T cells has been reported in association with MHC class I (8,9), CD1 (10,11) and non-classical MHC class Ib molecules (12), but the mechanisms by which mycobacterial antigens escape the phagosome and enter these presentation pathways are still unclear. The antigen specificity of mycobacteria-reactive CD8+ T cells in M. tuberculosis-infected humans (8) and mice (9) is also poorly understood. Although the presence of epitope-specific CD8+ T cells was clearly demonstrated in mice immunized with mycobacterial antigen-expressing plasmid DNA, CD8+ T cells with specificity for the same epitopes were not detected in BCG- or M. tuberculosis-infected mice (13,14). These observations suggest that the presentation of mycobacterial antigens to CD8+ T cells is relatively inefficient, possibly because of the low level of endogenous expression of antigens in infected antigen-presenting cells (APC). Therefore, the study of CD8+ T cells responses to mycobacterial antigens may be facilitated by the use of viral expression vectors.
In the present work, we have characterized the CD8+ T cells response induced by a model mycobacterial antigen when expressed by a recombinant vaccinia virus (VV). The proteins secreted by mycobacteria in short-term culture filtrate are major antigens leading to protective immunity against M. tuberculosis via the activation of both CD4+ and CD8+ T cells (15,16). One of these secreted antigens, MPT64, was selected as it is commonly recognized by TB patients and their contacts (17), and elicits a strong delayed-type hypersensitivity response in guinea pigs (18). Immunization of mice with VV expressing MPT64 (VVWR-64) allowed us to identify a novel H-2Db-restricted peptide contained within MPT64 (MPT64190198). We found that a cytotoxic T lymphocyte (CTL) response specific to MPT64190198 was generated in mice following infection with BCG, although to a lower extent than with VVWR-64. Importantly, dendritic cells (DC) infected with BCG in vitro activated MPT64190198-specific CD8+ T cells in a MHC class I-restricted context. These results provide evidence that MPT64190198 is presented to CD8+ T cells during mycobacterial infections, but suggest that MPT64190198-specific CD8+ T cell clones are generated in vivo at low frequencies.
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Methods
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Mice
C57BL/6 female mice were supplied by Animal Resources Centre (Perth, Australia) and maintained as previously described (5).
Bacteria and synthetic peptides
BCG (Tokyo strain), which expresses and secretes MPT64 protein (19), was obtained from ATCC (Rockville, MD). The predicted MPT64 peptides and control peptides were purchased from Research Genetics (Huntsville, AL). Sequence predictions were based on a scheme developed by Dr K. Parker (20).
Construction of recombinant VV
The VVWR-64 was constructed by cloning the mpt64 gene into the vaccinia shuttle plasmid pBCB06 for homologous recombination into the thymidine kinase (TK) locus of the Western Reserve strain of VV. Recombinant VVWR were selected with 5-bromodeoxyuridine in a TK cell line, 143B. The recombinant VVWR was screened with DNA dot-blots and immunofluorescence. Following three rounds of plaque purifications, recombinant VV was expanded and viral stocks were prepared by ultracentrifugation through a sucrose cushion. The pBCB06 plasmid and a control VVWR expressing hemagglutinin of influenza virus (VVWR-PR8/HA6) were provided by Dr D. Boyle (CSIRO, Geelong, Australia).
Western blot analysis
Virus-infected 143B cell lysates were separated by SDSPAGE (15% gel). The proteins were then transferred to a nitrocellulose membrane and detected with an anti-MPT64 rabbit serum followed by a horseradish peroxidase-conjugated donkey anti-rabbit IgG (Amersham, Little Chalfont, UK). The reaction was developed using an enhanced chemiluminescence reagent (Pierce, Rockford, IL). For inhibition experiments, TK 143B cells were infected with VVWR-64 in the presence of tunicamycin (1 µg/ml) (Sigma, St Louis, MO) for 24 h.
In vitro stimulation of effectors and generation of CD8+ T cell lines
Mice were infected i.v. with 107 p.f.u. of recombinant VV or 5x106 c.f.u. of BCG. Between 6 and 8 weeks later, splenocytes (5x106/ml) from infected mice were re-stimulated with peptides (5 µM) in complete RPMI (RPMI supplemented with 10% FBS, 2 mM L-glutamine, 10 mM HEPES, 0.5 µM 2-mercaptoethanol, 100 U/ml penicillin and 100 µg/ml streptomycin) in 24-well plates. Recombinant murine IL-2 (10 U/ml) (Boehringer Mannheim, Mannheim, Germany) was added 24 h later. To maintain MPT64 peptide-specific CD8+ T cell lines, 5x104/well T cells were re-stimulated weekly with 5x106/well irradiated syngeneic splenocytes and 5 µM peptide in the presence of IL-2.
51Cr-release assay
EL-4 (H-2b) target cells were pulsed with peptides (20 µM) and labeled with 100 µCi 51Cr (NEN Life Sciences, Boston, MA) for 1.5 h at 37°C. Labeled target cells were then incubated with effector cells at various ratios (E:T) for 4 h. The radioactivity released in culture supernatants was measured with a
-counter (Packard, ACT, Australia). The total release was determined by Triton X-100 lysis of labeled target cells. The percentage of specific lysis was calculated as follows:
. Spontaneous release was always <20% of the total release. For blocking experiments, mAb were added to the target cells 30 min before incubating with effector cells.
mAb, FACS staining and flow cytometry analysis
The following mAb were used for flow cytometry analysis or in inhibition experiments: culture supernatant of mAb specific for CD86 (B7.2) (clone GL1), I-A (clone Y3P), H-2Kb (clone K9-178) and H-2Db (clone B22.249) were provided by Dr P. Bertolino (Centenary Institute). FITC-conjugated anti-IFN-
(clone AN18), anti-CD1d (clone 1B1, PharMingen, San Diego, CA) and goat anti-rat IgG (Caltag, San Francisco, CA). Phycoerythrin (PE)-conjugated anti-CD4 (clone RM4-4; PharMingen), anti-IL4 (clone 11B11) and anti-CD11C (HL3). TriColor-conjugated anti-CD8
(clone CT-CD8a) and isotype control mAb were obtained from Caltag. Procedures for staining and flow cytometry analysis have been previously described (5). For detection of intracellular cytokines, CD8+ T cells specific for MPT64190198 were cultured with EL4 pulsed with either MPT64190198 or a control peptide for 4 h at 37°C in the presence of Brefeldin A (10 µg/ml) (Sigma). Unpulsed EL4 cells were included as control cells. The intracellular expression of cytokines in CD8+ T cells was then detected by flow cytometry.
Co-culture of infected bone marrow-derived DC with CD8+ T cell lines
Bone marrow-derived DC were generated and infected with BCG as previously described (21). For infection with VVWR-64, DC were infected with the virus at a m.o.i. of 10:1 for 1 h at 37°C. After washing, infected DC were incubated 16 h at 37°C before assay. Eleven days after re-stimulation, 105 MPT64190198-specific CD8+ T cells were cultured with 105 DC infected with BCG or VVWR-64. MPT64190198 peptide-pulsed or untreated DC were included as controls. Production of IFN-
in culture supernatants after 48 h was analyzed by ELISA. For inhibition assays, culture supernatants from hybridomas producing mAb specific for I-A, H-2Db or purified anti-CD1d mAb (5 µg/ml) were added to DC cultures at the time of incubation with MPT64190198-specific CD8+ T cells.
IFN-
ELISPOT
Splenocytes isolated from mice infected with BCG or VVWR-64 were stained with a FITC-conjugated anti-CD8 mAb (clone 53-6.7; PharMingen) for 10 min at 4°C. FITC-stained cells were then positively selected using anti-FITC microbeads (Miltenyi Biotec, Bergish Gladbach, Germany) and a Midi-MACS separation column (Miltenyi Biotec) according to the manufacturer's instructions. For the ELISPOT assays, 96-well nitrocellulose plates (Millipore, Bedford, MA) were coated with AN18 mAb overnight at 4°C. After blocking, serial dilutions of purified CD8+ T cells were added to irradiated syngeneic splenocytes (5x105/well) with or without peptides (5 µM) for 18 h at 37°C. The plates were then washed with PBS and incubated with biotinylated XMG1.2 mAb for 2 h at room temperature. The color was developed using avidinalkaline phosphatase (Sigma) and specific substrate kit (BioRad, Hercules, CA).
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Results
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Construction of VVWR-64
In order to generate high levels of endogenous expression of MPT64 and to enhance the protein delivery to the MHC class I presentation pathway, a recombinant VV expressing MPT64 was constructed. Western blot analysis performed on lysates of TK 143B cells infected with the recombinant viruses confirmed that a 23 kDa mycobacterial protein corresponding to the native MPT64 from BCG was expressed (Fig. 1A
). In addition, a protein of higher mol. wt was also detected. When TK 143B cells were infected with VVWR-64 in the presence of tunicamycin, an inhibitor of N-linked glycosylation, the formation of this band was inhibited, demonstrating that VVWR-64 infected cells expressed both glycosylated and non-glycosylated forms of MPT64.

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Fig. 1. Infection of mice with VVWR-64 induces a cytotoxic response to a MPT64-derived peptide, MPT64190198. (A) MPT64 expression by VVWR-64-infected cells in the presence or absence of tunicamycin, as shown by Western blot analysis. VVWR-PR8/HA6-infected cell lysates were used as a negative control and BCG culture filtrate was used as a source for native MPT64. (B) Cytolytic activity of splenocytes from VVWR-64-infected mice to MPT64-derived peptides. Cytotoxicity was assessed on peptide-pulsed target at an E:T ratio of 100:1. No peptide-specific lysis was detected in unimmunized or in VVWR-PR8/HA6-infected mice (data not shown).
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Infection of mice with VVWR-64 induces cytotoxic and IFN-
responses to a MPT64-derived peptide, MPT64190198
The ability of VVWR-64 to induce a CTL response to MPT64 was tested using a panel of 9mer MPT64 peptides with sequences predicted to bind to H-2Kb or Db alleles (Table 1
). Splenocytes from mice infected with VVWR-64 were re-stimulated in vitro with the selected peptides for 6 days. The cytolytic activity was then tested in a standard 51Cr-release assay, using peptide-pulsed EL4 cells as targets. Figure 1
(B) shows that splenocytes from VVWR-64-infected mice showed reactivity to one of the peptides, MPT64190198.
The effector functions and phenotype of MPT64190198-specific CTL were characterized after three or four rounds of weekly stimulation. These CTL efficiently lysed MPT64190198 peptide-pulsed EL4 cells (Fig. 2A
) and rapidly produced IFN-
, but no IL-4, following re-exposure to the peptide (Fig. 2B
). These effects were specific to the MPT64190198 peptide, since no cytolytic activity or cytokine production were observed following re-stimulation with EL4 cells alone, or with EL4 pulsed with a control peptide (data not shown). Flow cytometry analysis confirmed that the MPT64190198-specific CTL were of the CD8+ phenotype (Fig. 2C
). The specific lysis of EL4 cells pulsed with MPT64190198 was inhibited by an anti-Db mAb (Fig. 2D
). Therefore, the cytolytic and IFN-
-producing CD8+ T cell line recognized MPT64190198 peptide in association with H-2Db.
MPT64190198-specific CTL can be detected in BCG-infected mice following repeated stimulation
To investigate whether MPT64-specific CTL were generated in vivo following BCG infection, splenocytes from BCG-infected mice were stimulated with the same panel of MPT64 peptides and their cytotoxic activity to peptide-pulsed target cells was tested. No cytolytic activity could be demonstrated with any of the MPT64 peptides after 6 days of in vitro stimulation (Fig. 3A
). In order to increase the sensitivity of detection of MPT64-specific CD8+ T cells, an IFN-
ELISPOT assay was performed with CD8+ T cells purified by the MACS separation system. By this method, CD8+ T cell preparation purity was >93% (data not shown). In accordance with the cytotoxicity assays, a potent IFN-
response was observed with CD8+ T cells isolated from spleens of VVWR-64-infected mice, but not from BCG-infected animals (Fig. 3B
). CD8+ T cell reactivity to peptide P38225234, another H-2Db-restricted CD8+ T cell epitope contained in the 38 kDa mycobacterial protein (14), was also tested. The production of IFN-
by CD8+ T cells from BCG-infected mice in response to P38225234 was also not detected.
To determine whether this lack of response was due to the low frequency of MPT64-reactive CTL in BCG-infected animals, splenocytes from BCG-infected mice were repeatedly stimulated with the peptides in vitro before cytolytic activity was assessed. After 4 weeks of stimulation, cytotoxic activity to the MPT64190198 peptide was detected (Fig. 4
). No activity was observed with the other four peptides.

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Fig. 4. MPT64190198-specific CTL can be detected in BCG-infected mice following repeated stimulation in vitro. The cytotoxic activity of splenocytes from BCG-immunized animals on MPT64190198 peptide-pulsed (solid squares) or unpulsed (open squares) target cells is shown after four weekly re-stimulations in vitro.
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MPT64190198-specific CD8+ T cells recognize BCG-infected DC
The previous results suggest that MPT64190198-specific CD8+ T cells were primed during BCG infection, but with a lower efficacy than during infection with VVWR-64. Since DC are major APC for the induction of T cell responses, we next examined the ability of DC to present MPT64190198 to CD8+ T cells in vitro following BCG or VVWR-64 infection. Figure 5
compares the IFN-
production levels in co-cultures of the MPT64190198-specific CD8+ T cell line and of BCG-infected, VVWR-64-infected or MPT64190198-pulsed DC. BCG-infected DC activated CD8+ T cells to produce IFN-
, demonstrating that MPT64190198 is processed by DC following BCG infection. However, T cell activation with BCG-infected DC, as measured by IFN-
production, was less potent than with VVWR-64-infected DC or peptide-pulsed DC.
MPT64190198 presentation by BCG-infected DC is MHC class I restricted
BCG infection of DC is known to induce cell maturation (21), as shown by the up-regulation of MHC class II and co-stimulatory B7-2 molecules (Fig. 6A
). In order to elucidate the pathway of MPT64190198 presentation, expression of MHC class I and CD1d molecules on BCG-infected DC was analyzed by flow cytometry (Fig. 6A
). BCG-induced maturation of DC was associated with the up-regulation of MHC class I molecules, whereas the expression of CD1d was not modified. When BCG-infected DC were incubated with a mAb blocking H-2Db molecule and co-cultured with a MPT64190198-specific CD8+ T cell line, IFN-
production was inhibited (Fig. 6B
). In contrast, anti-I-A and anti-CD1d blocking mAb did not modify DC-mediated T cell activation, demonstrating that MPT64190198 presentation on BCG-infected DC is MHC class I-restricted.
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Discussion
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CD8+ T cells appear to play a role in the control of both human and murine TB (22,23). Although mycobacteria-reactive CD8+ T cells can be detected in BCG-infected mice, BCG-vaccinated individuals and TB patients (8,24,25), only few CD8+ T cell epitopes have been identified to date (14,26,27). In the present study, we have defined a novel H-2Db-restricted epitope within MPT64, a major mycobacterial antigen secreted by BCG and M. tuberculosis. The observations that CD8+ CTL recognizing MPT64190198 are generated in BCG-infected mice and that BCG-infected DC activate the MPT64190198-specific CD8+ T cell line strongly suggest that this epitope is processed and presented by host APC during mycobacterial infections. As for other reported mycobacterial epitopes, the presence of cytolytic CD8+ T cells specific to MPT64190198 could not be demonstrated directly ex vivo and required repeated in vitro stimulation (2628), suggesting that mycobacteria-specific CD8+ CTL are primed during infection at a very low frequency. This raises the question of how CD8+ T cell responses of such low amplitude can participate in protective immunity against M. tuberculosis infection. The possibility remains that mycobacteria-specific CD8+ T cells with a phenotype other than cytolytic or IFN-
producing are also generated. Indeed, it has been shown that the number of IL-4-producing CD8+ T cells increased in the peripheral blood of patients with cavitary TB (29). Moreover, CD8+ T cells may exert a protective role against mycobacterial infections by regulating the effector functions of CD4+ T cells (30,31).
It is still unclear how mycobacteria that reside primarily within phagosomes of infected macrophages can elicit a CD8+ T cell response. Indeed, the classical MHC class I presentation pathway actively transports peptides generated by degradation of endogenous proteins from the cytosol to the endoplasmic reticulum where they bind to MHC class I molecules. Alternatively, exogenous antigens which do not access to the cytosol can be presented in MHC class I context via a non-classical pathway (32,33). M. tuberculosis infection facilitates the presentation of soluble antigen to CD8+ T cells (34). Moreover, the presentation of mycobacterial peptides to CD8+ T cells is not modified by cell treatment with Brefeldin A, an inhibitor of transport through the Golgi apparatus (8,24). Taken together, these data suggest that the alternative MHC class I presentation pathway may operate within mycobacteria-infected APC.
The numbers of MPT64-specific CTL and IFN-
-secreting CD8+ T cells was significantly lower in BCG-infected than in VVWR-64-infected mice. Similar discrepancies in the frequency of mycobacterial antigen-specific CD8+ T cells were observed when comparing DNA-vaccinated to mycobacteria-infected animals (13,14). BCG-infected DC were less efficient at presenting the MPT64190198 peptide to specific CD8+ T cells than VVWR-64-infected DC. Therefore, the low frequency of reactive CD8+ T cells generated during mycobacterial infections may be related to the capacity of mycobacteria-infected DC to present antigens via the MHC class I presentation pathway. Several reasons may account for this. First, the subcellular location of mycobacteria favors the processing of antigens via the MHC class II presentation pathway and the subsequent activation of CD4+ T cells. Second, there is evidence demonstrating that antigen presentation to CD8+ T cells via the non-classical exogenous pathway is less efficient than the endogenous pathway (8,24) and requires higher concentrations of soluble antigens (32,33). As a result of this inefficient antigen presentation, the selection and the expansion of CD8+ T cell clones specific for dominant epitopes, as observed during viral and Listeria infections, may not occur during mycobacterial infections. Instead, the CD8+ T cell response to mycobacterial antigens may consist of a broad repertoire of rare CD8+ T cell clones.
DC are major APC for the generation of primary T cell responses against microbial infections (35). Infection of DC with BCG or M. tuberculosis leads to direct cell activation, with up-regulated expression of T cell co-stimulatory and MHC class II molecules (21,36). Infected DC therefore have an increased ability to prime naive CD4+ T cells against internalized antigens. The expression of MHC class I molecules is also augmented following BCG or M. tuberculosis infection (Fig. 6
) (21,36), suggesting that DC also play a role in the priming of CD8+ T cells against microbial antigens. DC are able to prime naive CD8+ T cells in vitro when pulsed with mycobacterial peptides. Our finding that the MPT64190198 peptide is presented by DC following infection with BCG and that MPT64190198 presentation results in the activation of specific CD8+ T cells, further supports the evidence that DC are critical APC for the generation of specific CD8+ T cell responses against mycobacterial antigens.
CD8+ T cells reacting to mycobacterial antigens presented by CD1 molecules of group I (CD1a, b and c) are able to lyse M. tuberculosis-infected macrophages and therefore contribute to the control of mycobacterial infection in human (10). Group II CD1 molecules in human, which are homologous to the murine CD1d, have been less extensively studied and there is no evidence to date that they also present mycobacterial antigens. The recognition of M. tuberculosis-infected macrophages by CTL is MHC class I restricted in mice (9). As CD1d-deficient mice show equivalent susceptibility to M. tuberculosis infection as wild-type animals (7,37), it appears that the presentation of mycobacterial antigens by CD1d molecules may not play an important role in protective immunity against tuberculosis in mice. This conclusion is supported by the fact that MPT64190198 peptide presentation by DC to CD8+ T cells was associated with MHC class I molecules and not with CD1d. This is also consistent with the finding that BCG infection significantly enhanced the expression of MHC class I and II molecules but not CD1d on DC.
Given the worldwide spread of TB, it is crucial to develop more effective vaccines than M. bovis BCG, which remains the only available vaccine at present. Our data provide further evidence that BCG is a poor inducer of anti-mycobacterial CD8+ T cell responses. As CD8+ T cells play a critical role in the control of both murine and human TB (7,22,23), vaccination strategies promoting the development of mycobacteria-reactive CD8+ T cells may have improved protective efficacy. When compared to BCG, recombinant VV expressing MPT64 generated CTL responses specific for MPT64 with a far greater efficiency. This result shows that VV represent a useful tool for the identification of CD8+ epitopes on defined mycobacterial proteins, as well as carriers of mycobacterial antigens for the induction of anti-mycobacterial CD8+ T cell responses. Alternatively, vaccination strategies promoting the development of anti-mycobacterial CD8+ T cell responses by DC may have increased protective efficacy.
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Acknowledgments
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This work was supported by the National Health and Medical Research Council of Australia and the Immunology of Mycobacteria (IMMYC) Program of the WHO. C. G. F. and A. T. K. are recipients of Australian Postgraduate Awards. The support of the NSW Health Department through its research and development infrastructure grants programme is gratefully acknowledged. We thank Dr A. Bean for helpful discussions.
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Abbreviations
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APC antigen-presenting cells |
BCG Mycobacterium bovis bacillus Calmette-Guerin |
CTL cytotoxic T lymphocyte |
DC dendritic cells |
TB tuberculosis |
TK thymidine kinase |
VV vaccinia virus |
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Notes
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Transmitting editor: A. Kelso
Received 28 March 2000,
accepted 18 December 2000.
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References
|
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-
Caruso, A. M., Serbina, N., Klein, E., Triebold, K., Bloom, B. R. and Flynn, J. L. 1999. Mice deficient in CD4+ T cells have only transiently diminished levels of IFN-
, yet succumb to tuberculosis. J. Immunol. 162:5407.[Abstract/Free Full Text]
-
Ladel, C. H., Daugelat, S. and Kaufmann, S. H. 1995. Immune response to Mycobacterium bovis bacille Calmette Guerin infection in major histocompatibility complex class I- and II-deficient knock-out mice: contribution of CD4+ and CD8+ T cells to acquired resistance. Eur. J. Immunol. 25:377.[ISI][Medline]
-
Cooper, A. M. and Flynn, J. L. 1995. The protective immune response to Mycobacterium tuberculosis. Curr. Opin. Immunol. 7:512.[ISI][Medline]
-
Andersen, P. 1997. Host responses and antigens involved in protective immunity to Mycobacterium tuberculosis. Scand. J. Immunol. 45:115.[ISI][Medline]
-
Feng, C. G., Bean, A. G., Hooi, H., Briscoe, H. and Britton, W. J. 1999. Increase in IFN
-secreting CD8+, as well as CD4+, T cells in lungs following aerosol infection with Mycobacterium tuberculosis. Infect. Immun. 67:3242.[Abstract/Free Full Text]
-
Serbina, N. V. and Flynn, J. L. 1999. Early emergence of CD8+ T cells primed for production of type 1 cytokines in the lungs of Mycobacterium tuberculosis-infected mice. Infect. Immun. 67:3980.[Abstract/Free Full Text]
-
Sousa, A. O., Mazzaccaro, R. J., Russell, R. G., Lee, F. K., Turner, O. C., Hong, S., Van Kaer, L. and Bloom, B. R. 2000. Relative contributions of distinct MHC class I-dependent cell populations in protection to tuberculosis infection in mice. Proc. Natl Acad. Sci. USA 97:4204.[Abstract/Free Full Text]
-
Canaday, D. H., Ziebold, C., Noss, E. H., Chervenak, K. A., Harding, C. V. and Boom, W. H. 1999. Activation of human CD8+
ßTCR+ cells by Mycobacterium tuberculosis via an alternate class I MHC antigen-processing pathway. J. Immunol. 162:372.[Abstract/Free Full Text]
-
Serbina, N. V., Liu, C. C., Scanga, C. A. and Flynn, J. L. 2000. CD8+ CTL from lungs of Mycobacterium tuberculosis-infected mice express perforin in vivo and lyse infected macrophages. J. Immunol. 165:353.[Abstract/Free Full Text]
-
Stenger, S., Mazzaccaro, R. J., Uyemura, K., Cho, S., Barnes, P. F., Rosat, J. P., Sette, A., Brenner, M. B., Porcelli, S. A., Bloom, B. R. and Modlin, R. L. 1997. Differential effects of cytolytic T cell subsets on intracellular infection. Science 276:1684.[Abstract/Free Full Text]
-
Rosat, J. P., Grant, E. P., Beckman, E. M., Dascher, C. C., Sieling, P. A., Frederique, D., Modlin, R. L., Porcelli, S. A., Furlong, S. T. and Brenner, M. B. 1999. CD1-restricted microbial lipid antigen-specific recognition found in the CD8+
ß T cell pool. J. Immunol. 162:366.[Abstract/Free Full Text]
-
Lewinsohn, D. M., Alderson, M. R., Briden, A. L., Riddell, S. R., Reed, S. G. and Grabstein, K. H. 1998. Characterization of human CD8+ T cells reactive with Mycobacterium tuberculosis-infected antigen-presenting cells. J. Exp. Med. 187:1633.[Abstract/Free Full Text]
-
Denis, O., Tanghe, A., Palfliet, K., Jurion, F., van den Berg, T. P., Vanonckelen, A., Ooms, J., Saman, E., Ulmer, J. B., Content, J. and Huygen, K. 1998. Vaccination with plasmid DNA encoding mycobacterial antigen 85A stimulates a CD4+ and CD8+ T-cell epitopic repertoire broader than that stimulated by Mycobacterium tuberculosis H37Rv infection. Infect. Immun. 66:1527.[Abstract/Free Full Text]
-
Zhu, X., Stauss, H. J., Ivanyi, J. and Vordermeier, H. M. 1997. Specificity of CD8+ T cells from subunit-vaccinated and infected H-2b mice recognizing the 38 kDa antigen of Mycobacterium tuberculosis. Int. Immunol. 9:1669.[Abstract]
-
Boesen, H., Jensen, B. N., Wilcke, T. and Andersen, P. 1995. Human T-cell responses to secreted antigen fractions of Mycobacterium tuberculosis. Infect. Immun. 63:1491.[Abstract]
-
Denis, O., Lozes, E. and Huygen, K. 1997. Induction of cytotoxic T-cell responses against culture filtrate antigens in Mycobacterium bovis bacillus Calmette-Guerin-infected mice. Infect. Immun. 65:676.[Abstract]
-
Roche, P. W., Triccas, J. A., Avery, D. T., Fifis, T., Billman-Jacobe, H. and Britton, W. J. 1994. Differential T cell responses to mycobacteria-secreted proteins distinguish vaccination with bacille Calmette-Guerin from infection with Mycobacterium tuberculosis. J. Infect. Dis. 170:1326.[ISI][Medline]
-
Oettinger, T., Holm, A., Mtoni, I. M., Andersen, A. B. and Haslor, K. 1995. Mapping of the delayed-type hypersensitivity-inducing epitope of secreted protein MPT64 from Mycobacterium tuberculosis. Infect. Immun. 63:4613.[Abstract]
-
Yamaguchi, R., Matsuo, K., Yamazaki, A., Abe, C., Nagai, S., Terasaka, K. and Yamada, T. 1989. Cloning and characterization of the gene for immunogenic protein MPB64 of Mycobacterium bovis BCG. Infect. Immun. 57:283.[ISI][Medline]
-
Parker, K. C., Bednarek, M. A. and Coligan, J. E. 1994. Scheme for ranking potential HLA-A2 binding peptides based on independent binding of individual peptide side-chains. J. Immunol. 152:163.[Abstract/Free Full Text]
-
Demangel, C., Bean, A. G., Martin, E., Feng, C. G., Kamath, A. T. and Britton, W. J. 1999. Protection against aerosol Mycobacterium tuberculosis infection using Mycobacterium bovis Bacillus Calmette Guerin-infected dendritic cells. Eur. J. Immunol. 29:1972.[ISI][Medline]
-
Flynn, J. L., Goldstein, M. M., Triebold, K. J., Koller, B. and Bloom, B. R. 1992. Major histocompatibility complex class I-restricted T cells are required for resistance to Mycobacterium tuberculosis infection. Proc. Natl Acad. Sci. USA 89:12013.[Abstract]
-
Bothamley, G. H., Festenstein, F. and Newland, A. 1992. Protective role for CD8+ cells in tuberculosis. Lancet 339:315.[ISI][Medline]
-
Denis, O. and Huygen, K. 1999. Characterization of the culture filtrate-specific cytotoxic T lymphocyte response induced by bacillus Calmette-Guerin vaccination in H-2b mice. Int. Immunol. 11:209.[Abstract/Free Full Text]
-
Smith, S. M., Malin, A. S., Lukey, P. T., Atkinson, S. E., Content, J., Huygen, K. and Dockrell, H. M. 1999. Characterization of human Mycobacterium bovis bacille Calmette-Guerin-reactive CD8+ T cells. Infect. Immun. 67:5223.[Abstract/Free Full Text]
-
Lalvani, A., Brookes, R., Wilkinson, R. J., Malin, A. S., Pathan, A. A., Andersen, P., Dockrell, H., Pasvol, G. and Hill, A. V. 1998. Human cytolytic and IFN
-secreting CD8+ T lymphocytes specific for Mycobacterium tuberculosis. Proc. Natl Acad. Sci. USA 95:270.[Abstract/Free Full Text]
-
Mohagheghpour, N., Gammon, D., Kawamura, L. M., van Vollenhoven, A., Benike, C. J. and Engleman, E. G. 1998. CTL response to Mycobacterium tuberculosis: identification of an immunogenic epitope in the 19-kDa lipoprotein. J. Immunol. 161:2400.[Abstract/Free Full Text]
-
Zugel, U. and Kaufmann, S. H. 1997. Activation of CD8+ T cells with specificity for mycobacterial heat shock protein 60 in Mycobacterium bovis bacillus Calmette-Guerin-vaccinated mice. Infect. Immun. 65:3947.[Abstract]
-
van Crevel, R., Karyadi, E., Preyers, F., Leenders, M., Kullberg, B. J., Nelwan, R. H. and van der Meer, J. W. 2000. Increased production of interleukin 4 by CD4+ and CD8+ T cells from patients with tuberculosis is related to the presence of pulmonary cavities. J. Infect. Dis. 181:1194.[ISI][Medline]
-
Srikiatkhachorn, A. and Braciale, T. J. 1997. Virus-specific CD8+ T lymphocytes downregulate T helper cell type 2 cytokine secretion and pulmonary eosinophilia during experimental murine respiratory syncytial virus infection. J. Exp. Med. 186:421.[Abstract/Free Full Text]
-
Williams, N. S. and Engelhard, V. H. 1997. Perforin-dependent cytotoxic activity and lymphokine secretion by CD4+ T cells are regulated by CD8+ T cells. J. Immunol. 159:2091.[Abstract]
-
Rock, K. L. 1996. A new foreign policy: MHC class I molecules monitor the outside world. Immunol. Today 17:131.[ISI][Medline]
-
Jondal, M., Schirmbeck, R. and Reimann, J. 1996. MHC class I-restricted CTL responses to exogenous antigens. Immunity 5:295.[ISI][Medline]
-
Mazzaccaro, R. J., Gedde, M., Jensen, E. R., van Santen, H. M., Ploegh, H. L., Rock, K. L. and Bloom, B. R. 1996. Major histocompatibility class I presentation of soluble antigen facilitated by Mycobacterium tuberculosis infection. Proc. Natl Acad. Sci. USA 93:11786.[Abstract/Free Full Text]
-
Banchereau, J. and Steinman, R. M. 1998. Dendritic cells and the control of immunity. Nature 392:245.[ISI][Medline]
-
Henderson, R. A., Watkins, S. C. and Flynn, J. L. 1997. Activation of human dendritic cells following infection with Mycobacterium tuberculosis. J. Immunol. 159:635.[Abstract]
-
Behar, S. M., Dascher, C. C., Grusby, M. J., Wang, C. R. and Brenner, M. B. 1999. Susceptibility of mice deficient in CD1d or TAP1 to infection with Mycobacterium tuberculosis. J. Exp. Med. 189:1973.[Abstract/Free Full Text]