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IMMUNOBIOLOGY
From the Center for Blood Research and Department of
Pediatrics, Harvard Medical School, Boston, MA; Division of Infectious
Diseases, Department of Medicine, University Hospitals of Cleveland,
Case Western Reserve University, Cleveland, OH; Division of Infectious
Diseases and Geographic Medicine, Department of Medicine, New
England Medical Center, Tufts University School of Medicine, Boston,
MA; and Millennium Pharmaceuticals, Inc, Cambridge, MA.
CD8 T cells are classified as naïve, effector, or memory
cells on the basis of CD45RA, CD62L, and CCR7 expression. Sequential engagement of cell-surface CD62L and CCR7 receptors is required for
efficient trafficking to lymphoid tissue by means of high endothelial
venules. Naïve CD8 T cells are
CCR7+CD62L+ CD45RA+, whereas
long-term memory cells are
CCR7+CD62L+CD45RA The development of a class I-restricted CD8 T-cell
response in vivo is associated with changes in the cell-surface
phenotype of CD8 T cells that reflect alterations in the migration and
functional capability of these cells. Naïve T cells
continuously recirculate from blood to lymphoid tissue (lymph nodes
[LNs]) through specialized high endothelial venules (HEVs).
Sequential engagement of L-selectin (CD62L) and lymphocyte
function-associated antigen (LFA) 1 on naïve T cells to their
respective ligands, peripheral node addressin and intercellular
adhesion molecule (ICAM) 1 and ICAM-2, on HEV, sets into motion
tethering, rolling, and firm adhesion of T cells to HEVs Apart from their expression of adhesins, naïve, effector, and
memory cells can also be distinguished by their expression of proteins
important for their activation and function.13
Naïve cells express the RA isoform of CD45, are
CD28+ and CD27+, and do not express the
cytolytic effector molecules, perforin and granzymes. Although most
previously activated T cells are CD45RO+ and
CD45RA Infection with human immunodeficiency virus (HIV) stimulates one of the
strongest known human antiviral CD8 T-cell responses, with tremendous
expansion of previously activated CD8 T cells and a high frequency of
circulating HIV-specific CD8 T cells.14-18 Paradoxically,
despite their high frequency (estimated to be orders of magnitude
greater than the number of HIV-replicating targets19), CD8
T cells are unable to eradicate the virus or halt progressive immunodeficiency in most subjects with HIV infection not receiving antiviral drugs. CD8 T cells in HIV-infected subjects are
phenotypically heterogeneous.20 This heterogeneity likely
reflects each cell's unique history of antigen exposure (in a setting
of ongoing viral replication and chronic inflammation) and functional
capability. Some alterations in CD8 T cells may interfere with
effective antiviral immunity. Because HIV infection is concentrated in
LNs, lack of expression of molecules that target effector cytotoxic T
lymphocytes (CTLs) to the LNs might interfere with their ability to
provide protection. In fact, one study found a lack of perforin
expression, which is required for effective CTL-mediated lysis of
HIV-infected cells, in the LNs of HIV-infected subjects.21
In an effort to understand the reasons for the inadequate immune
protection in HIV infection, we compared the distribution and
functional potential of naïve, memory, and effector subsets of
CD8 T cells in healthy and HIV-infected subjects. We found that, in HIV
infection, there is a paucity of LN-homing naïve and long-term
memory cells, which is more profound in patients with acquired
immunodeficiency syndrome (AIDS). Antigen-specific CD8 T cells from
HIV-infected donors as well as those from healthy volunteers, stained
with tetramers for 3 viruses Subjects
Tetramers
Flow cytometry For external staining, PBMC (2-10 × 105/tube) were stained as previously described22 with the following fluorescein isothiocyanate-conjugated (FITC), phycoerythrin (PE)-conjugated, or Cy5-conjugated monoclonal antibodies (mAbs): CD8 (mAb B9.11; Immunotech, Marseille, France), CD45RA (mAb ALB11; Immunotech), or CD62L (mAb DREG-56; Pharmingen, San Diego, CA), or IgG-FITC, IgG-PE-conjugated, and IgG-Cy5-conjugated, isotype-matched controls (Immunotech). For CCR7 assessment, cells were stained with -human CCR7 mAb 7H12 (IgG2b produced to recombinant protein at
LeukoSite, Cambridge, MA) and then with PE-conjugated F(ab')2 goat antimouse Ig (Immunotech). After external
staining, cells were resuspended in 50 µL Hanks balanced salt
solution and permeabilized by using a Fix and Perm Kit (Caltag
Laboratories, Burlingame, CA) according to the manufacturer's protocol
before staining with FITC or PE-conjugated - granzyme A (GzmA)
mAb (CB9; Pharmingen) or -perforin mAb ( G9; Pharmingen). For
tetramer staining, PBMC (2 × 106) were resuspended in
500 µL fluorescence-activated cell-sorter (FACS) buffer and stained
for 40 minutes at 4°C with 0.5 µg/mL streptavidin
PE-conjugated tetramers. The cells were washed and resuspended in FACS
buffer for costaining with the mAbs described above. Stained cells were
resuspended in 50 µL FACS buffer and 2% formaldehyde for analysis on
a CD8bright tightly gated lymphocyte population
(FACScalibur; Becton Dickinson, Mountain View, CA). Gates were defined
by requiring that fewer than 1% of the isotype-control
antibody-stained cells were positive.
Statistical analysis Data from donors with HIV infection were analyzed for significant differences from data from healthy volunteers by using the 2-tailed Student t test and the nonparametric Mann-Whitney test. All analyses were also done to determine whether there were significant correlations with Centers for Disease Control (CDC)-defined disease stage32 and plasma viremia.
Reduction of naïve and long-term memory cells and expansion of effector and effector memory T cells in HIV infection We compared the CD8 T-cell subset distribution, defined by CCR7, CD45RA, and CD62L expression, in 14 HIV-infected subjects at various stages of disease (5 with CDC stage A, 5 with stage B, and 4 with stage C) with that in healthy donors (Figure 1). There was a marked reduction in circulating CCR7+ CD8 T cells in HIV-infected donors compared with healthy donors, particularly in patients with AIDS. Whereas 60% ± 9% of healthy donor CD8 T cells were CCR7+, only 17% ± 11% of CD8 T cells from HIV-infected donors expressed this LN-homing molecule (P < .0001). The proportions of CCR7+ CD8 T cells were similar in infected donors with stage A disease and those with stage B (21% ± 6% and 22% ± 9%, respectively) but decreased considerably in those with advanced stage C disease (4% ± 4%).
Previous studies showed a reduced proportion of circulating
naïve CD8 T cells (defined as
CD62L+CD45RA+) in HIV infection, which becomes
more pronounced with advanced disease.33 In our study, the
proportions of both CCR7+CD45RA+ naïve
cells and CCR7+CD45RA A similar analysis was done for coexpression of CCR7 and CD62L in
circulating CD8 T cells. Two thirds of CD8 T cells in HIV-infected donors (63% ± 15%) lacked both LN-homing molecules, whereas fewer than one third in healthy donors were
CCR7 GzmA and perforin are not coordinately expressed in CD8 T cells Perforin expression and granzyme expression have generally been thought to be up-regulated in parallel when CD8 T cells differentiate into effector CTLs.34 It is likely that GzmA, the most abundant granzyme in CTLs, continues to be expressed in many previously activated cells, since GzmA was found to be expressed in circulating CD8 T cells from healthy donors in proportion to the numbers of circulating CD8 T cells that were not naïve.35 However, the kinetics of perforin expression after effector cell differentiation has not been studied. We therefore assessed perforin and GzmA expression in circulating CD8 T cells costained for CCR7, CD45RA, and CD62L (Figure 2, Figure 3, and Table 2). In 5 healthy donors, there was a 4.5-fold excess of GzmA-positive (GzmA+) CD8 T cells compared with perforin-positive (perforin+) CD8 T cells; 27% ± 8% of CD8 T cells were GzmA+, whereas only 6% ± 2% were perforin+ (P < .01). Most CD8 T cells that were not naïve (because they no longer expressed CCR7, CD45RA, or CD62L) stained for GzmA. Of CCR7 cells, 69% ± 7% were GzmA+.
Similarly, 63% ± 9% of CD45RA cells and
84% ± 2% of CD62L cells were GzmA+.
CCR7+ CD8 T cells, which include naïve and
long-term memory cells, uniformly did not express perforin in samples
from healthy donors. Only 0.4% ± 0.4% of CCR7+ cells
were perforin+, whereas 3.2% ± 1.6% were
GzmA+. Therefore, the cells that homed to the LNs had no
immediate cytotoxic capability.
Perforin staining results do not support the designation of effector and effector memory populations based on CD45RA expression When perforin and GzmA staining were done in conjunction with CD45RA staining in samples from healthy donors, there were many more GzmA+ cells than perforin+ cells in both the CD45RA+ and CD45RA subsets. We found 3 times
as many GzmA+ CD45RA+ cells as
perforin+ CD45RA+ cells and 6 times as many in
the CD45RA subset. Therefore, although a larger
proportion of the GzmA+ CD45RA+ cells were
perforin+, at least two thirds of the GzmA+
CD45RA+ cells did not stain for perforin and are therefore
unlikely to be cytolytic without additional changes in protein
expression. The highest concentration of perforin+ CD8 T
cells in healthy donors were CD62L (32% ± 3%; Figure
3 and Table 2). These results suggest that the assignment of
CCR7CD62LCD45RA+ T cells as
effector CTLs13,20 may be somewhat justified but is an
oversimplification. Because perforin expression is absolutely required
for granule-mediated cytolysis, some
CCR7CD45RA cells are effector CTLs, whereas
most CCR7CD45RA+ CD8 T cells are unlikely to
be immediately cytotoxic without additional differentiation.
Increase of GzmA+ and perforin+ CD8 T cells in HIV infection The proportion of GzmA- and perforin-expressing CD8 T cells in HIV-infected donors was substantially greater than that in healthy donors, again with more cells expressing GzmA than perforin. In donors with HIV infection, 67% ± 21% of CD8 T cells were GzmA+ (P < .001 versus results in healthy donors), whereas 34% ± 21% were perforin+ (P < .01 versus results in healthy donors). The number of perforin+ CD8 T cells appeared to increase with disease severity, but the differences were not significant in this small sample. As in samples from healthy donors, virtually no CCR7+ CD8 T cells expressed perforin (1.5% ± 1.0%). However, a small proportion of CCR7+ CD8 T cells in samples from HIV-infected donors expressed GzmA (15% ± 12% versus 3% ± 2% in healthy donors; Figures 2 and 3 and Table 2). This suggests that long-term memory cells have down-modulated perforin but that GzmA expression is less tightly regulated and may persist in some central memory cells as they traffic to the LNs. In healthy donors, the distribution of perforin- and GzmA-expressing cells analyzed for coexpression of the other LN-homing marker CD62L was similar to that for CCR7. CD62L+ cells generally did not express perforin, although the results were not as uniform as those in CCR7+ cells. However, in samples from HIV-infected donors, most CD62L+ cells were GzmA+ and, in some of these donors, a good proportion (19% ± 21%) also expressed perforin.Perforin was expressed in many CD45RA+ and
CD45RA Antigen-specific CD8 T cells do not express CCR7 and most are also
CD62L
Few tetramer+ CD8 T cells recognizing HIV, EBV, or CMV
antigens stained for the chemokine receptor CCR7 (Figure
5). Of 25 samples costained for tetramer
and CCR7, 15 had no tetramer+ cells staining for CCR7. Only
one sample (for an EBV tetramer in a sample from a healthy donor) had
any substantial number of cells with detectable CCR7 expression. The
other LN-homing molecule, CD62L, was more often expressed on
tetramer+ cells but was still only present in fewer than
one third of tetramer+ cells, except in the sample with a
higher frequency of CCR7 staining. In that sample, 33% of
tetramer+ EBV-specific CD8 T cells expressed CCR7 and 60%
expressed CD62L. The pattern of CD62L staining on samples from healthy
donors was similar to that on samples from HIV-seropositive donors.
HIV-specific CD8 T cells, unlike EBV- and CMV-specific T cells, do not express CD45RA Because CD45RA expression may be linked to effector CTL function, we also stained tetramer+ cells for CD45RA. In HIV-seropositive donors, only 5.1% ± 5.7% of HIV-tetramer+ cells expressed CD45RA, whereas 35.3% ± 22.8% of EBV- or CMV-specific cells from the same subject group were CD45RA+ (Figure 5); the difference was significant (P < .004). The proportion of EBV- and CMV-specific cells that were CD45RA+ in samples from healthy donors (33.7% ± 22.8%) was similar to that in samples from HIV-seropositive donors. Because only 5 of the 13 HIV-infected subjects studied had tetramer-staining cells above background levels for both HIV and non-HIV tetramers, we also graphed CCR7, CD62L, and CD45RA expression in the tetramer+ cells from those 5 donors (Figure 6). Although levels of CCR7 and CD62L expression for HIV-specific and non-HIV-specific cells were comparable, there was substantially more CD45RA expression in the EBV- and CMV-specific cells than in the HIV-specific cells when each donor was considered individually.
Antigen-specific CD8 T cells are decreased in PLN compared to blood Because tetramer+ cells did not express CD62L and CCR7, molecules required for interaction with PLN HEVs, we investigated whether tetramer+ cells were reduced in peripheral lymph nodes (PLN) compared with blood. Paired blood and PLN aspirate samples were obtained from 2 HLA B8-positive, HIV-seropositive asymptomatic subjects not currently receiving antiretroviral drugs. Samples from both donors stained for B8 EBV tetramers but not for B8 HIV tetramers. We therefore compared the distribution of total CD8 T cells and EBV-tetramer+ cells in PBMC and PLN. CD62L and CCR7 CD8 T cells were more than
2-fold more frequent in PBMC than in PLN (Figure
7). Correspondingly, there were only half
as many CD8+ T cells in PLN as were found in PBMC.
These results indicate that although
CD62L+CCR7+ CD8 T cells preferentially home to
PLN, CD62LCCR7 cells are selectively
impaired in reaching PLN. This was also strikingly reflected in the
distribution of tetramer+ cells. There were proportionately
3- to 4-fold fewer EBV-tetramer+ CD8 T cells in PLN than in
PBMC (Figure 7). Even within the CD8 subset, there were approximately
2-fold fewer tetramer+ cells in PLN than PBMC (0.4% versus
0.8% in sample A and 0.5% versus 0.8% in sample B; data not shown).
Expression of CD62L, CCR7, CD45RA, CD27, and CD28 by
EBV-tetramer+ cells was comparable in the 2 sets of PLN and
PBMC samples (data not shown).
Although HIV infection stimulates one of the strongest known human antiviral CD8 T-cell responses,14-17 CD8 T cells fail to control disease progression in most infected people. Our results suggest a possible important factor contributing to the inability of CD8 T cells to control HIV: failure of HIV-specific CD8 T cells to express the homing receptors required for efficient trafficking into LNs where most HIV replication occurs. This lack of LN-homing molecules is not restricted to HIV-specific CD8 T cells or to HIV infection, since CMV- and EBV-specific cells from both healthy donors and HIV-infected donors had the same trafficking receptor patterns of expression. Therefore, antigen-experienced CD8 T cells in the setting of chronic infection with persistent antigenemia may be selectively excluded from the LNs, even when the infection is localized primarily to those tissues. The initial activation of naïve CD8 T cells occurs in T-cell
zones of LNs where the naïve T cell encounters dendritic cells bearing the peptide antigen that fits its antigen receptor. Therefore, naïve T cells are equipped with adhesion molecules such as
L-selectin and CCR7, whose sequential engagement are required for
access to LNs. However, on activation, T cells down-regulate L-selectin and up-regulate adhesion molecules such as In the absence of L-selectin and CCR7, CD8 T cells generally do not
bind to HEVs. In HIV infection, where there is a reduction in
CCR7+CD62L+ circulating CD8 T cells, one might
expect that relatively fewer CD8 T cells would traffic to the LNs. In
fact, in 2 subjects we tested, the frequency of CD8 T cells in PLN was
only half of that in PBMC, and the number of EBV-tetramer+
cells in PLN was reduced even further The exclusion of effector cells from LNs, which in normal circumstances provides efficient division of labor among CD8 T cells and may protect LNs from immunopathological damage by inflammatory cytokines and cytolytic enzymes, may work to the detriment of the host in HIV infection by converting LNs into relatively immunologically privileged sites. A study of acute simian immunodeficiency virus (SIV) infection in macaques also suggested that SIV-specific CD8 T cells are preferentially excluded from the LNs.38 In blood and LN samples from monkeys obtained 13 and 21 days after SIV infection, there were proportionately 4-fold fewer SIV-tetramer+ cells in LNs than in the circulation (P < .007). This is remarkably similar to what we found for EBV-tetramer+ cells in 2 subjects with chronic HIV infection. Clearly, lack of CCR7 and CD62L is not an absolute bar to LN trafficking. In fact, gene-marked, HIV-specific CD8 T-cell clones adoptively transferred into HIV-infected subjects were shown to traffic to LN,39 but how efficiently they can do this is uncertain, since billions of T cells were infused in this clinical study. It is not clear whether the infused cells expressed L-selectin and CCR7, but such expression is unlikely after prolonged in vitro culture. The distribution of naïve and memory CD8 T-cell subsets is
grossly altered in HIV-seropositive subjects. Naïve CD8 T
cells, which express CD45RA, L-selectin, and CCR7, were decreased
markedly in such subjects and nearly absent in patients with stage C
disease. On the basis of differential expression of homing receptors,
different subsets of human memory CD8 T cells have been proposed:
L-selectin-positive, CD45RA In contrast to naïve and central memory cells, both
CD45RA+CCR7 Although CD45RA expression may be an imperfect marker for effector CTLs, our finding that CD45RA is virtually absent from HIV-specific CD8 T cells but not from EBV- or CMV- specific cells in the same HIV-infected donors raises the possibility that terminal differentiation into fully competent effector cells may be defective in HIV-specific CD8 T cells. This idea is in accord with our earlier observation that CD8 T cells in HIV-seropositive subjects have defects in HIV-specific cytolytic ability,35 a finding that was confirmed by subsequent studies.22,40 Moreover, perforin is selectively not expressed in LNs during acute and chronic HIV infection, although GzmA is.21 Consistent with the hypothesis of incomplete differentiation is the finding that HIV-tetramer+ cells in the periphery also lack perforin expression and do not down-regulate expression of CD27.22,40 An important observation in this study is that perforin and granzymes were not coordinately expressed. In both healthy and HIV-infected donors, there was a large excess of CD8 T cells that expressed GzmA but not perforin. The granule-mediated pathway, which is critical for immune defense against many viral infections, depends absolutely on the presence of perforin. Mice that have been rendered genetically deficient in perforin succumb to infections with such viruses as lymphocytic choriomeningitis virus.43 Moreover, HIV-infected primary T cells are lysed exclusively by the perforin-dependent granule-mediated pathway.44 Therefore, although perforin and granzyme expression are up-regulated in tandem during the initial differentiation of naïve CD8 T cells into effector CTLs,34 their subsequent expression is not tightly linked and perforin expression is likely to be the controlling factor for cytotoxicity. A report of a striking lack of perforin expression in HIV-specific CD8 T cells compared with other CD8 T cells suggests that perforin expression might be distinctively affected by HIV infection.40 However, this finding must be confirmed. The lack of effective immune surveillance by antigen-specific CD8 T
cells in HIV infection is likely to be multifactorial (Figure
8). Some researchers have postulated the
importance of defects in target cell recognition by HIV-specific CTLs
because of down-modulation of MHC class I molecules on infected cells by nef or because of viral mutations of CTL epitopes to evade recognition or inhibit a functional response.45,46 Several possible molecular mechanisms on HIV-specific CD8 T cells that may
contribute to lack of an effective response when an HIV-infected cell
is recognized have also been described. These are (1) down-modulation of the key T-cell signaling molecules CD3
We thank Brooke Harnisch and Zhan Xu for excellent technical help, Michael Lederman and the Case Western Reserve Center for AIDS Research for assistance in obtaining LN samples, and the National Institute of Allergy and Infectious Diseases Reagent and Reference Repository for providing us with most of the tetramers used in this study.
Submitted December 6, 2000; accepted March 8, 2001.
Supported by National Institutes of Health grants AI-42519 and AI-45406 to J.L. and AI-45306 to P.S.
G.C. and P.S. contributed equally to this work.
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Judy Lieberman, Center for Blood Research, 800 Huntington Ave, Boston, MA 02115; e-mail: lieberman{at}cbr.med.harvard.edu.
1. Springer TA. Traffic signals for lymphocyte recirculation and leukocyte emigration: the multistep paradigm. Cell. 1994;76:301-314[CrossRef][Medline] [Order article via Infotrieve]. 2. Butcher EC, Picker LJ. Lymphocyte homing and homeostasis. Science. 1996;272:60-66[Abstract].
3.
Nakano H, Mori S, Yonekawa H, Nariuchi H, Matsuzawa A, Kakiuchi T.
A novel mutant gene involved in T-lymphocyte-specific homing into peripheral lymphoid organs on mouse chromosome 4.
Blood.
1998;91:2886-2895 4. Forster R, Schubel A, Breitfeld D, et al. CCR7 coordinates the primary immune response by establishing functional microenvironments in secondary lymphoid organs. Cell. 1999;99:23-33[CrossRef][Medline] [Order article via Infotrieve].
5.
Stein JV, Rot A, Luo Y, et al.
The CC chemokine thymus-derived chemotactic agent 4 (TCA-4, secondary lymphoid tissue chemokine, 6Ckine, exodus-2) triggers lymphocyte function-associated antigen 1-mediated arrest of rolling T lymphocytes in peripheral lymph node high endothelial venules.
J Exp Med.
2000;191:61-76
6.
Campbell JJ, Bowman EP, Murphy K, et al.
6-C-kine (SLC), a lymphocyte adhesion-triggering chemokine expressed by high endothelium, is an agonist for the MIP-3
7.
Tangemann K, Gunn MD, Giblin P, Rosen SD.
A high endothelial cell-derived chemokine induces rapid, efficient, and subset-selective arrest of rolling T lymphocytes on a reconstituted endothelial substrate.
J Immunol.
1998;161:6330-6337
8.
Mackay CR, Marston WL, Dudler L.
Naive and memory T cells show distinct pathways of lymphocyte recirculation.
J Exp Med.
1990;171:801-817 9. Vitetta ES, Berton MT, Burger C, Kepron M, Lee WT, Yin XM. Memory B and T cells. Annu Rev Immunol. 1991;9:193-217[CrossRef][Medline] [Order article via Infotrieve]. 10. Gray D. Immunological memory. Annu Rev Immunol. 1993;11:49-77[CrossRef][Medline] [Order article via Infotrieve]. 11. Swain SL, Croft M, Dubey C, et al. From naive to memory T cells. Immunol Rev. 1996;150:143-167[CrossRef][Medline] [Order article via Infotrieve]. 12. Sallusto F, Lenig D, Forster R, Lipp M, Lanzavecchia A. Two subsets of memory T lymphocytes with distinct homing potentials and effector functions. Nature. 1999;401:708-712[CrossRef][Medline] [Order article via Infotrieve].
13.
Hamann D, Baars PA, Rep MH, et al.
Phenotypic and functional separation of memory and effector human CD8+ T cells.
J Exp Med.
1997;186:1407-1418 14. Walker BD, Chakrabarti S, Moss B, et al. HIV-specific cytotoxic T lymphocytes in seropositive individuals. Nature. 1987;328:345-348[CrossRef][Medline] [Order article via Infotrieve]. 15. Plata F, Autran B, Martins LP, et al. AIDS virus-specific cytotoxic T lymphocytes in lung disorders. Nature. 1987;328:348-351[CrossRef][Medline] [Order article via Infotrieve]. 16. Hoffenbach A, Langlade-Demoyen P, Dadaglio G, et al. Unusually high frequencies of HIV-specific cytotoxic T lymphocytes in humans. J Immunol. 1989;142:452-462[Abstract].
17.
Altman JD, Moss PAH, Goulder PJR, et al.
Phenotypic analysis of antigen-specific T lymphocytes.
Science.
1996;274:94-96
18.
Gea-Banacloche JC, Migueles SA, Martino L, et al.
Maintenance of large numbers of virus-specific CD8+ T cells in HIV-infected progressors and long-term nonprogressors.
J Immunol.
2000;165:1082-1092 19. Lieberman J. Cytotoxic T lymphocyte adoptive immunotherapy for HIV infection. In: Sitkovsky MV,Henkart PA, eds. Cytotoxic cells: Basic Mechanisms and Medical Applications. Philadelphia, PA: Lippincott Williams and Wilkins; 1999:441-457. 20. Roederer M, De Rosa S, Gerstein R, et al. Eight-color, 10-parameter flow cytometry to elucidate complex leukocyte heterogeneity. Cytometry. 1997;29:328-339[CrossRef][Medline] [Order article via Infotrieve]. 21. Andersson J, Behbahani H, Lieberman J, et al. Perforin is not co-expressed with granzyme A within cytotoxic granules in CD8 T lymphocytes present in lymphoid tissue during chronic HIV infection. AIDS. 1999;13:1295-1303[CrossRef][Medline] [Order article via Infotrieve].
22.
Shankar P, Russo M, Harnisch B, Patterson M, Skolnik P, Lieberman J.
Impaired function of circulating HIV-specific CD8+ T cells in chronic human immunodeficiency virus infection.
Blood.
2000;96:3094-3101 23. Johnson RP, Trocha A, Yang L, et al. HIV-1 gag-specific cytotoxic T lymphocytes recognize multiple highly conserved epitopes: fine specificity of the gag-specific response defined by using unstimulated peripheral blood mononuclear cells and cloned effector cells. J Immunol. 1991;147:1512-1521[Abstract].
24.
Ogg GS, Jin X, Bonhoeffer S, et al.
Quantitation of HIV-1-specific cytotoxic T lymphocytes and plasma load of viral RNA.
Science.
1998;279:2103-2106
25.
Walker BD, Flexner C, Paradis TJ, et al.
HIV-1 reverse transcriptase is a target for cytotoxic T lymphocytes in infected individuals.
Science.
1988;240:64-66 26. Shankar P, Fabry JA, Fong DM, Lieberman J. Three regions of HIV-1 gp160 contain clusters of immunodominant CTL epitopes. Immunol Lett. 1996;52:23-30[CrossRef][Medline] [Order article via Infotrieve]. 27. Wills MR, Carmichael AJ, Mynard K, et al. The human cytotoxic T-lymphocyte (CTL) response to cytomegalovirus is dominated by structural protein pp65: frequency, specificity, and T-cell receptor usage of pp65-specific CTL. J Virol. 1996;70:7569-7579[Abstract]. 28. Engstrand M, Tournay C, Peyrat MA, et al. Characterization of CMVpp65-specific CD8+ T lymphocytes using MHC tetramers in kidney transplant patients and healthy participants. Transplantation. 2000;69:2243-2250[CrossRef][Medline] [Order article via Infotrieve]. 29. Singhal S, Shaw JC, Ainsworth J, et al. Direct visualization and quantitation of cytomegalovirus-specific CD8+ cytotoxic T-lymphocytes in liver transplant patients. Transplantation. 2000;69:2251-2259[CrossRef][Medline] [Order article via Infotrieve].
30.
Steven NM, Annels NE, Kumar A, et al.
Immediate early and early lytic cycle proteins are frequent targets of the Epstein-Barr virus-induced cytotoxic T cell response.
J Exp Med.
1997;185:1605-1617
31.
Callan MFC, Tan L, Annels N, et al.
Direct visualization of antigen-specific CD8+ T cells during the primary immune response to Epstein-Barr virus in vivo.
J Exp Med.
1998;187:1395-1402 32. 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. Centers for Disease Control. MMWR Morb Mortal Wkly Rep. 1993;41:1-19. 33. Roederer M, Dubs JG, Anderson MT, Raju PA, Herzenberg LA. CD8 naive T cell counts decrease progressively in HIV-infected adults. J Clin Invest. 1995;95:2061-2066. 34. Garcia-Sanz JA, Velotti F, MacDonald HR, Masson D, Tschopp J, Nabholz M. Appearance of granule-associated molecules during activation of cytolytic T-lymphocyte precursors by defined stimuli. Immunology. 1988;64:129-134[Medline] [Order article via Infotrieve].
35.
Trimble LA, Lieberman J.
Circulating CD8 T lymphocytes in human immunodeficiency virus-infected individuals have impaired function and downmodulate CD3 36. Lieberman J, Fabry JA, Fong DM, Parkerson GR 3rd. Recognition of a small number of diverse epitopes dominates the cytotoxic T lymphocytes response to HIV type 1 in an infected individual. AIDS Res Hum Retroviruses. 1997;13:383-392[Medline] [Order article via Infotrieve].
37.
Warnock RA, Campbell JJ, Dorf ME, Matsuzawa A, McEvoy LM, Butcher EC.
The role of chemokines in the microenvironmental control of T versus B cell arrest in Peyer's patch high endothelial venules.
J Exp Med.
2000;191:77-88
38.
Kuroda MJ, Schmitz JE, Charini WA, et al.
Emergence of CTL coincides with clearance of virus during primary simian immunodeficiency virus infection in rhesus monkeys.
J Immunol.
1999;162:5127-5133 39. Brodie SJ, Lewinsohn DA, Patterson BK, et al. In vivo migration and function of transferred HIV-1-specific cytotoxic T cells. Nature Med. 1999;5:34-41[CrossRef][Medline] [Order article via Infotrieve].
40.
Appay V, Nixon DF, Donahoe SM, et al.
HIV-specific CD8+ T cells produce antiviral cytokines but are impaired in cytolytic function.
J Exp Med.
2000;192:63-75
41.
Baars PA, Ribeiro Do Couto LM, Leusen JH, et al.
Cytolytic mechanisms and expression of activation-regulating receptors on effector-type CD8+CD45RA+CD27
42.
Pittet MJ, Speiser DE, Valmori D, Cerottini JC, Romero P.
Cutting edge: cytolytic effector function in human circulating CD8+ T cells closely correlates with CD56 surface expression.
J Immunol.
2000;164:1148-1152 43. Kagi D, Ledermann B, Burki K, et al. Cytotoxicity mediated by T cells and natural killer cells is greatly impaired in perforin-deficient mice. Nature. 1994;369:31-37[CrossRef][Medline] [Order article via Infotrieve].
44.
Shankar P, Xu Z, Lieberman J.
Viral-specific cytotoxic T lymphocytes lyse HIV-infected primary T lymphocytes by the granule exocytosis pathway.
Blood.
1999;94:3084-3093 45. Collins KL, Chen BK, Kalams SA, Walker BD, Baltimore D. HIV-1 Nef protein protects infected primary cells against killing by cytotoxic T lymphocytes. Nature. 1998;391:397-401[CrossRef][Medline] [Order article via Infotrieve]. 46. Phillips RE, McMichael AJ. How does the HIV escape cytotoxic T cell immunity? Chem Immunol. 1993;56:150-164[Medline] [Order article via Infotrieve].
47.
Saukkonen JJ, Kornfeld H, Berman JS.
Expansion of a CD8+CD28
48.
Borthwick NJ, Bofill M, Gombert WM, et al.
Lymphocyte activation in HIV-1 infection, II; functional defects of CD28 49. Lewis DE, Tang DS, Adu-Oppong A, Schober W, Rodgers JR. Anergy and apoptosis in CD8+ T cells from HIV-infected persons. J Immunol. 1994;153:412-420[Abstract]. 50. Stefanova I, Saville MW, Peters C, et al. HIV infection-induced posttranslational modification of T cell signaling molecules associated with disease progression. J Clin Invest. 1996;98:1290-1297[Medline] [Order article via Infotrieve].
51.
Geertsma MF, van Wengen-Stevenhagen A, van Dam EM, et al.
Decreased expression of
52.
Trimble LA, Shankar P, Patterson M, Daily JP, Lieberman J.
Human immunodeficiency virus-specific circulating CD8 T lymphocytes have down-modulated CD3
53.
De Maria A, Ferraris A, Guastella M, Pilia S, et al.
Expression of HLA class I-specific inhibitory natural killer cell receptors in HIV-specific cytolytic T lymphocytes: impairment of specific cytolytic functions.
Proc Natl Acad Sci U S A.
1997;94:10285-10288
54.
Trimble LA, Kam LW, Friedman RS, Xu Z, Lieberman J.
CD3
© 2001 by The American Society of Hematology.
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|
|
|
|
|
|
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|
|
|
|
 |
|
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|
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|
 |
|
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|
|
|
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|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
 |
|
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|
|
|
|
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|
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|
|
|
|
 |
|
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|
|
|
|
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|
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|
|
|
|
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|
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|
|
|
|
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|
|
|
|
|
|
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|
|
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|
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|
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|
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|
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|
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|
|
|
|
|
|
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|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
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|
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|
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|
|
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|
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|
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J. Lieberman, P. Shankar, N. Manjunath, and J. Andersson Dressed to kill? A review of why antiviral CD8 T lymphocytes fail to prevent progressive immunodeficiency in HIV-1 infection Blood, September 15, 2001; 98(6): 1667 - 1677. [Abstract] [Full Text] [PDF]
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Top
Abstract
Introduction
steps that
are prerequisite for transmigration of these cells into the surrounding
LNs.
1, 
indicates NI; 
,
HIV+.
and CD28 on HIV-specific CD8 T cells with corresponding anomalies in signaling recognition of
antigen,