|
|||||||||
|
|
|
|
|
|
|
|
|
|
|
Prepublished online as a Blood First Edition Paper on June 28, 2002; DOI 10.1182/blood-2001-11-0080.
IMMUNOBIOLOGY
From the Laboratory of AIDS Immunopathogenesis,
Divisions of Immunology and Allergy and Infectious Diseases, Department
of Medicine, and Institute of Microbiology, Centre Hospitalier
Universitaire Vaudois, University of Lausanne, Switzerland; the
Division of Infectious Diseases, San Raffaele Institute, Milan, Italy;
and the Laboratory of Virology, University of Geneva, Switzerland.
CD4 T-cell-specific memory antiviral responses to human
immunodeficiency virus type 1 (HIV-1) and cytomegalovirus (CMV) were investigated in 16 patients with documented primary HIV-1 infection (4 of the 16 subjects also had primary CMV infection) and compared with
those observed in patients with chronic HIV-1 and CMV coinfection. Virus-specific memory CD4 T cells were characterized on the basis of
the expression of the chemokine receptor CCR7. HIV-1- and CMV-specific interferon- Previous studies performed in mice and humans
have clearly highlighted the critical role of virus-specific CD4 T
cells in the control of chronic viral infections.1-13 In
particular, CD4 proliferative responses are generally not detected
during primary infection3,14 or in patients with chronic
infection, with the exception of patients with nonprogressive disease
("long-term nonprogressors").1-5,15 Recent studies
have linked the lack of immune control of human immunodeficiency virus
1 (HIV-1) infection to the absence of CD4 proliferation, that is, the
helper function.3 Initiation of antiviral treatment during
the early phase of acute infection may lead to restoration of the
virus-specific CD4 helper response and may be associated with partial
control of virus replication during chronic infection.3
Despite the lack of virus-specific CD4 helper response, HIV-1-specific
CD4 T cells have been identified even in patients with progressive
disease on the basis of their ability to secrete interferon (IFN)- With regard to primary infection, little is known about the
presence of IFN- Patients
The 7 patients with chronic HIV-1 infection were naive to
antiviral therapy (CD4 T-cell count Fluorescence-activated cell sorter (FACS) analysis and sorting
Determination of CMV DNA in plasma and of HIV-1 cellular viral load CMV viremia was measured with a modified version of the Amplicor CMV Monitor test (Roche Diagnostic, Indianapolis, IN), with a limit of detection of 10 DNA copies per milliliter of plasma.21Cell-associated HIV-1 DNA and RNA in sorted
CD4+CCR7+ and
CD4+CCR7 HIV-1- and CMV-specific lymphoproliferation assays Peripheral blood mononuclear cells (PBMCs) were thawed and resuspended at 37°C in RPMI 1640 Gutamax-1 medium containing 2% inactivated AB human serum. PBMCs were plated at 1 × 105 cells per well in U-bottom 96-well cell culture plates (Costar, Bucks, United Kingdom) and incubated with HIV-1 p55 and p24 gag proteins (1 µg per well) and/or CMV lysates (1:2000 final concentration) for 5 days. Then cell cultures were pulsed with [3H]thymidine (1.0 µCi [.037 MBq] per well) for 18 hours. Cell cultures with a stimulation index of 5 or higher compared with the unstimulated control cell cultures were considered to be positive for HIV-1- and/or CMV-specific proliferation.Cytokine detection Intracellular cytokine production was assessed as previously described.5 PBMCs (3-4 × 106 cells in 2 mL) were stimulated with 10 µg (5 µg per mL final concentration) of p55 or gp160 HIV-1 proteins (Protein Sciences, Meriden, CT) and/or 1:200 final dilution CMV lysates (Bio Whittaker Verviers, Belgium) and/or 200 ng/mL staphylococcal enterotoxin B (positive control), or phosphate-buffered saline (PBS) for unstimulated negative controls for 6 hours at 37°C. Stimulation was performed in the presence 0.5 µg/mL of purified anti-CD28 antibody (Becton Dickinson) and, as of the second hour, with 10 µg/mL Brefeldin A (Sigma, St Louis, MO). Cell surface staining was completed as described following the 6-hour in vitro activation. Cells were then permeabilized with Intrastain (Dako, Glostrup, Denmark) and labeled with antihuman IFN- APC (IgG1, B27; Pharmingen, San Diego, CA). Simultaneously, activation was assessed by staining with anti-CD69 FITC (Becton Dickinson). Since the mean percentage background in the unstimulated cultures was less than 0.02, background levels were
not subtracted.
Statistical analysis Statistical significance (P values) of the results was calculated by 2-tailed t test.
Patients All the patients included in the present study experienced an acute viral clinical syndrome of variable severity19 at the time of primary HIV-1 infection. The most common symptoms were fever, asthenia, fatigue, diarrhea, and lymphoadenopathy. The laboratory criteria for the diagnosis of primary infection were the presence of HIV-1 RNA plasma viremia, negative or weakly positive antibody tests, and less than 3 bands at Western blot. These stringent laboratory criteria allowed us to identify the patients during the early phase of primary infection, as indicated by mean number of days (17.4) from the onset of symptoms to the time of the diagnosis and by the high levels of HIV-1 plasma viremia (mean 6.251.000 HIV-1 RNA copies per milliliter of plasma) (Table 1).CMV serology and CMV plasma viremia were determined in the majority of patients; CMV serology was not determined in 1 patient. On the basis of CMV serology we identified 3 groups of patients: (1) patients with negative serology for CMV (5 of 15); (2) patients with high-avidity IgG anti-CMV, typical of chronic CMV infection (6 of 15) and no history of CMV-associated disease; and (3) patients with IgM anti-CMV and no IgG antibodies, an antibody profile typical of CMV seroconversion (4 of 15) (Table 2). The 4 patients with CMV seroconversion also had substantial levels of CMV viremia at the time of the diagnosis of primary infection (Table 1). These latter patients had no signs of CMV-associated organ disease, although there was a trend toward statistical significance for a lower percentage of CD4 T cells (mean 9.75% ± 6.3%, n = 4) compared with the patients with no CMV primary infection (mean 19.6% ± 11.7%, n = 12, P = .07) (Table 1). Therefore, these results indicate that these 4 patients experienced primary HIV-1 and CMV coinfection. Phenotypic analysis of CD4 T cells Previous studies have shown that the chemokine receptor CCR7 defines distinct subsets of naive and memory T lymphocytes with different homing and effector capacities.16-18 In particular, CD4 and CD8 T lymphocyte populations lacking CCR7 contain the majority of cells with potential effector function as defined by the secretion of IFN- and by the expression of
perforin.18 In this regard, it has been recently shown
that CD8 T lymphocytes are mostly contained within the
CCR7 T lymphocyte subset.16
To characterize the CD4 T-cell response during primary HIV-1 infection,
in preliminary experiments we analyzed PBMCs obtained from 9 HIV-negative subjects, 13 HIV-1-infected subjects with chronic
infection, and 15 subjects with primary infection with monoclonal antibodies to CD4 and CCR7. These analyses were performed on
PBMCs collected prior to the initiation of therapy. In Figure 1A, representative examples for the 3 groups studied are shown. These analyses showed that the CD4 cell
population lacking CCR7 appeared to be increased in the patients with
primary HIV-1 infection. The mean percentage of
CD4+CCR7
A large percentage of CD4+CCR7 Functional analysis of different populations of virus-specific memory CD4 T cells As mentioned above, CD4 and CD8 T cells with effector function are contained within the cell populations lacking CCR7.16-18 To delineate the antiviral-specific primary CD4 T-cell-mediated immune response, we assessed the ability of the different populations of CD4 T cells, as defined by the expression and/or the absence of CCR7, to secrete IFN-. Patients 1 through 4 also had primary CMV infection
(Tables 1 and 2). IFN--secreting cells were detected in 12 of 13 patients studied (Table 1). The assessment of HIV-1-specific CD4 T
cells was mostly performed following stimulation of blood mononuclear
cells with p55 gag HIV-1 protein; assessment of CMV-specific CD4 T
cells was performed following stimulation with CMV lysates. As shown in
Figure 2 and Table 1, in 4 representative
patients selected on the basis of CMV serology (CMV primary infection
[patients 3 and 4], chronic CMV infection [patient 8], and negative
CMV serology [patient 14]), the majority (> 90%) of
CD4+ IFN--secreting cells were contained within the
CCR7 cell population. The mean percentage of
CD4+CCR7 IFN--secreting cells was
significantly lower (0.49% ± 0.47%, n = 12; Table 1) than
the mean percentage of CMV-specific CD4+CCR7
T cells observed in the 4 patients with CMV primary infection (mean
percentage 7.2% ± 6.3%, n = 4, P = .003;
Table 1).
A possible explanation for the differences in the magnitude of HIV-1-
and CMV-specific CD4 T-cell responses was that HIV-1-specific CD4
T-cell response might be directed against HIV-1 proteins other than
gag. To test this hypothesis, PBMCs were also stimulated with gp160
envelope HIV-1 protein. No evidence was found for the presence of a
substantial percentage of env-specific CD4 T cells in patients with
primary infection (data not shown). Because only a percentage higher
than 0.03% of IFN- Another possible explanation of the difference in magnitude of primary HIV-1- and CMV-specific CD4 T-cell responses that we observed is that CMV viral lysate was used to assess CMV-specific responses, whereas either p55 or gp160 proteins were used to assess HIV-specific responses. It has been shown that CD4+ T-cell responses to the CMV pp65 protein often account for as little as 10% of the response obtained by stimulation with viral lysates,25 despite the fact that pp65 is known to be the major target of the CMV T-cell response. Therefore, it is not possible to exclude the possibility that the observed differences in magnitude of CMV and primary immune responses were dependent upon the type of antigen stimulation (eg, viral lysate vs protein). We then analyzed whether there were differences between primary CMV-
and HIV-1-specific CD4 T-cell responses and those in patients with
chronic CMV and HIV-1 coinfection. CMV-specific memory CD4 T-cell
responses were determined in 13 patients with chronic CMV infection. We
determined that 6 patients with primary HIV-1 infection and 7 with
chronic HIV-1 infection also had chronic CMV infection. The patients
with chronic HIV-1 infection were at early stages of the disease and
had had no previous antiviral treatment; the mean plasma viremia was
32 000 HIV-1 RNA copies per milliliter, the mean CD4 T-cell count was
952 ± 254 per µL of blood, and the mean CD4 T-cell percentage was
36.3% ± 7%. CMV-specific CD4+ IFN- Therefore, these results indicate that a major expansion of virus-specific CD4 T cells is associated with primary CMV but not with HIV-1 infection. The magnitude of primary HIV-1-specific CD4 T-cell response is indeed not significantly different from that observed during chronic infection. The differences in magnitude between primary and chronic HIV-1- and CMV-specific immune responses may translate into differences in effectiveness of the 2 antiviral responses in the control of virus replication. In this regard, it is important to underscore that CMV replication was efficiently (within 2 to 4 weeks) suppressed in the patients experiencing CMV primary infection even in the absence of specific anti-CMV therapy, and CMV viremia was rapidly below 10 DNA copies per milliliter of plasma (data not shown). With regard to the antigen-specific proliferative responses, blood mononuclear cells were stimulated with p24 and p55 gag HIV-1 proteins and with CMV lysates. HIV-1-specific proliferative responses were rarely detected (2 of 13 patients) during primary infection (Table 1). Similarly, CMV-specific proliferative responses were not detected in the 13 patients with primary HIV-1 infection (Table 1). The lack of detection of virus-specific proliferative responses during primary HIV-1 infection is not surprising. Previous studies performed by the Walker and McElrath groups3,14 have clearly demonstrated that these responses are suppressed during primary HIV-1 infection and are eventually restored only after early initiation of antiviral therapy and effective suppression of HIV-1 replication and resolution of the acute phase of infection. Analysis of HIV-1 viral load in different populations of memory CD4 T cells Blood CD4+CCR7 and
CD4+CCR7+ T-cell populations were isolated by
cell sorting and analyzed for cellular HIV-1 viral load. We found that
a substantial proportion of CD4+CCR7 T cells
were infected with HIV-1, as indicated by the presence of viral DNA and
RNA (Figure 3). The levels of viral load
were consistently found to be higher (in the range of 0.5 log for both HIV-1 DNA and RNA, P = .02) in the
CD4+CCR7 cell population than in the
CD4+CCR7+ cell subset.
Previous studies of patients with chronic HIV-1 infection have
shown the presence of HIV-1-specific CD4 T cells as measured by the
secretion of IFN- In the present study, we have taken advantage of the recent
characterization of the complexity of the antigen-specific memory CD4
T-cell response in HIV-1-negative healthy subjects17,18 and the delineation of the memory CD8 T-cell response.16
To assess the memory CD4 T-cell response, we used the expression of the
chemokine receptor CCR7 as a tool to identify different populations of
memory virus-specific CD4 T cells. With this strategy, we have
demonstrated that the majority of CD4 T cells, as measured by the
ability to secrete IFN- Furthermore, previous studies showed that CCR7 Four of 16 patients experienced primary HIV-1 and CMV infections, as is unequivocally shown by the pattern of the CMV antibody response (Table 2). The results show a substantial difference in the magnitude of the effector HIV-1-specific T-cell response (significantly lower) compared with the CMV-specific CD4 T-cell response. However, as mentioned above, the possibility cannot be ruled out that these differences resulted from the different types of antigen stimulation used for CMV (eg, viral lysates) and HIV-1 (eg, p55 or gp160 proteins). Recent studies have indicated that stimulation with viral lysates may be more efficient than stimulation with proteins.25 There was no evidence for an expansion of effector HIV-1-specific CD4 T cells during primary infection, since their percentage was comparable to that found during chronic infection. In contrast, the pool of effector CMV-specific CD4 T cells was significantly expanded during primary CMV infection. These results raise the issue of the potential mechanisms responsible
for the observed lack of expansion of HIV-1-specific CD4 T cells
during the primary immune response. One potential mechanism may be
related to poor immunogenicity of HIV-1, which, in turn, may
result in a weak CD4 T-cell immune response. This explanation, however,
is not supported by the massive expansion of HIV-1-specific CD8 T
cells invariably associated with primary HIV-1
infection.31 Another possibility is that HIV-1-specific CD4 T cells are accumulated in the lymphoid tissue. Previous studies have shown, however, that there is no evidence for accumulation in the
lymphoid tissue of HIV-1-specific CD8 T cells at the time of primary
infection.32 A more likely hypothesis is that a larger proportion of effector HIV-1-specific CD4 T cells are infected with
HIV-1 during primary infection. This hypothesis was consistent with the
finding that a substantial proportion of HIV-1-specific CD4 T cells
were contained within the CCR7 The differences in viral load between the 2 cell populations appear too
small to propose that one population may serve as the preferential
reservoir for HIV-1. However, these results certainly provide evidence
that a large proportion of CD4+CCR7 On the basis of the data from the present study, the likely scenario is that the expansion of effector HIV-1-specific CD4 T cells during primary infection is aborted by the infection of a large proportion of virus-specific CD4 T cells. Interestingly, HIV-1-specific CD4 T cells are depleted preferentially, because HIV-1 infection does not seem to prevent the expansion of CMV-specific CD4 T cells. However, 2 recent studies in mice have clearly demonstrated that both CD4 and CD8 T cells with effector function accumulate in the target organ of the pathogen.33,34 The target organ of HIV-1 is the lymphoid tissue.35 Thus HIV-1-specific CD4 T cells are preferentially eliminated, since they mediate their effector function in the anatomic site that serves as the primary site of virus replication.35 Lungs, salivary glands, cervix, and/or retina are the target organs of CMV. Therefore, on the basis of the studies in mice we would expect a substantial proportion of HIV-1-specific CD4 and CD8 T cells with effector function to accumulate in the lymphoid tissue (eg, lymph nodes), whereas CMV-specific CD4 and CD8 T cells with effector function should accumulate away from the lymphoid tissue. Therefore, the likely reason CMV-specific CD4 T cells can expand is because they will rapidly exit from the lymphoid tissue to migrate to the anatomic sites where CMV replicates (lungs, salivary glands, cervix, and/or retina) and therefore will escape HIV infection. In this regard, we recently compared the distribution of HIV- and CMV-specific CD4 and CD8 T cells in blood and lymph nodes of HIV-1- and CMV-coinfected individuals with chronic infection (all the patients studied had CD4 T-cell counts > 500/µL and were naive to antiretroviral therapy). This analysis clearly demonstrated that a very low proportion of CMV-specific CD4 and CD8 T lymphocytes reside in the lymph nodes as compared with the blood (the frequency of CMV-specific T cells was at least 1 log higher in blood).35 In contrast, the distribution of HIV-specific CD4 and CD8 T cells was almost identical between blood and lymph nodes.36 These results further support the critical role played by CD4 T cells in antiviral immune response,1-13 provide advances in the delineation of virus-specific memory CD4 T-cell responses and in the potential mechanisms of the defect of the CD4 T-cell response in HIV-1 infection, and reinforce the importance of the initiation of antiviral therapy in primary HIV-1 infection to preserve virus-specific CD4 T-cell immune response.3
Submitted November 20, 2001; accepted April 8, 2002.
Prepublished online as Blood First Edition Paper, June 28, 2002; DOI 10.1182/blood-2001-11-0080.
Supported by research grants from the Swiss National Foundation (3100-66788-01) and from the National Institutes of Health (001 A1-G1535)
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: Giuseppe Pantaleo, Laboratory of AIDS Immunopathogenesis, Department of Medicine, Centre Hospitalier Universitaire Vaudois, University of Lausanne, 1011 Lausanne, Switzerland; e-mail: giuseppe.pantaleo{at}chuv.hospvd.ch.
1.
Kalams SA, Walker BD.
The critical need for CD4 help in maintaining effective cytotoxic T lymphocyte responses.
J Exp Med.
1998;188:2199-2204
2.
Kalams SA, Buchbinder SP, Rosenberg ES, et al.
Association between virus-specific cytotoxic T-lymphocyte and helper responses in human immunodeficiency virus type 1 infection.
J Virol.
1999;73:6715-6720 3. Rosenberg ES, Altfeld M, Poon SH, et al. Immune control of HIV-1 after early treatment of acute infection. Nature. 2000;407:523-526[CrossRef][Medline] [Order article via Infotrieve].
4.
Rosenberg ES, Billingsley JM, Caliendo AM, et al.
Vigorous HIV-1-specific CD4+ T cell responses associated with control of viremia.
Science.
1997;278:1447-1450 5. Pitcher CJ, Quittner C, Peterson DM, et al. HIV-1-specific CD4+ T cells are detectable in most individuals with active HIV-1 infection, but decline with prolonged viral suppression. Nat Med. 1999;5:518-525[CrossRef][Medline] [Order article via Infotrieve].
6.
Matloubian M, Concepcion RJ, Ahmed R.
CD4+ T cells are required to sustain CD8+ cytotoxic T-cell responses during chronic viral infection.
J Virol.
1994;68:8056-8063
7.
Battegay M, Moskophidis D, Rahemtulla A, Hengartner H, Mak TW, Zinkernagel RM.
Enhanced establishment of a virus carrier state in adult CD4+ T-cell-deficient mice.
J Virol.
1994;68:4700-4704
8.
Oxenius A, Price DA, Easterbrook PJ, et al.
Early highly active antiretroviral therapy for acute HIV-1 infection preserves immune function of CD8+ and CD4+ T lymphocytes.
Proc Natl Acad Sci U S A.
2000;97:3382-3387 9. Malhotra U, Berrey MM, Huang Y, et al. Effect of combination antiretroviral therapy on T-cell immunity in acute human immunodeficiency virus type 1 infection. J Infect Dis. 2000;181:121-131[CrossRef][Medline] [Order article via Infotrieve]. 10. von Herrath MG, Yokoyama M, Dockter J, Oldstone MB, Whitton JL. CD4-deficient mice have reduced levels of memory cytotoxic T lymphocytes after immunization and show diminished resistance to subsequent virus challenge. J Virol. 1996;70:1072-1079[Abstract].
11.
Zajac AJ, Blattman JN, Murali-Krishna K, et al.
Viral immune evasion due to persistence of activated T cells without effector function.
J Exp Med.
1998;188:2205-2213 12. Gerlach JT, Diepolder HM, Jung MC, et al. Recurrence of hepatitis C virus after loss of virus-specific CD4(+) T-cell response in acute hepatitis C. Gastroenterology. 1999;117:933-941[CrossRef][Medline] [Order article via Infotrieve].
13.
Lechner F, Wong DK, Dunbar PR, et al.
Analysis of successful immune responses in persons infected with hepatitis C virus.
J Exp. Med.
2000;191:1499-1512 14. Musey LK, Krieger N, Hughes P, Schaker TW, Corey L, McElrath MJ. Early and persistent human immunodeficiency virus type 1 (HIV-1)specific T helper dysfunction in blood and lymph nodes following acute HIV-1 infection. J Infect Dis. 1999;180:278-284[CrossRef][Medline] [Order article via Infotrieve]. 15. Altfeld M, Rosenberg ES. The role of CD4(+) T helper cells in the cytotoxic T lymphocyte response to HIV-1. Curr Opin Immunol. 2000;12:375-380[CrossRef][Medline] [Order article via Infotrieve]. 16. Champagne P, Ogg GS, King AS, et al. Skewed maturation of memory HIV-specific CD8 T lymphocytes. Nature. 2001;410:106-111[CrossRef][Medline] [Order article via Infotrieve]. 17. Sallusto F, Mackay CR, Lanzavecchia A. The role of chemokine receptors in primary, effector, and memory immune responses. Annu Rev Immunol. 2000;18:593-620[CrossRef][Medline] [Order article via Infotrieve]. 18. 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].
19.
Kahn JO, Walker BD.
Acute human immunodeficiency virus type 1 infection.
N Engl J Med.
1998;339:33-39 20. Bart PA, Rizzardi GP, Tambussi G, et al. Immunological and virological responses in HIV-1 infected adults at early stage of established infection treated with highly active antiretroviral therapy. AIDS. 2000;13:1887-1897. 21. Yerly S, Rutschmann OT, Opravil M, Marchal F, Hirschel B, Perrin L. Cell-associated HIV-1 RNA in blood as indicator of virus load in lymph nodes. J Infect Dis. 1999;180:850-850[CrossRef][Medline] [Order article via Infotrieve]. 22. Berger EA, Murphy PM, Farber JM. Chemokine receptors as HIV-1 coreceptors: roles in viral entry, tropism, and disease. Annu Rev Immunol. 1999;17:657-700[CrossRef][Medline] [Order article via Infotrieve]. 23. Loetscher P, Uguccioni M, Bordoli L, et al. CCR5 is characteristic of Th1 lymphocytes. Nature. 1998;391:344-345[Medline] [Order article via Infotrieve]. 24. Gerdes J, Lemke H, Baisch H, Wacker HH, Schwab U, Stein H. Cell cycle analysis of a cell proliferation-associated human nuclear antigen defined by the monoclonal antibody Ki-67. J Immunol. 1984;33:1710-1715. 25. Maecker HT, Dunn HS, Suni MA, et al. Use of overlapping peptide mixtures as antigens for cytokine flow cytometry. J Immunol Methods. 2001;255:27-40[CrossRef][Medline] [Order article via Infotrieve]. 26. Komanduri KV, Feinberg J, Hutchins RK, et al. Loss of cytomegalovirus-specific CD4+ T cell responses in human immunodeficiency virus type 1-infected patients with high CD4+ T cell counts and recurrent retinitis. J Infect Dis. 2001;183:1285-1289[CrossRef][Medline] [Order article via Infotrieve]. 27. Komanduri KV, Donahoe SM, Moretto WJ, et al. Direct measurement of CD4+ and CD8+ T-cell responses to CMV in HIV-1-infected subjects. Virology. 2001;279:459-470[CrossRef][Medline] [Order article via Infotrieve].
28.
Autran B, Carcelain G, Li TS, et al.
Positive effects of combined antiretroviral therapy on CD4+ T cell homeostasis and function in advanced HIV disease.
Science.
1997;277:112-116 29. Rizzardi GP, Tambussi G, Bart PA, Chapuis A, Lazzarin A, Pantaleo G. Virological and immunological responses to HAART in asymptomatic therapy-naive HIV-1-infected subjects according to CD4 cell count. AIDS. 2000;15:2257-2263. 30. Tough DF, Borrow P, Sprent J. Induction of bystander T cell proliferation by viruses and type I interferon in vivo. Science. 1996;272:1947-1950[Abstract]. 31. Pantaleo G, Demarest JF, Soudeyns H, et al. Major expansion of CD8+ T cells with a predominant V beta usage during the primary immune response to HIV. Nature. 1994;370:463-467[CrossRef][Medline] [Order article via Infotrieve]. 32. Pantaleo G, Soudeyns H, Demarest JF, et al. Accumulation of human immunodeficiency virus-specific cytotoxic T lymphocytes away from the predominant site of virus replication during primary infection. Eur J Immunol. 1997;27:3166-3173[Medline] [Order article via Infotrieve].
33.
Masopust D, Vezys V, Marzo AL, Lefrancois L.
Preferential localization of effector memory cells in nonlymphoid tissue.
Science.
2001;291:2413-2417 34. Reinhardt RL, Khoruts A, Merica R, Zell T, Jenkins MK. Visualizing the generation of memory CD4 T cells in the whole body. Nature. 2001;410:101-105[CrossRef][Medline] [Order article via Infotrieve]. 35. Pantaleo G, Graziosi C, Demarest JF, et al. HIV infection is active and progressive in lymphoid tissue during the clinically latent stage of disease. Nature. 1993;362:355-358[CrossRef][Medline] [Order article via Infotrieve]. 36. Ellefsen K, Harari A, Champagne P, Sekaly RP, Pantaleo G. Distribution and functional analysis of memory CD8 and CD4 T lymphocytes in different anatomic compartments. In: Program and Abstracts of the 9th Conference on Retroviruses and Opportunistic Infections; February 24-28, 2002; Seattle, WA. Abstract no. 234.
© 2002 by The American Society of Hematology.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Top
Abstract
Introduction
250 cells/µL, plasma
viremia 
fluorescein isothiocyanate (FITC) or 
