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The Journal of Immunology, 2002, 168: 3477-3483.
Copyright © 2002 by The American Association of Immunologists

Reduced Functional Capacity of CD8+ T Cells Expanded by Post-Exposure Vaccination of {gamma}-Herpesvirus-Infected CD4-Deficient Mice1

Haiyan Liu2, Samita Andreansky, Gabriela Diaz, Twala Hogg and Peter C. Doherty

Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN 38105


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Mice (I-Ab-/-) that lack CD4+ T cells remain healthy for at least three months after respiratory exposure to the murine {gamma}-herpesvirus 68 ({gamma}HV68), then succumb with symptoms of chronic wasting disease. Postexposure challenge of {gamma}HV68-infected I-Ab+/+ and I-Ab-/- mice with a recombinant vaccinia virus (Vacc-p56) expressing an antigenic {gamma}HV68 peptide caused a massive increase in the numbers of Dbp56-specific CD8+ T cells. Previous experiments showed that, despite the large numbers of potential CTL effectors, there was little effect on the long-term survival of the CD4-deficient group and no diminution in the level of persistent virus shedding and latency. Comparison of the expanded CD8+Dbp56+ sets in the I-Ab+/+ and I-Ab-/- mice indicated that these two T cell populations were not identical. More CD69highCD8+ Dbp56+ T cells were found in the CD4-deficient mice, an effect that might be thought to reflect higher Ag load. By contrast, the mean fluorescence intensity of staining for the CD44 glycoprotein was diminished on CD8+Dbp56+ T cells from the I-Ab-/- group, the level of CTL activity was lower on a per cell basis, and the relative prevalence of IFN-{gamma}+TNF-{alpha}+ T cells detected after in vitro stimulation with the p56 peptide was decreased. Given that this experimental system provides an accessible model for evaluating postexposure vaccination protocols that might be used in diseases like HIV/AIDS, the further need is to clarify the underlying molecular mechanisms and the relative significance of lack of CD4+ T help vs higher Ag load for these expanded CD8+ effector populations.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
Infection with the {gamma}-herpesviruses ({gamma}HV)3 is characterized by an acute phase of virus replication infection in mucosal sites, followed by life-long latency in B lymphocytes and other cell types (1, 2). The progressive loss of CD4+ T cells in HIV/AIDS is associated with enhanced shedding of EBV (the prototypic human {gamma}HV) from the oropharynx and greatly increased incidence of the {gamma}HV-associated tumors, lymphoma and Kaposi’s sarcoma (1, 2, 3, 4, 5). This ultimately lethal escape of EBV and human herpesvirus 8-induced oncogenesis from immune control could reflect the loss of CD4+ effectors and/or a progressive decline in CD4+ T help for CD8+ CTL populations (6). Much of the recent focus on the design of EBV vaccines has been on priming the CD8+ T cell response, though it is likely that the incorporation of epitopes recognized by CD4+ T cells will also be important (7).

The reactivation of lytic {gamma}HV replication in human AIDS can be modeled (8, 9) by the intranasal (i.n.) challenge of CD4-deficient I-Ab-/- mice (10) with the closely related (11, 12) murine {gamma}-herpesvirus 68 ({gamma}HV68). Though the level of productive {gamma}HV68 infection in lung epithelium (13) is significantly limited by the CD8+ T cell response and the I-Ab-/- mice remain clinically normal for ~100 days, all eventually succumb to a late-onset, fatal wasting disease (8). Evidence of persistent, though relatively low level, virus production is found in the respiratory tract, while substantial numbers of latently infected B cells and macrophages (14, 15) are detected consistently in the lymphoid compartment (8).

Both conventional I-Ab+/+ and Ig-/- µMT (16) mice deal with the lytic phase of {gamma}HV68 replication within 10 days of respiratory exposure, progressively limit the numbers of latently infected B cells and macrophages, and remain clinically normal (17, 18, 19, 20). Long-term treatment of the Ig-/- mice with subset-specific mAbs has shown that either CD4+ or CD8+ populations can mediate partial, though not complete, control of this infection (21). The CD4+ T cells were found to operate via an IFN-{gamma}-dependent mechanism, while the CD8+ T cells were not further compromised in CD4-depleted mice that were also treated with a mAb to IFN-{gamma}. However, this demonstration of a likely role for IFN-{gamma}-producing CD4+ T cell effectors (21) does not preclude the possibility that CD4+ T help is also important for the CD8+ T cell response.

The two most prominent peptides recognized by responding CD8+ T cells in H2b mice infected with {gamma}HV68 are derived from a ssDNA-binding protein (p56) and a ribonucleotide reductase (p79), presented in the context of H2Db and H2Kb, respectively (20, 22). Postexposure vaccination (23) of {gamma}HV68-infected I-Ab+/+ and I-Ab-/- mice with a recombinant vaccinia virus (24) expressing p56 (Vacc-p56) massively expanded the CD8+ T cell population specific for the Dbp56 epitope. However, the numbers of CD8+ T cells that could be stained with a tetrameric complex of H2Db and the p56 peptide (Dbp56 tetramer) declined progressively in both the I-Ab+/+ and I-Ab-/- mice (23). Furthermore, the infection was not controlled and the onset of the fatal {gamma}HV68-induced wasting disease was only slightly delayed in the boosted I-Ab-/- group. Limited analysis of the CD8+Dbp56+ T cells in clinically compromised I-Ab-/- mice indicated that at least some could still synthesize IFN-{gamma}. The overall impression was that, unlike the situation (25, 26, 27) in CD4-deficient mice infected with the nonlytic lymphocytic choriomeningitis virus (LCMV), these {gamma}HV-68-specific CD8+ T cells were not functionally impaired (23). We have now looked much more closely at the events following postexposure challenge (23) of {gamma}HV68-infected I-Ab+/+ and I-Ab-/- mice and have found that Dbp56-specific CD8+ T cells expanded in the absence of concurrent CD4+ T help show evidence of diminished activation.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Mice

Female C57BL/6J (B6, I-Ab+/+) mice (The Jackson Laboratory, Bar Harbor, ME) and MHC class II-deficient (I-Ab-/-) mice (Charles River Breeding Laboratories, Worcester, MA) were kept under specific pathogen-free conditions at St. Jude Children’s Research Hospital (Memphis, TN). The genotype of the I-Ab-/- mice (10) was verified by eye bleed and flow cytometry. Age-matched 8- to 12-wk-old mice were used at the initial priming phase of all experiments.

Virus infection and sampling

The mice were anesthetized with Avertin (2, 2, 2-tribromoethanol; Sigma-Aldrich, St. Louis, MO) and infected i.n. with 1 x 104 pfu of {gamma}HV68 (8). Some were then given 5 x 107 pfu of Vacc-p56 i.p. at least 6 wk after the primary infection. Both the construction of the Vacc-p56 recombinant incorporating the AGPHNDMEI (p56) epitope and the kinetics of the secondary response in persistently infected I-Ab+/+ and I-Ab-/- mice have been described previously (23, 24). At time of sampling, the mice were anesthetized with Avertin and bled from the right axillary artery (28). Blood was collected in tubes containing heparin (1000 U/ml; Elkins-Sinn, Cherry Hill, NJ), the inflammatory population was recovered from the lung by bronchoalveolar lavage (BAL) and single-cell suspensions were made from the mediastinal lymph nodes (MLN) and spleen (28). The PBL were separated on a 1-Step gradient (Accurate Chemical and Scientific, Westbury, NY) by centrifugation for 30 min at 2000 rpm. Lymphocytes were collected from the interface and washed, and residual erythrocytes were lysed with ammonium chloride. The BAL cells were adhered to plastic for 1 h at 37°C to remove macrophages and monocytes. The BAL, PBL, and MLN populations were pooled from five to six mice, while the spleens were analyzed from individuals.

Analysis of cell staining profiles

Spleen and MLN populations were enriched for the CD8+ set by in vitro depletion with mAbs to I-Ab (M5/114.15.2) and CD4 (GK1.5), followed by sheep-anti-rat Ig and sheep-anti-mouse Ig-coated magnetic beads (Dynal Biotech, Oslo, Norway). Virus-specific CD8+ T cells were stained with PE-labeled Dbp56 or Kbp79 tetrameric complexes (22) at room temperature, followed by anti-CD8{alpha}-Tricolor (Caltag Laboratories, South San Francisco, CA) and conjugated mAbs (BD PharMingen, San Diego, CA) specific for various phenotypic markers (CD69, LFA-1, CD44, CD62L) that are associated with lymphocyte activation (29, 30). Unenriched spleen and MLN populations were also stained with anti-CD8{alpha}-FITC and anti-CD4-PE, to verify the I-Ab-/- mice and to allow the total counts for CD8+Dbp56+ T cells to be determined for the particular lymphoid organ. A limited analysis of perforin expression profiles used Dbp56+ T cells that were fixed in 1% formalin, permeabilized with 0.1% saponin, then stained with anti-perforin (Kamiya Biomedical, Seattle, WA) and goat anti-rat Ig-FITC (BD PharMingen). All lymphocytes were stained and washed in ice-cold PBS containing BSA (0.1%) and azide (0.01%) and analyzed on a FACScan or FACSCaliber using CellQuest software (BD Biosciences, Mountain View, CA).

Flow cytometric analysis of cytokine production by p56-specific CD8+ T cells

The various CD8+ T cell populations were incubated with peptide (1 µM) for 5 h at 37°C in the presence of brefeldin A (10 µg/ml) and IL-2 (50 U/ml) before staining with anti-CD8{alpha}-FITC (22). The lymphocytes were then fixed with formalin (1%), permeabilized by saponin (0.5%), and stained for intracellular cytokine with anti-IFN{gamma}-PE and anti-TNF-{alpha} allophycocyanin (BD PharMingen) for flow cytometric analysis.

Measurement of CTL activity

The level of CTL activity was determined using a standard 5 h 51Cr release assay (31). The EL-4 (H2b) targets were incubated with peptide (p56, 10 µg/ml) and 51Cr (300 µCi) at 37°C for 1 h, washed and cocultured at 104/well with spleen cells at different E:T ratios. The supernatants were then harvested for gamma counting. Maximum release (M) was determined by adding Triton X-100 (1%) to the targets, while the level of spontaneous release (S) was for targets cultured in the absence of effector cells. The level of specific 51Cr release was calculated as: the percentage of specific release = (counts - S)/(M - S), where counts are the experimental 51Cr release in the presence of immune CD8+ T cells.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Quantitation of the primary response to {gamma}HV68 and the expansion by Vacc-p56 challenge

The profiles of clonal expansion and persistence for the CD8+Kbp79+ and CD8+Dbp56+ populations were essentially equivalent following primary i.n. exposure of naive I-Ab+/+ and I-Ab-/- mice to {gamma}HV68 (Table IGo). The relative prevalence of the CD8+ subset is, because of the absence of CD4+ T cells, inevitably increased in the I-Ab-/- lymphoid tissue. This is to some extent reflected (Table IGo) in the CD8+Kbp79+ (day 10) and CD8+Dbp56+ (day 40) frequencies. Even so, despite the fact that the {gamma}HV68-infected I-Ab-/- mice show evidence of persistent virus replication in the respiratory tract and higher levels of latency in the spleen (8, 23), the numbers of {gamma}HV68-specific CD8+ T cells present on day 40 in the spleen and blood were similar to those in the I-Ab+/+ controls.


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  		Table I. Characteristics of the primary response

 
Challenging {gamma}HV68-infected mice (Table IGo) with Vacc-p56 accentuated the tendency for the percentage of p56-specific CD8+ T cells determined by both tetramer staining (Fig. 1Go, top panels) and restimulation with peptide (Fig. 1Go, bottom panels) to be higher in the I-Ab-/- group, though this did not translate into significant differences in the numbers of CD8+Dbp56+ spleen cells (middle panels, Fig. 1Go). However, the disease status of these two groups of mice was, as time progressed, very different. By day 60 after Vacc-p56, which is >100 days after the primary exposure to {gamma}HV68, many of the boosted I-Ab-/- mice were showing symptoms of the characteristic lethal wasting disease (8, 23). Also, despite the difference in disease status, the prevalence of virus-specific CD8+ T cells fell equivalently by day 60 for the I-Ab-/- and I-Ab+/+ groups (Fig. 1Go).



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  		FIGURE 1. Quantitative analysis of the secondary Dbp56-specific CD8+ T cell response. The B6 I-Ab+/+ and I-Ab-/- mice were infected i.n. with 104 pfu {gamma}HV-68 1 mo before i.p. challenge with 5 x 107 pfu of Vacc-p56. The percentage of Dbp56+CD8+ cells was determined by tetramer staining while intracellular IFN-{gamma} staining was measured after 5 h of in vitro stimulation with 1 µM of the p56 peptide. Spleen populations were enriched for the CD8+ set and each data point shows the mean ± SD for five mice. The asterisk designates groups that were significantly different (p < 0.05). The MLN, PBL, and BAL samples were pooled.

 
Differences in activation phenotype for the CD8+Dbp56+ T cells

The intensity of CD44 staining for CD8+Dbp56+ T cells from individual spleens and pooled BAL samples taken at various times after i.p. exposure to Vacc-p56 is illustrated in Fig. 2Go. The profiles (Fig. 2Go) show clearly that the CD8+Dbp56+ set from the I-Ab-/- mice tends to express less CD44. Analyzing mean fluorescence intensity (MFI) for groups of five spleens at each time point established that this difference was significant at days 10, 20, and 60 after secondary challenge (Table IIGo, column 1). The same effect can be seen when the results are compared as ratios (I-Ab+/+:I-Ab-/-) for several experiments, with the diminution in the I-Ab-/- group being most obvious on days 10 and 20 for the spleen and day 10 for the BAL (Table IIGo).



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  		FIGURE 2. Profiles of CD44 staining for the secondarily stimulated CD8+Db p56+ set. The mice were primed and boosted as described in the footnote to Fig. 1Go. The quantitative analysis of MFI values is shown in Table IIGo.

 

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  		Table II. Intensity of staining for secondarily stimulated CD8+ Dbp56+ T cells1

 
Lower levels of LFA-1 staining were also found for the CD8+Dbp56+ T cells recovered on day 10 from the spleens of the CD4-deficient mice, but this difference was not sustained in the longer term and the BAL population tended to express more LFA-1 (ratio, final column, Table IIGo). It is to be expected that the larger BAL population (Fig. 1Go) from the I-Ab-/- mice would be more activated, as there is continued productive infection in the lung (8, 23) in the absence of the CD4+ subset. No significant differences were seen in the staining profiles for CD62L, the {beta}7 integrin, CTLA4, IL-2R, or CD43 (data not shown).

Unlike the situation for CD44 and LFA-1, well-defined high and low peaks were seen in the CD69 staining profiles for the CD8+Dbp56+ set (data not shown). Both the percentage frequencies and the numbers of CD69highCD8+Dbp56+ T cells were consistently greater for spleen populations from the I-Ab-/- group, and the numbers were also significantly higher for the BAL population at all time points (Table IIIGo). By this criterion, there are relatively more activated virus-specific CD8+ T cells in the CD4-deficient mice, as might be expected because of the greater prevalence of latently infected cells (8, 23).


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  		Table III. Prevalence of CD69highCD8+ Db+p56 T cells

 
Diminished prevalence of p56-specific CD8+ T cells producing both IFN-{gamma} and TNF-{alpha}

The initial analysis of this postexposure vaccination protocol in I-Ab+/+ and I-Ab-/- mice showed little, if any, difference in the IFN-{gamma} staining profiles for CD8+ T cells stimulated for 5 h with 1 µM of the p56 peptide in the presence of brefeldin A (23). This observation has been confirmed and extended in the present study, which indicates that the frequencies of CD8+IFN-{gamma}+ T cells are generally higher in the spleen, PBL, and MLN of the CD4-deficient group (Figure 1Go, bottom panels, and Table IVGo). However, the percentage of CD8+IFN-{gamma}+ spleen cells (Fig. 1Go) does drop between days 40 and 60, when the I-Ab-/- group starts to show evidence of clinical compromise.


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  		Table IV. Relative distribution of IFN-{gamma}+TNF-{alpha}+ and IFN-{gamma}+TNF-{alpha}-CD8+ T cells

 
Experiments over the past two years with virus systems in which all Ag is thought to be eliminated after the acute phase of the response have shown that the percentage of CD8+ memory T cells that stain for both IFN-{gamma} and TNF-{alpha} increases with time after challenge (32, 33). We found that this also seems to be the case following the Vacc-p56 challenge of the {gamma}HV68-infected I-Ab+/+ and I-Ab-/- mice: the prevalence of CD8+IFN-{gamma}+TNF-{alpha}+ T cells was higher (p < 0.05 or less) in spleens sampled on days 40 or 60 rather than on day 10 (Table IVGo). However, the relative frequency of CD8+ T cells that make both IFN-{gamma}+ and TNF-{alpha}+ was significantly lower throughout in the CD4-deficient group (Fig. 3Go, Table IVGo). This was apparent for both the spleen (Fig. 3Go, Table IIIGo) and the BAL (Table IVGo) populations. Also, the MFI for both IFN-{gamma} and TNF-{alpha} was significantly less on day 10 for CD8+ T cells from the I-Ab-/- mice, with this difference being also apparent on day 60 for TNF-{alpha} (Table IVGo, footnote c). In general, it seems that there is either a pattern of greater CD4-dependence for the production of TNF-{alpha} vs IFN-{gamma} by CD8+ T cells, or the IFN-{gamma}+TNF-{alpha}+ cells are less prominent under conditions of greater Ag persistence.



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  		FIGURE 3. Characteristics of the IFN-{gamma} and TNF-{alpha} staining profiles for p56 peptide-stimulated CD8+ T cells. The mice were primed with {gamma}HV68 and boosted with Vacc-p56 as described in the footnote to Fig. 1Go. The CD8+ T cells were enriched from the spleen, stimulated for 5 h with 1.0 µm p56 peptide in the presence of brefeldin A, then fixed and stained for TNF-{alpha} and IFN-{gamma}. The relative prevalence of the IFN-{gamma}+TNF-{alpha}+ cells from the I-Ab+/+ and I-Ab-/- mice is summarized in Table IIIGo.

 
Continued CTL activity after the Vacc-p56 challenge

Substantial p56-specific CTL activity was maintained in the spleens of both the I-Ab+/+ and I-Ab-/- mice for the 60 days subsequent to the Vacc-p56 challenge (Fig. 4Go, a–d). The levels were generally equivalent for the two groups of spleen populations, though the I-Ab-/- set was significantly more potent on d10 (Fig. 4Go, a and b) at the lowest E:T ratio (7.3:1). However, when we corrected the percentage of 51Cr release values for the CD8+Dbp56+ T cell frequencies determined by flow cytometry, we found that the CD8+ effectors from the CD4-deficient mice were (on a per cell basis) significantly less active at the days 10, 20, and 60 timepoints (Fig. 4Go, e–h). Again, there was evidence of a decline between days 40 and 60, when the I-Ab-/- mice show evidence of clinical compromise. Staining for cytoplasmic perforin at the day 10 timepoint also showed that the MFI was lower in CD8+Dbp56+ spleen cells from the I-Ab-/- mice (8.1 ± 0.5 vs 13.2 ± 0.8). Thus, though a much higher Ag load is being maintained in the CD4-deficient group (8, 23), the individual T cells seem to be less potent CTL effectors.



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  		FIGURE 4. CTL activity of Dbp56-specific CD8+ T cells. The I-Ab+/+ and I-Ab-/- mice were primed and challenged as described in the footnote to Fig. 1Go. The spleen populations were tested directly ex vivo in a 5 h 51Cr release assay with p56-peptide pulsed, or control, EL4 targets. a–d, The 51Cr release data for whole spleen tested at the E:T ratios shown, while the 51Cr release values in e–h were corrected for the percentage of CD8+Dbp56-specific T cells.

 

   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
Postexposure vaccination has attractions as a potential clinical strategy for the treatment of both persistent virus infections and tumors (34, 35, 36). These (and previous) experiments (23) establish that a relatively modest immunization regime, a single dose of a recombinant vaccinia virus, can cause enormous expansion of virus-specific CD8+ T cells in mice that have effectively (I-Ab+/+) or partially (I-Ab-/-) controlled {gamma}HV68 infection. However, what we have learned so far is that it is not sufficient just to increase CD8+ T cell numbers. Despite the likelihood of continued antigenic stimulation in CD4-deficient mice (8, 9, 23), the CD8+ T cell counts still decline to the point where wasting and death ensues (23). If this reflects that there is an absolute need for CD4+ T cell effectors (21), there may be little that we can do with the {gamma}HV68 model to suggest approaches that could be useful in AIDS patients. Should, in contrast, the essential requirement be for continuing CD4+ T help (6, 37), it may be possible to develop some therapeutic protocol for providing the necessary cytokines and/or activated DCs (38, 39).

The available evidence indicates that {gamma}HV68-specific CD8+ T cells operate primarily by perforin or Fas-mediated cytotoxicity (40). This CTL effector mechanism is potentially subverted by the {gamma}HV68 K3 protein, which has been shown to reduce the half-life of nascent MHC class I glycoproteins and the diminished expression of {gamma}HV68 epitopes on the surface of infected fibroblasts (41). However, it is not known how important the K3 factor is in the epithelial cells that support the in vivo replication of {gamma}HV68. Also, no analysis is yet available of the possible effect of cytokines like TNF-{alpha} and IFN-{gamma} on Ag presentation, either in DCs or on {gamma}HV68-infected lung cells.

The expanded CD8+Dbp56+ T cell populations that we recovered from the spleens of Vacc-p56-boosted, CD4+ T cell-deficient I-Ab-/- mice showed three measures of relative deficiency when compared with those from the I-Ab+/+ controls. These were: decreased CD44 expression, lower levels of CTL activity (on a per cell basis) for peptide-pulsed targets, and a decrease in the relative prevalence of lymphocytes producing both IFN-{gamma} and TNF-{alpha}. In each case, the defect tended to be most apparent at the earliest (day 10) and the latest (day 60) timepoints. The difference between the I-Ab+/+ and I-Ab-/- mice on day 10 may be a measure of the need for CD4+ T help to promote the initial phase of clonal expansion and differentiation. The diminished capacity of the CD8+ effectors recovered on day 60 (day 100 after {gamma}HV68) could reflect a continuing need for CD4+ T help and/or the consequences of persistent antigenic stimulation (8, 23).

It has long been recognized that CD44 is up-regulated on activated, effector, and memory CD8+ T cells (42, 43, 44). Though all the CD8+Dbp56+ T cells recovered from the I-Ab+/+ and I-Ab-/- mice were CD44high, the intensity of staining was generally lower for those from the CD4+ T cell-deficient group. Recent cross-linking experiments indicate that CD44 is associated with CD4 and the CD3 complex on the surface of helper T cells, suggesting that there may be a functional relationship between the CD4-TCR and CD44 (45). In addition, CD44 is thought to be involved in cytoskeleton rearrangement and raft reorganization in T lymphocytes (46, 47). It is thus possible that the decreased expression of CD44 may affect both the character of TCR signaling and CTL function in CD8+ T cells.

Virus-specific CD8+ T cells recovered from mice persistently infected with LCMV, particularly under conditions of CD4+ T cell deficiency, show evidence of much greater dysfunction than that found in this study (27). These LCMV-specific CD8+tetramer+ T cells neither produce IFN-{gamma} nor mediate CTL activity. The difference is that naive mice depleted of both the CD4+ and CD8+ T cell subsets invariably die following infection with the cytopathic {gamma}HV68, while the essentially nonlytic LCMV induces a life-long carrier state. Thus, the LCMV Ag load can be enormous in mice that lack T cells, a situation that cannot be tolerated with {gamma}HV68 (21).

One study of HIV infection found that Ag-specific CD8+ T showed normal profiles of IFN-{gamma} production (48). However, there is other evidence that HIV-specific CD8+ T cells may be functionally defective (49). This includes incomplete signaling and activation (50), reduced perforin expression (51), and inefficient trafficking to the site of infection (52). Similar findings have been made for primates infected with SIV (53).

Evidence of defective virus-specific CD8+ T cell function was also found (54) in patients persistently infected with the hepatitis C virus (HCV). The HCV-specific CD8+ T cells showed reduced synthesis of IFN-{gamma} and TNF-{alpha} after stimulation with either mitogens or peptides. Even so, the results for the I-Ab+/+ mice in the present experiments suggest that, as there is no known CD4+ T cell defect in HCV infection, it might be worth trying postexposure vaccination as a therapeutic protocol. The potential danger would, of course, be the induction of acute CD8+ T cell-mediated immunopathology (55, 56).

Thus, the extent of the functional defect in virus-specific CD8+ T cells from persistently infected mice may reflect the interaction between the magnitude and quality of TCR-mediated and associated signaling events. The analysis of both CD8+ T cell turnover rates in normal and CD4-deficient mice indicates that the "memory" T cell pool is regularly stimulated by the reactivation of latent {gamma}HV68 to a lytic phase (57). The same is true for CD4+ T cells in I-Ab+/+ mice that have effectively controlled the infection (58). The Ag load (55) in the I-Ab-/- mice will be much higher as a consequence of the greater numbers of latently infected cells in the lymphoid tissue and the continued production of lytic virus in the respiratory tract (8, 23, 59). Though there is evidence of partial functional impairment, more CD8+ T cells are CD69high in the I-Ab-/- mice. The much greater amounts of virus that can be tolerated in CD4-deficient mice infected with the essentially nonlytic LCMV lead to a complete functional paralysis, though not to T cell deletion. Further analysis with the {gamma}HV68 model needs to address the relative significance of continued antigenic stimulation vs absence of CD4+ T cell help on the character of the CD8+ T cell response.


   Acknowledgments
 
We thank Vicki Henderson for assistance with the manuscript and Mahnaz Paktinat for technical support.


   Footnotes
 
1 This work was supported by National Institutes of Health Grant CA21765 and by the American Lebanese Syrian Associated Charities. Back

2 Address correspondence and reprint requests to Dr. Haiyan Liu, Department of Immunology, St. Jude Children’s Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105-2794. E-mail address: haiyan.liu{at}stjude.org Back

3 Abbreviations used in this paper: {gamma}HV, {gamma}-herpesvirus; i.n., intranasal; {gamma}HV68, murine {gamma}HV68; Vacc-p56, recombinant vaccinia virus expressing the p56 peptide; LCMV, lymphocytic choriomeningitis virus; BAL, bronchoalveolar lavage; MLN, mediastinal lymph node; HCV, hepatitis C virus. Back

Received for publication October 5, 2001. Accepted for publication January 28, 2002.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Rickinson, A. B., D. J. Moss. 1997. Human cytotoxic T lymphocyte responses to Epstein-Barr virus infection. Annu. Rev. Immunol. 15:405.[Medline]
  2. Moss, D. J., S. R. Burrows, S. L. Silins, I. Misko, R. Khanna. 2001. The immunology of Epstein-Barr virus infection. Philos. Trans. R. Soc. Lond. B Biol. Sci. 356:475.[Abstract/Free Full Text]
  3. Ganem, D.. 1995. AIDS: viruses, cytokines and Kaposi’s sarcoma. Curr. Biol. 5:469.[Medline]
  4. Boshoff, C., R. A. Weiss. 2001. Epidemiology and pathogenesis of Kaposi’s sarcoma-associated herpesvirus. Philos. Trans. R. Soc. Lond. B Biol. Sci. 356:517.[Abstract/Free Full Text]
  5. Moore, P. S., Y. Chang. 2001. Molecular virology of Kaposi’s sarcoma-associated herpesvirus. Philos. Trans. R. Soc. Lond. B Biol. Sci. 356:499.[Abstract/Free Full Text]
  6. Kalams, S. A., B. D. Walker. 1998. The critical need for CD4 help in maintaining effective cytotoxic T lymphocyte responses. J. Exp. Med. 188:2199.[Free Full Text]
  7. Suhrbier, A.. 1997. Multi-epitope DNA vaccines. Immunol. Cell Biol. 75:402.[Medline]
  8. Cardin, R. D., J. W. Brooks, S. R. Sarawar, P. C. Doherty. 1996. Progressive loss of CD8+ T cell-mediated control of a {gamma}-herpesvirus in the absence of CD4+ T cells. J. Exp. Med. 184:863.[Abstract/Free Full Text]
  9. Stevenson, P. G., G. T. Belz, J. D. Altman, P. C. Doherty. 1998. Virus-specific CD8+ T cell numbers are maintained during {gamma}-herpesvirus reactivation in CD4-deficient mice. Proc. Natl. Acad. Sci. USA 95:15565.[Abstract/Free Full Text]
  10. Grusby, M. J., R. S. Johnson, V. E. Papaioannou, L. H. Glimcher. 1991. Depletion of CD4+ T cells in major histocompatibility complex class II-deficient mice. Science 253:1417.[Abstract/Free Full Text]
  11. Efstathiou, S., Y. M. Ho, S. Hall, C. J. Styles, S. D. Scott, U. A. Gompels. 1990. Murine herpesvirus 68 is genetically related to the {gamma}herpesviruses Epstein-Barr virus and Herpesvirus saimiri. J . Gen. Virol. 71:1365.[Abstract/Free Full Text]
  12. Virgin, H. W., P. Latreille, P. Wamsley, K. Hallsworth, K. E. Weck, A. J. Dal Canto, S. H. Speck. 1997. Complete sequence and genomic analysis of murine {gamma}herpesvirus 68. J. Virol. 71:5894.[Abstract]
  13. Stewart, J. P., E. J. Usherwood, A. Ross, H. Dyson, T. Nash. 1998. Lung epithelial cells are a major site of murine {gamma}herpesvirus persistence. J. Exp. Med. 187:1941.[Abstract/Free Full Text]
  14. Sunil-Chandra, N. P., S. Efstathiou, A. A. Nash. 1992. Murine {gamma}herpesvirus 68 establishes a latent infection in mouse B lymphocytes in vivo. J. Gen. Virol. 73:3275.[Abstract/Free Full Text]
  15. Weck, K. E., S. S. Kim, H. W. I. Virgin, S. H. Speck. 1999. Macrophages are the major reservoir of latent murine {gamma}herpesvirus 68 in peritoneal cells. J. Virol. 73:3273.[Abstract/Free Full Text]
  16. Kitamura, D., J. Roes, R. Kuhn, K. Rajewsky. 1991. A B cell-deficient mouse by targeted disruption of the membrane exon of the immunoglobulin µ chain gene. Nature 350:423.[Medline]
  17. Weck, K. E., S. S. Kim, IV H. W. Virgin, S. H. Speck. 1999. B cells regulate murine {gamma}herpesvirus 68 latency. J. Virol. 73:4651.[Abstract/Free Full Text]
  18. Virgin, H. W., S. H. Speck. 1999. Unraveling immunity to {gamma}-herpesviruses: a new model for understanding the role of immunity in chronic virus infection. Curr. Opin. Immunol. 11:371.[Medline]
  19. Nash, A. A., B. M. Dutia, J. P. Stewart, A. J. Davison. 2001. Natural history of murine {gamma}-herpesvirus infection. Philos. Trans. R. Soc. Lond. B Biol. Sci. 356:569.[Abstract/Free Full Text]
  20. Doherty, P. C., J. P. Christensen, G. T. Belz, P. G. Stevenson, M. Y. Sangster. 2001. Dissecting the host response to a {gamma}-herpesvirus. Philos. Trans. R. Soc. Lond. B Biol. Sci. 356:581.[Abstract/Free Full Text]
  21. Christensen, J. P., R. D. Cardin, K. C. Branum, P. C. Doherty. 1999. CD4+ T cell-mediated control of a {gamma}-herpesvirus in B cell-deficient mice is mediated by IFN-{gamma}. Proc. Natl. Acad. Sci. USA 96:5135.[Abstract/Free Full Text]
  22. Stevenson, P. G., G. T. Belz, J. D. Altman, P. C. Doherty. 1999. Changing patterns of dominance in the CD8+ T cell response during acute and persistent murine {gamma}-herpesvirus infection. Eur. J. Immunol. 29:1059.[Medline]
  23. Belz, G. T., P. G. Stevenson, M. R. Castrucci, J. D. Altman, P. C. Doherty. 2000. Postexposure vaccination massively increases the prevalence of {gamma}-herpesvirus-specific CD8+ T cells but confers minimal survival advantage on CD4-deficient mice. Proc. Natl. Acad. Sci. USA 97:2725.[Abstract/Free Full Text]
  24. Stevenson, P. G., G. T. Belz, M. R. Castrucci, J. D. Altman, P. C. Doherty. 1999. A {gamma}-herpesvirus sneaks through a CD8+ T cell response primed to a lytic-phase epitope. Proc. Natl. Acad. Sci. USA 96:928.
  25. Battegay, M., D. Moskophidis, A. Rahemtulla, H. Hengartner, T. W. Mak, R. M. Zinkernagel. 1994. Enhanced establishment of a virus carrier state in adult CD4+ T-cell-deficient mice. J. Virol. 68:4700.[Abstract/Free Full Text]
  26. Matloubian, M., R. J. Concepcion, R. Ahmed. 1994. CD4+ T cells are required to sustain CD8+ cytotoxic T-cell responses during chronic viral infection. J. Virol. 68:8056.[Abstract/Free Full Text]
  27. Zajac, A. J., J. N. Blattman, K. Murali-Krishna, D. J. Sourdive, M. Suresh, J. D. Altman, R. Ahmed. 1998. Viral immune evasion due to persistence of activated T cells without effector function. J. Exp. Med. 188:2205.[Abstract/Free Full Text]
  28. Marshall, D. R., S. J. Turner, G. T. Belz, S. Wingo, S. Andreansky, M. Y. Sangster, J. M. Riberdy, T. Liu, M. Tan, P. C. Doherty. 2001. Measuring the diaspora for virus-specific CD8+ T cells. Proc. Natl. Acad. Sci. USA 98:6313.[Abstract/Free Full Text]
  29. Springer, T. A.. 1990. Adhesion receptors of the immune system. Nature 346:425.[Medline]
  30. Taylor-Fishwick, D. A., J. N. Siegel. 1995. Raf-1 provides a dominant but not exclusive signal for the induction of CD69 expression on T cells. Eur. J. Immunol. 25:3215.[Medline]
  31. Stevenson, P. G., P. C. Doherty. 1998. Kinetic analysis of the specific host response to a murine {gamma}herpesvirus. J. Virol. 72:943.[Abstract/Free Full Text]
  32. Slifka, M. K., J. L. Whitton. 2000. Activated and memory CD8+ T cells can be distinguished by their cytokine profiles and phenotypic markers. J. Immunol. 164:208.[Abstract/Free Full Text]
  33. Belz, G. T., W. Xie, P. C. Doherty. 2001. Diversity of epitope and cytokine profiles for primary and secondary influenza a virus-specific CD8+ T cell responses. J. Immunol. 166:4627.[Abstract/Free Full Text]
  34. Schooley, R. T., C. Spino, D. Kuritzkes, B. D. Walker, F. A. Valentine, M. S. Hirsch, E. Cooney, G. Friedland, S. Kundu, T. C. Merigan, et al 2000. Two double-blinded, randomized, comparative trials of 4 human immunodeficiency virus type 1 (HIV-1) envelope vaccines in HIV-1- infected individuals across a spectrum of disease severity: AIDS clinical trials groups 209 and 214. J. Infect. Dis. 182:1357.[Medline]
  35. Sherritt, M. A., J. Gardner, S. L. Elliott, C. Schmidt, D. Purdie, G. Deliyannis, W. R. Heath, A. Suhrbier. 2000. Effect of pre-existing cytotoxic T lymphocytes on therapeutic vaccines. Eur. J. Immunol. 30:671.[Medline]
  36. Banchereau, J., B. Schuler-Thurner, A. K. Palucka, G. Schuler. 2001. Dendritic cells as vectors for therapy. Cell 106:271.[Medline]
  37. Kalams, S. A., S. P. Buchbinder, E. S. Rosenberg, J. M. Billingsley, D. S. Colbert, N. G. Jones, A. K. Shea, A. K. Trocha, B. D. Walker. 1999. Association between virus-specific cytotoxic T-lymphocyte and helper responses in human immunodeficiency virus type 1 infection. J. Virol. 73:6715.[Abstract/Free Full Text]
  38. Ridge, J. P., F. Di Rosa, P. Matzinger. 1998. A conditioned dendritic cell can be a temporal bridge between a CD4+ T-helper and a T-killer cell. Nature 393:474.[Medline]
  39. Bennett, S. R., F. R. Carbone, F. Karamalis, R. A. Flavell, J. F. Miller, W. R. Heath. 1998. Help for cytotoxic-T-cell responses is mediated by CD40 signalling. Nature 393:478.[Medline]
  40. Topham, D. J., R. C. Cardin, J. P. Christensen, J. W. Brooks, G. T. Belz, P. C. Doherty. 2001. Perforin and Fas in murine {gamma}herpesvirus-specific CD8+ T cell control and morbidity. J. Gen. Virol. 82:1971.[Abstract/Free Full Text]
  41. Stevenson, P. G., S. Efstathiou, P. C. Doherty, P. J. Lehner. 2000. Inhibition of MHC class I-restricted antigen presentation by {gamma}2-herpesviruses. Proc. Natl. Acad. Sci. USA 97:8455.[Abstract/Free Full Text]
  42. Ceredig, R., J. E. Allan, Z. Tabi, F. Lynch, P. C. Doherty. 1987. Phenotypic analysis of the inflammatory exudate in murine lymphocytic choriomeningitis. J. Exp. Med. 165:1539.[Abstract/Free Full Text]
  43. Budd, R. C., J. C. Cerottini, H. R. MacDonald. 1987. Phenotypic identification of memory cytolytic T lymphocytes in a subset of Lyt-2+ cells. J. Immunol. 138:1009.[Abstract/Free Full Text]
  44. Tabi, Z., F. Lynch, R. Ceredig, J. E. Allan, P. C. Doherty. 1988. Virus-specific memory T cells are Pgp-1+ and can be selectively activated with phorbol ester and calcium ionophore. Cell Immunol. 113:268.[Medline]
  45. Dianzani, U., M. Bragardo, A. Tosti, L. Ruggeri, I. Volpi, M. Casucci, F. Bottarel, M. J. Feito, S. Bonissoni, A. Velardi. 1999. CD44 signaling through p56lck involves lateral association with CD4 in human CD4+ T cells. Int. Immunol. 11:1085.[Abstract/Free Full Text]
  46. Foger, N., R. Marhaba, M. Zoller. 2000. CD44 supports T cell proliferation and apoptosis by apposition of protein kinases. Eur. J. Immunol. 30:2888.[Medline]
  47. Foger, N., R. Marhaba, M. Zoller. 2001. Involvement of CD44 in cytoskeleton rearrangement and raft reorganization in T cells. J. Cell Sci. 114:1169.[Abstract]
  48. Goulder, P. J., Y. Tang, C. Brander, M. R. Betts, M. Altfeld, K. Annamalai, A. Trocha, S. He, E. S. Rosenberg, G. Ogg, et al 2000. Functionally inert HIV-specific cytotoxic T lymphocytes do not play a major role in chronically infected adults and children. J. Exp. Med. 192:1819.[Abstract/Free Full Text]
  49. Liebeman, J., P. Shankar, N. Manjunath, J. Andersson. 2001. Dressed to kill: a review of why antiviral CD8 T lymphocytes fail to prevent progressive immunodeficiency in HIV-1 infection. Blood 98:1667.[Abstract/Free Full Text]
  50. Trimble, L. A., J. Lieberman. 1998. Circulating CD8 T lymphocytes in human immunodeficiency virus-infected individuals have impaired function and downmodulate CD3{zeta}, the signaling chain of the T-cell receptor complex. Blood 91:585.[Abstract/Free Full Text]
  51. Shankar, P., Z. Xu, J. Lieberman. 1999. Viral-specific cytotoxic T lymphocytes lyse human immunodeficiency virus-infected primary T lymphocytes by the granule exocytosis pathway. Blood 94:3084.[Abstract/Free Full Text]
  52. Chen, G., P. Shankar, C. Lange, H. Valdez, P. R. Skolnik, L. Wu, N. Manjunath, J. Lieberman. 2001. CD8 T cells specific for human immunodeficiency virus, Epstein-Barr virus, and cytomegalovirus lack molecules for homing to lymphoid sites of infection. Blood 98:156.[Abstract/Free Full Text]
  53. Jr Gale, M. J., L. A. Ledbetter, G. L. Schieven, M. Jonker, W. R. Morton, R. E. Benveniste, E. A. Clark. 1990. CD4 and CD8 T cells from SIV-infected macaques have defective signaling responses after perturbation of either CD3 or CD2 receptors. Int. Immunol. 2:849.[Abstract/Free Full Text]
  54. Gruener, N. H., F. Lechner, M. C. Jung, H. Diepolder, T. Gerlach, G. Lauer, B. Walker, J. Sullivan, R. Phillips, G. R. Pape, P. Klenerman. 2001. Sustained dysfunction of antiviral CD8+ T lymphocytes after infection with hepatitis C virus. J. Virol. 75:5550.[Abstract/Free Full Text]
  55. Doherty, P. C., R. M. Zinkernagel. 1974. T-cell-mediated immunopathology in viral infections. Transplant. Rev. 19:89.[Medline]
  56. Zinkernagel, R. M., E. Haenseler, T. Leist, A. Cerny, H. Hengartner, A. Althage. 1986. T cell-mediated hepatitis in mice infected with lymphocytic choriomeningitis virus: liver cell destruction by H-2 class I-restricted virus-specific cytotoxic T cells as a physiological correlate of the 51Cr-release assay?. J. Exp. Med. 164:1075.[Abstract/Free Full Text]
  57. Belz, G. T., P. C. Doherty. 2001. Virus-specific and bystander CD8+ T-cell proliferation in the acute and persistent phases of a {gamma}herpesvirus infection. J. Virol. 75:4435.[Abstract/Free Full Text]
  58. Flano, E., D. L. Woodland, M. A. Blackman, P. C. Doherty. 2001. Analysis of virus-specific CD4+ t cells during long-term {gamma}herpesvirus infection. J. Virol. 75:7744.[Abstract/Free Full Text]
  59. Flano, E., S. M. Husain, J. T. Sample, D. L. Woodland, M. A. Blackman. 2000. Latent murine {gamma}-herpesvirus infection is established in activated B cells, dendritic cells, and macrophages. J. Immunol. 165:1074.[Abstract/Free Full Text]



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