By
From the Section of Infectious Diseases and the Section of Immunobiology, Yale University School of Medicine, New Haven, Connecticut 06520
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Abstract |
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The mechanisms underlying the genesis and maintenance of T cell memory remain unclear. In
this study, we examined the evolution of a complex, antigen-specific T cell population during
the transition from primary effector to memory T cells after Listeria monocytogenes infection. T
cell populations specific for listeriolysin O (LLO)91-99, the immunodominant epitope recognized by H2-Kd-restricted T lymphocytes, were directly identified in immune spleens using
tetrameric H2-Kd-epitope complexes. The T cell receptor (TCR) V repertoire of specific T
cells was determined by direct, ex vivo staining with a panel of mAbs. We demonstrate that
LLO91-99-specific, primary effector T cell populations have a diverse TCR V
repertoire. Analyses of memory T cell populations demonstrated similar TCR diversity. Furthermore, experiments with individual mice demonstrated that primary effector and memory T cells have
indistinguishable TCR repertoires. Remarkably, after reinfection with L. monocytogenes, LLO91-99-specific T cells have a narrower TCR repertoire than do primary effector or memory
T cells. Thus, our studies show that the TCR repertoire of primary effector T lymphocytes is
uniformly transmitted to memory T cells, whereas expansion of memory T cells is selective.
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Introduction |
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The adaptive immune response to infectious agents is characterized by initial priming and expansion of complex, pathogen-specific T cell populations. The elicited effector T cells participate in the host defense by controlling the infection and eradicating the pathogen. Interestingly, the in vivo dynamics of antigen-specific T cell responses during the course of infection are very similar, even when the pathogens are very different: initial expansion of effector T cells is followed by a rapid contraction phase, leaving a relatively stable pool of memory T cells that provide long-term immunity (1, 2). The mechanisms that determine and regulate this transition from effector to memory T cells are not known. How are memory T cells generated and maintained? When do memory T cells become distinct from effector T cells? Are there qualitative differences between these two populations that might be reflected by differences in their TCR repertoire? These questions are fundamental to our understanding of protective immunity and have important implications for vaccine design and development.
The differences between naive, unprimed T cells and memory T cell populations are dramatic. Memory T cells require less antigen, do not require costimulation for activation, and expand more rapidly than naive T cells (3, 4). Additional phenotypic differences, such as higher surface expression of adhesion molecules, have also been described (2, 5). However, the distinction between effector T cells and memory T cells is less clear. Thus, it is still unknown whether memory T cells are a distinct cell lineage generated during antigen challenge, or if they are directly selected from activated effector T cells (1). If there is selection of memory T cells, the avidity of the TCR-MHC-peptide interaction might be of special importance. Consistent with this notion, recent studies showed that maintenance of naive or memory T cells had distinct requirements, but both required the presence of MHC molecules in the periphery (8).
One approach to determine the differences or similarities
between effector and memory T cell populations is to characterize and compare their TCR repertoire. Because of the
difficulties identifying small numbers of epitope-specific
T cells among much larger populations of nonspecific cells,
most of our knowledge of TCR repertoire evolution after
immunization comes from systems where a highly restricted T cell population responds to a dominant T cell
epitope (6, 9). In these systems, the predominance of a
particular TCR V segment was used to detect antigen-specific T cells for further analyses of TCR V
chains and
CDR3 sequences. These experiments demonstrated very
similar TCR repertoires in effector and memory T cell
populations, although in one system some selection for certain CDR3 regions was described (9). However, most effector
T cell responses during infectious diseases are highly diverse
(13), and it remains unknown whether memory T cell
populations maintain this level of TCR repertoire diversity. We have used murine infection with Listeria monocytogenes
to study complex T cell responses to infection. Intravenous
infection of mice with a sublethal dose of L. monocytogenes
causes rapid clearance of the pathogen and the development
of very effective, long lasting immunity, which is mainly
mediated by MHC class I-restricted CTLs (17, 18). Unlike
many viral infections, which cause prolonged or chronic
infections, L. monocytogenes is cleared from infected mice
(19, 20). Four different Listeria epitopes are presented to
CD8+ T lymphocytes by the MHC class I molecule H2-Kd
and the in vivo kinetics of T cells responding to these epitopes have been determined (21). The H2-Kd-restricted immunodominant epitope listeriolysin O (LLO)91-991 induces
the largest number of CTLs (22). Interestingly, in vitro-
expanded, LLO91-99-specific T cells express a highly diverse
TCR V
repertoire (25).
In this study we have used tetrameric H2-Kd-LLO91-99
complexes to characterize the TCR V repertoire of specific
effector, memory, and recall T cells after L. monocytogenes
infection. Primary effector T lymphocytes specific for the
Listeria epitope LLO91-99 are characterized by a diverse TCR
V
repertoire. This diversity is maintained in memory T
cell populations. Remarkably, rechallenge with L. monocytogenes induces changes in the epitope-specific TCR repertoire, with focus on a narrower range of TCR V
segments. These findings suggest that the breadth of the primary effector TCR repertoire is transmitted to and maintained in
the memory compartment. However, expansion of the
memory T cell pool narrows the repertoire of recall effector T cells. We propose that contracting or static T cell
populations after primary infection maintain TCR diversity, whereas rapidly expanding T cells lose diversity.
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Materials and Methods |
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Mice and Bacteria.
BALB/c mice were obtained from The Jackson Laboratory (Bar Harbor, ME). L. monocytogenes strain 10403s was obtained from Daniel Portnoy (University of California Berkeley, Berkeley, CA) and grown in brain-heart infusion broth.Immunization with Listeria and Harvesting of Spleen Cells.
Mice were immunized by intravenous injection of 2 × 103 L. monocytogenes 10403s into the tail vein. Spleens were removed 7 d after immunization and splenocytes were harvested by dissociation through a wire mesh and lysis of erythrocytes with ammonium chloride, and subsequently resuspended in RP10+, which consists of RPMI 1640 (GIBCO BRL, Gaithersburg, MD) supplemented with 10% FCS, L-glutamine, Hepes (pH 7.5),Enrichment for CD8+ T Cells.
Splenocytes were enriched for CD8+ T cells by positive separation using the magnetically activated cell separation system (MACS; Miltenyi, Bergisch Gladbach, Germany). Splenocytes were incubated with anti-mouse CD8Tetrameric H2-Kd-Peptide Complexes.
MHC-peptide tetramers for staining of epitope-specific T cells were generated as recently described (24, 26). In brief, a specific biotinylation site (27) was added to the COOH terminus of truncated H2-Kd heavy chain (no transmembrane region, truncation after the amino acid in position 284). This fusion protein andIn vitro Peptide Restimulation of LLO91-99-specific T Cell Lines.
T cell lines were established by in vitro peptide restimulation as recently described (25). In brief, 3-4 × 107 spleen cells from immunized mice were incubated in the presence of 3 × 107 irradiated, syngeneic spleen cells that were peptide pulsed for 1 h at 37°C with 10Staining and Flow Cytometry Analysis.
For flow cytometry analysis, ~3 × 105 cells were added per staining to a well of a 96-well plate. After incubation at 4°C for 20 min with unconjugated streptavidin (0.5 mg/ml, Molecular Probes) and Fc-block (PharMingen, San Diego, CA) in FACS® staining buffer (SB; PBS, pH 7.45, 0.5% BSA, and 0.02% sodium azide), cells were triple stained with Cy-Chrome-conjugated anti-CD8 ![]() |
Results |
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The interaction
of T cell receptors with their cognate MHC-peptide complexes is characterized by relatively low affinity and a high
dissociation rate. Therefore, it has not been possible to
use monomeric MHC-peptide complexes to identify antigen-specific T cells. However, a recently described approach
using tetrameric MHC class I-peptide complexes (26) increases the affinity sufficiently to allow cell staining. We
therefore generated tetrameric H2-Kd complexes stabilized
with the immunodominant Listeria epitope LLO91-99.
Truncated H2-Kd heavy chain (no transmembrane region)
containing a genetically engineered biotinylation site at the
COOH terminus (Fig. 1 A), and 2m were expressed as
recombinant proteins in E. coli, and were refolded in the
presence of high concentrations of LLO91-99 peptide. Monomeric H2-Kd-peptide complexes were purified by gel
filtration (Fig. 1 B) and subsequently enzymatically biotinylated with BirA. H2-Kd-peptide complexes could be immunoprecipitated with the conformation-dependent, H2-Kd-
specific mAb SF1-1.1.1 (Fig. 1 C), indicating that complexes were properly refolded, and precipitation experiments with
streptavidin agarose beads demonstrated essentially complete biotinylation after treatment with BirA (Fig. 1 C).
Since streptavidin has four binding sites for biotin, incubation of the biotinylated complexes in the presence of
streptavidin at a molar ratio of 4:1 results in formation of
MHC-peptide tetramers (Fig. 1 D). Streptavidin conjugated with PE was used for flow cytometric detection of
LLO91-99-specific T lymphocytes.
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We have recently shown
that tetrameric H2-Kd-peptide complexes specifically detect Listeria epitope-specific T cells in vitro and ex vivo
(24). LLO91-99 is an immunodominant epitope inducing
relatively high numbers of specific T cells during the course
of infection with L. monocytogenes, which can be easily detected by tetramer staining as primary effector T lymphocytes, as well as after establishment of a memory T cell pool
(24). LLO91-99 tetramers stain essentially all antigen-specific lymphocytes within the complex T cell population (24).
Analysis of in vitro expanded LLO91-99-specific T cell lines
revealed a diverse TCR V repertoire (25). To examine
whether the TCR V
repertoire of LLO91-99-specific T cell
populations can be directly determined by costaining T cells
with tetramers and TCR V
-specific mAbs, we compared
TCR V
staining of in vitro expanded LLO91-99-specific
T cell lines in the presence and absence of LLO91-99-H2-Kd
tetramers. First, a T cell line specific for LLO91-99 was generated from an L. monocytogenes-immunized mouse by in
vitro peptide restimulation (Fig. 2 A). Essentially all CD8+
lymphoblasts in the cell culture are stained by LLO91-99 tetramers (Fig. 2 B). Staining with a panel of different TCR
V
-specific mAbs demonstrated a diverse TCR V
profile, which is identical to that obtained when cells were
double stained with LLO91-99 tetramers (Fig. 2 C, gated on
CD8+, tetramer-positive lymphoblasts). This experiment
indicates that double staining with these TCR V
mAbs
does not interfere with the LLO91-99 tetramer staining.
Similar results were obtained for other LLO91-99-specific T
cell lines (data not shown).
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Next, we examined whether double staining with TCR
V mAbs and LLO91-99 tetramers would allow direct ex
vivo TCR repertoire analyses. BALB/c mice were immunized with a sublethal dose of L. monocytogenes, and spleen
cells were harvested and enriched for CD8+ T cells 7 d later.
As shown in Fig. 3, LLO91-99 tetramers stain a distinct population of CD8+ T cells. Double staining with a TCR-
/
-
specific mAb demonstrates high level TCR-
/
surface
expression on all tetramer-positive T cells (Fig. 3 A). Double staining with the anti-TCR V
8.1-3 mAb F21.3
identifies a distinct subpopulation within the LLO91-99-specific T cell population expressing this particular TCR V
segment (Fig. 3 B).
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We performed direct ex vivo analyses of LLO91-99-specific, primary effector T cells using 14 different TCR V-specific mAbs, which usually cover >90% of all T cells
within this population. Representative histograms of TCR
V
stainings of CD8+/ LLO91-99 tetramer-positive T cells
are shown in Fig. 4. In almost all mice analyzed, substantial
subpopulations within the LLO91-99-specific T cell population could be identified for the TCR V
segments V
2, 4, 5, 8.1/2, 8.1-3, and 10, whereas for other TCR V
segments (V
6, 7, 9, 11, or 14) larger subpopulations could
only be identified in some individual mice (see also Figs. 6
and 7).
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The relatively high and reproducible frequencies of T cells
specific for the immunodominant Listeria epitope LLO91-99 (day 7 primary responders: 1.2-1.5%; 5-wk memory cells:
0.4-0.6% within CD8+ splenocytes) allowed us to determine TCR V profiles using all 14 different TCR V
mAbs among immune splenocytes. In Fig. 5, TCR V
profiles of LLO91-99-specific T cell populations are shown for six
individual mice, three analyzed at the peak of the primary
response and three analyzed 5 wk after primary infection
with L. monocytogenes (memory phase). Primary LLO91-99-specific effector T cell populations show TCR V
diversity, similar to the results obtained with in vitro expanded
T cell lines (25, Fig. 2). The predominant V
segments that
are used are V
2, 4, 8, and 10, whereas other segments are
represented at relatively low frequencies. However, there is
some variability in the TCR V
profiles between individual mice. In the memory pool, LLO91-99-specific T cell
populations are also characterized by diverse TCR V
repertoires, overall showing an extent of diversity similar to
that of primary effector T cell populations. However, there
is variability between individual mice, making it difficult to
determine if the TCR repertoire of LLO91-99-specific
memory T cells directly reflects the repertoire of primary
effector T cells.
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Direct ex vivo staining with MHC-peptide tetramers allowed us to compare the TCR V profiles of an epitope-specific T cell population with the overall TCR V
usage
by CD8+ T cells in the same mouse (Fig. 5, black bars). The
overall TCR V
repertoire of CD8+ T cells in the individual mice tested are remarkably similar, suggesting that intermouse variability in LLO91-99-specific TCRs cannot be
attributed to general differences in the frequencies of different TCR V
populations. TCR V
stainings of naive,
BALB/c splenocytes demonstrated very similar overall
TCR V
repertoires (data not shown). Thus, there is no
detectable skewing in the overall TCR V
repertoire during primary responses to L. monocytogenes.
Taken together, our data show that LLO91-99-specific
primary effector and memory T cell populations have diverse TCR V repertoires. The prevalence of TCR V
chains among LLO91-99-specific T cells and the general population of CD8+ T cells is remarkably similar.
As mentioned above, the mouse to mouse
variability in the TCR V profiles does not permit precise
correlations between memory and primary effector TCR
repertoires. To address this issue, we decided to determine
the TCR V
repertoire of LLO91-99-specific effector and
memory T cells in the same mouse. Therefore, we expanded LLO91-99-specific T cell lines from blood samples
taken at day 7 during the primary response by short term in
vitro peptide stimulation. The TCR V
usage of LLO91-99-specific T cell lines was determined by double staining with
LLO91-99 tetramers and TCR V
mAbs, and compared
with the TCR V
profiles of the LLO91-99-specific memory T cell population 5 wk after primary infection in the
spleen of the same mouse. Fig. 6 shows TCR V
profiles
of LLO91-99-specific effector and memory T cell populations determined in individual mice. The TCR V
repertoires determined at the two time points are very similar, if
not identical. In particular, even relatively small T cell subpopulations persist among memory T cells (e.g., V
7, 9 and 10). T cell populations that are distinct for individual
mice, such as the unusual TCR V
profile in mouse 386, with an unusually large TCR V
9+ subpopulation, is
maintained in the memory pool and underlines the importance of performing serial repertoire analyses in individual mice. These data indicate that the TCR repertoire of acute
effector T cells is transmitted to the memory T cell compartment.
We used the same approach to determine the
TCR V repertoire of LLO91-99-specific, primary effector
T cells from peripheral blood samples and compared this to
the repertoire in mice rechallenged with L. monocytogenes.
As shown in Fig. 7, the recall TCR V
repertoires of
LLO91-99-specific T cell populations differ substantially from the repertoires of primary effector T cell populations.
For all four mice, we found a more restricted TCR V
repertoire in the recall population, suggesting a focusing on
certain TCR V
segments. In particular, less prevalent subpopulations decreased in frequency while the frequency of
dominant V
populations generally increased. Although
focusing could be detected in all four mice, specific changes
were not uniform and differed from mouse to mouse. Whereas mice 390, 391, and 392 show focusing mostly onto
the TCR V
8+ subpopulation (in mouse 391, 70% of all recall effector T cells are positive for the anti-TCR V
8 panantibody), in mouse 393, TCR V
2 becomes the predominant subpopulation. Focusing of the recall TCR repertoire
on other TCR V
segments was found for V
10 in mouse
390 and for V
4 in mouse 392. Mouse 390 showed an unusually high TCR V
7 subpopulation in the effector T cell
population. Unlike mouse 386 in Fig. 6, where the "fingerprint" was also found in the memory pool, after reimmunization the TCR V
7 subpopulation in mouse 390 disappeared almost completely. Taken together, the recall TCR
V
profiles appear to be more restricted when compared with the corresponding primary effector T cell repertoires.
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Discussion |
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Our studies comparing the TCR repertoires of effector
and memory T cell populations responding to the immunodominant Listeria epitope LLO91-99 show the following:
(a) the memory TCR V repertoire is similar to the repertoire of primary effector cells; and (b) focusing of the repertoire
on certain TCR V
segments occurs during rechallenge
with the antigen. Furthermore, our studies demonstrate the
use of tetrameric MHC class I-peptide complexes for direct
ex vivo TCR repertoire analyses, and for the first time
show the TCR repertoire evolution of a complex T cell
population responding to bacterial infection.
Previous studies investigating the evolution of TCR repertoires during in vivo T cell responses have resulted in the
following two models. In the first model, memory T cell
receptor repertoires directly reflect those selected during
the primary response, remain stable over time, and are not
influenced by repetitive antigen exposure (11, 12). The
second involves selection for particular T cell receptors
during the transition from effector to memory T cells,
which results in a more restricted memory TCR repertoire (9). Both models are based on findings in experimental systems where T cell responses are directed at single, highly
dominant epitopes, expanding relatively uniform T cell
populations that express a predominant TCR V chain.
With our studies we wanted to investigate whether the diversity of a highly complex effector T cell population responding to an infectious agent is maintained in the memory
pool. Our findings support a third model, which combines
aspects from both of the above-mentioned models (Fig. 8).
Although the TCR repertoire of memory T cells appears
to directly reflect the repertoire selected during the primary
response, the composition of the repertoire can be substantially modified during reexposure with the antigen.
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Although there is some mouse to mouse variability in
the TCR repertoires of T cell populations selected for the
immunodominant Listeria epitope LLO91-99, the TCR profile elicited by primary infection is highly conserved in the
memory T cell population of the same individual mouse. This
is consistent with observations in other experimental systems
(11). In our studies, we determined the TCR V repertoire
of epitope-specific T cell populations, which provides a general picture of the overall diversity of the epitope-specific
response. Although this approach does not determine the
complete diversity of the T cell response, its advantage is that TCR V
staining allows us to characterize the majority
of T cells within the antigen-specific T cell population
(usually >90% of LLO91-99-specific T cell populations are
covered by staining with the 14 different TCR V
mAbs)
directly ex vivo without the need of further in vitro propagation. The validity of this approach is supported by the recent finding that the degree of TCR repertoire diversity of
EBV-specific T cell populations is maintained on the level
of the TCR V
segments, indicating that TCR V
usage
directly correlates with the overall complexity of a given T cell
population (29). The complexity of primary effector T cells
specific for LLO91-99 is precisely maintained in the memory
T cell population. This finding suggests that selection of
memory T cells is either very similar to or completely overlaps the selection of primary effector T cells during priming.
Our results are interesting in the context of recent findings,
which show that the maintenance of memory T cells is far
less dependent on the presence of the restricting MHC
molecule than is the maintenance of naive, unprimed T
cells (8). Thus, individual T cell subpopulations within the
broad repertoire of the T cells specific for LLO91-99, which
may consist of TCRs with different affinities for H2-Kd-
LLO91-99 complexes, are treated equivalently in the memory compartment. However, our experiments do not rule
out the possibility that further maturation and qualitative
changes of memory T cell populations occur very slowly
over prolonged periods of time. Thus, it will be of particular interest to monitor TCR repertoires of complex memory T cell populations over longer periods of time.
The TCR V repertoire of LLO91-99-specific T cells becomes narrower in immune mice after rechallenge with
L. monocytogenes. This observation differs from findings in
other experimental systems, where antigen reexposure had
no influence on the TCR repertoire (11). However, those
experiments were characterized by a highly restricted primary T cell response, a factor that may limit further restriction during a recall response. The basis for repertoire focusing in our system is not known. Although the mice were
rechallenged with a much larger infecting dose of L. monocytogenes (100,000 bacteria for recall infection compared
with 2,000 bacteria for primary infections), bacterial clearance occurs much more rapidly in immune mice than in
naive mice (48-72 h compared with 1 wk). It is possible
that the kinetics of bacterial clearance and, consequently, the differences in the overall antigen quantity may account
for qualitative changes in the expanded T cell population.
Thus, T cell clones that are capable of responding to lower
amounts of epitope, perhaps on the basis of a higher avidity
for the cognate MHC-peptide complexes, might have a selective advantage. However, preliminary experiments analyzing recall TCR repertoires in response to 20-fold lower
infecting doses of L. monocytogenes demonstrated similar expansion of LLO91-99-specific T cells with an identical extent of TCR repertoire focusing (Busch, D.H., and E.G.
Pamer, unpublished data).
Determining the cellular and molecular basis for repertoire focusing after reexposure to antigen will require further investigation. Studies of the relative affinities of more focused T cell populations for their cognate peptide-MHC complex may be particularly informative.
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Footnotes |
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Address correspondence to Eric G. Pamer, Sections of Infectious Diseases and Immunobiology, Yale University, New Haven, CT 06520. Phone: 203-785-3561; Fax: 203-785-3864; E-mail: eric.pamer{at}yale.edu
Received for publication 17 February 1998 and in revised form 8 April 1998.
This work was supported by National Institutes of Health grants AI-33143 and AI-39031. E.G. Pamer is a Pew Scholar in the Biomedical Sciences, and D.H. Busch is a research fellow of the Deutsche Forschungsgemeinschaft (DFG).
Abbreviations used in this paper
2m,
2 microglobulin;
BirA, biotin operon repressor protein A;
LLO, listeriolysin O;
SB, staining buffer.
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References |
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![]() ![]() ![]() ![]() ![]() ![]() ![]() |
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1. | Ahmed, R., and D. Gray. 1996. Immunological memory and protective immunity: understanding their relation. Science. 272: 54-60 [Abstract]. |
2. | Sprent, J.. 1997. Immunological memory. Curr. Opin. Immunol. 9: 371-379 [Medline]. |
3. |
Pihlgren, M.,
P.M. Dubois,
M. Tomkowiak,
T. Sjogren, and
J. Marvel.
1996.
Resting memory CD8+ T cells are hyperreactive to antigenic challenge in vitro.
J. Exp. Med.
184:
2141-2151
|
4. | Bruno, L., J. Kirberg, and H. von Boehmer. 1995. On the cellular basis of immunological memory. Immunity. 2: 37-43 [Medline]. |
5. | Pihlgren, M., L. Lightstone, C. Mamalaki, G. Rimon, and D. Kioussis. 1995. Expression in vivo of CD45RA, CD45RB and CD44 on T cell receptor-transgenic CD8+ T cells following immunization. Eur. J. Immunol. 25: 1755-1759 [Medline]. |
6. | Walker, P.R., T. Ohteki, J.A. Lopez, H.R. MacDonald, and J.L. Maryanski. 1995. Distinct phenotypes of antigen-selected CD8 T cells emerge at different stages of an in vivo immune response. J. Immunol. 155: 3443-3452 [Abstract]. |
7. | Zimmerman, C., K. Brduscha-Riem, C. Blaser, R.M. Zinkernagel, and H. Pircher. 1996. Visualization, characterization, and turnover of CD8+ memory T cells in virus-infected hosts. J. Exp. Med. 183: 1367-1375 [Abstract]. |
8. |
Tanchot, C.,
F.A. Lemonnier,
B. Perarnau,
A.A. Freitas, and
B. Rocha.
1997.
Differential requirements for survival and
proliferation of CD8 naive and memory T cells.
Science.
276:
2057-2062
|
9. | McHeyzer-Williams, M.G., and M.M. Davis. 1995. Antigen-specific development of primary and memory T cells in vivo. Science. 268: 106-111 [Medline]. |
10. | McHeyzer-Williams, M.G., J.D. Altman, and M.M. Davis. 1996. Tracking antigen-specific helper T cell responses. Curr. Opin. Immunol. 8: 278-284 [Medline]. |
11. | Walker, P.R., A. Wilson, P. Bucher, and J.L. Maryanski. 1996. Memory TCR repertoires analyzed long-term reflect those selected during the primary response. Int. Immunol. 3: 1131-1138 . |
12. | Maryanski, J.L., C.V. Jongeneel, P. Bucher, J.L. Casanova, and P.R. Walker. 1996. Single-cell PCR analysis of TCR repertoires selected by antigen in vivo: a high magnitude CD8 response is comprised of very few clones. Immunity. 4: 47-56 [Medline]. |
13. | Casanova, J.L., P. Romero, C. Widmann, P. Kourilsky, and J.L. Maryanski. 1991. T cell receptor genes in a series of class I major histocompatibility complex-restricted cytotoxic T lymphocyte clones specific for a Plasmodium berghei nonapeptide: implications for T cell allelic exclusion and antigen-specific repertoire. J. Exp. Med. 174: 1371-1383 [Abstract]. |
14. | Cole, G.A., T.L. Hogg, and D.L. Woodland. 1994. The MHC class I-restricted T cell response to Sendai virus infection in C57BL/6 mice: a single immunodominant epitope elicits an extremely diverse repertoire of T cells. Int. Immunol. 6: 1767-1775 [Abstract]. |
15. | Horwitz, M.S., Y. Yanagi, and M.B. Oldstone. 1994. T-cell receptors from virus-specific cytotoxic T lymphocytes recognizing a single immunodominant nine-amino-acid viral epitope show marked diversity. J. Virol. 68: 352-357 [Abstract]. |
16. | Cose, S.C., J.M. Kelly, and F.R. Carbone. 1995. Characterization of diverse primary herpes simplex virus type 1 gB-specific cytotoxic T-cell response showing a preferential V beta bias. J. Virol. 69: 5849-5852 [Abstract]. |
17. |
Kaufmann, S.H.E.,
H.R. Rodewald,
E. Hug, and
G.D. Libero.
1988.
Cloned Listeria monocytogenes specific non-MHC-restricted Lyt-2+ T cells with cytolytic and protective
activity.
J. Immunol.
140:
3173-3179
|
18. | Pamer, E.G. 1997. Immune response to Listeria monocytogenes. In Host Response to Intracellular pathogens. S.H.E. Kaufmann, editor. R.G. Landes, Austin, TX. 131-142. |
19. | van der Most, R.G., A. Sette, C. Oseroff, J. Alexander, K. Murali-Krishna, L.L. Lau, S. Southwood, J. Sidney, R.W. Chesnut, M. Matloubian, and R. Ahmed. 1996. Analysis of cytotoxic T cell responses to dominant and subdominant epitopes during acute and chronic lymphocytic choriomeningitis virus infection. J. Immunol. 157: 5543-5554 [Abstract]. |
20. | Steven, N.M., A.M. Leese, N.E. Annels, S.P. Lee, and A.B. Rickinson. 1996. Epitope focusing in the primary cytotoxic T cell response to Epstein-Barr virus and its relationship to T cell memory. J. Exp. Med. 184: 1801-1813 [Abstract]. |
21. | Pamer, E.G., A.J. Sijts, M.S. Villanueva, D.H. Busch, and S. Vijh. 1997. MHC class I antigen processing of Listeria monocytogenes proteins: implications for dominant and subdominant CTL responses. Immunol. Rev. 158: 129-136 [Medline]. |
22. | Vijh, S., and E.G. Pamer. 1997. Immunodominant and subdominant CTL responses to Listeria monocytogenes infection. J. Immunol. 158: 3366-3371 [Abstract]. |
23. | Busch, D.H., H.G.A. Bouwer, D. Hinrichs, and E.G. Pamer. 1997. A nonamer peptide derived from Listeria monocytogenes metalloprotease is presented to cytotoxic T lymphocytes. Infect. Immun. 65: 5326-5329 [Abstract]. |
24. | Busch, D.H., I.M. Pilip, S. Vijh, and E.G. Pamer. 1998. Coordinate regulation of complex T cell populations responding to bacterial infection. Immunity. 8: 353-362 [Medline]. |
25. |
Busch, D.H.,
I.M. Pilip, and
E.G. Pamer.
1998.
MHC class
I/peptide stability: implications for immunodominance, in-vitro proliferation and diversity of responding CTL.
J. Immunol.
160:
4441-4448
|
26. |
Altman, J.D.,
P.A.H. Moss,
P.J.R. Goulder,
D.H. Barouch,
M.G. McHeyzer-Williams,
J.I. Bell,
A.J. McMichael, and
M.M. Davis.
1996.
Phenotypic analysis of antigen specific T
lymphocytes.
Science.
274:
94-96
|
27. | Schatz, P.J.. 1993. Use of peptide libraries to map the substrate specificity of a peptide modifying enzyme: a 13 residue consensus peptide specifies biotinylation in Escherichia coli. Biotechnology. 11: 1138-1143 [Medline]. |
28. |
Garboczi, D.N.,
U. Utz,
P. Ghosh,
A. Seth,
J. Kim,
E.A. VanTienhoven,
W.E. Biddison, and
D.C. Wiley.
1996.
Assembly, specific binding, and crystallization of a human
TCR-![]() ![]() |
29. |
de Campos-Lima, P.O.,
V. Levitsky,
M.P. Imreh,
R. Gavioli, and
M.G. Masucci.
1997.
Epitope-dependent selection of
highly restricted or diverse T cell receptor repertoires in response to persistent infection by Epstein-Barr virus.
J. Exp.
Med.
186:
83-89
|