| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Interact Differently with 
2-Microglobulin of the Class I Molecules H-2Kb and Thymic Leukemia Antigen, While Similarly with Their 3 Domains1
* Department of Laboratory Medicine and Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520; and
Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
homodimers with
a 10-fold higher affinity than H-2Kb class I molecules. To
understand the molecular basis for this difference, we created a panel
of CD8 mutants and tested the ability of the CD8 homodimers to
bind to H-2Kb tetramers and TL tetramers. Mutations in
three CD8 residues located on the complementarity-determining
region-like loops contacting the negatively charged loop in the 3
domain of MHC class I greatly reduced binding to both tetramers.
Because TL and H-2Kb class I sequences are highly conserved
in the 3 domain of MHC class I, this suggests that CD8 contacts the
3 domain of TL and H-2Kb in a similar manner. In
contrast, mutations in residues on the A and B 
strands of CD8 that
are involved in contact with 2-microglobulin affected
interaction with the H-2Kb tetramer, but not the TL
tetramer. Therefore, the orientation of interaction of TL with CD8
appears to be different from that of H-2Kb. The unique high
affinity binding of TL with CD8 is most likely a result of amino
acid differences in the 3 domain between TL and
H-2Kb, particularly at positions 198 (K to D) and
228 (M to T), which are contact residues in the
CD8-H-2Kb cocrystal. |
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
) or a heterodimer (CD8), and in humans can also be
expressed as a CD8 homodimer on transfectants or transgenic
animals (1). CD8 signals inside the cell through its
association with the tyrosine kinase p56lck
(2, 3) and linker of activation in T cells
(4). The -chain facilitates interaction with rafts via
palmitoylation of its cytoplasmic domain (5). CD8 also has
a number of other ligands, including T lymphocyte-triggering factor
(6), gp180 (7), and nonclassical class I MHC
molecules (class Ib) such as HLA-G (8) and murine thymic
leukemia Ag (TL)4
(9).
Mutational analyses (10, 11, 12, 13, 14) and x-ray crystallography
(15, 16) of the CD8-MHC class I interaction show
that the complementarity-determining region (CDR) loops on CD8
make contact with a negatively charged loop on the 3 domain
of MHC class I, and that CD8 residues on the A and B -strands of one
of the Ig domains (1 subunit) interact with residues of
2-microglobulin (2m)
and the 2 domain of MHC class I. Although the major contact is with
the 3 domain of MHC class I, the interaction is different between
murine and human CD8 and MHC class I. Human CD8 has more contacts with
the 2 domain of MHC class I and does not contact the AB loop at the
base of the 3 domain. Furthermore, murine CD8 has four residues at
the N terminus that make additional contacts with
2m. Currently, it is not known whether CD8
interacts with other ligands in a similar manner.
Class Ib MHC molecules are similar in structure to the
classical class I molecules; they have 1, 2, and 3 domains
with varying homology to MHC class I and are associated with
2m. This study focuses on a comparison of CD8
interaction with the class Ib MHC molecule TL and the classical MHC
class I molecule H-2Kb using tetramers of both
molecules. TL has a unique pattern of expression. It is most abundantly
expressed on the intestinal epithelial cells in all mouse strains
(17). It has an overall homology to MHC class I of 70%,
with the greatest homology (86%) being in the 3 domain that
contains the CD8-binding motif (18). Of the 21 aa in the
3 domain of H-2Kb shown to contact CD8 in the
cocrystal (16), TL only varies from
H-2Kb at two positions (198 and 228). In
addition, TL has been shown to bind to both murine and human CD8
(9).
In contrast to the interaction of CD8 with classical MHC
class I molecules, TL was recently shown to bind preferentially to
murine CD8 homodimers in comparison with CD8 heterodimers
(19). In addition, the affinity for the interaction with
CD8 was 10-fold greater than that of classical MHC class I
(19). TL tetramers have been shown to bind to a
TL-specific CTL line via a TCR/CD3-dependent mechanism
(20), and to intraepithelial lymphocytes and thymocytes
via a CD8-dependent/CD3-independent interaction (19).
In this study, we confirm that CD8 alone is sufficient to bind TL
tetramers and compare the ability of H-2Kb and TL
tetramers to bind to CD8 with mutations of solvent-exposed residues.
Our mutational analysis demonstrates that both
H-2Kb and TL make contact with CD8 residues
located on the CDR-like loops that contact the negatively charged loop
in the 3 domain of MHC class I. An anti-CD8 Ab recognizing an
epitope on the 3 domain contact region also blocked the interaction
of both proteins. However, mutations in residues located on the side of
CD8 (A and B strands) involved in contact with
2m had a major effect on binding of the
H-2Kb tetramer, but not the TL tetramer. Based on
these results, we suggest that the main contact between CD8 and
TL is with the 3 domain of TL and the face of CD8 containing the
CDR-like loops. However, the orientation is different so that CD8 has
either no or little contact with 2m.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Mutagenesis of solvent-exposed residues on mouse CD8 (Lyt-2)
was performed using the GeneEditor Mutagenesis kit (Promega, Madison,
WI). Oligonucleotides were designed to change the designated amino acid
and to create a restriction site to identify mutants (Table I
). Mutagenesis was conducted in the
expression vector (pCDL-SR296), and each construct was sequenced to
confirm the presence of the mutation.
|
CD8 expression on COS-7 cells
COS-7 fibroblasts were cultured and maintained in RPMI 1640 with
10% FBS (HyClone, Logan, UT). Eighteen to 24 h before
transfection, cells were plated out at 2 x
105 cells per 60-mm plate. Liposome-mediated
transfection was performed, as previously described (13).
For expression of the CD8 homodimer, 4 µg of wild-type (WT) or
mutant CD8 cDNA in 200 µl of Optimem was added to 200 µl of
Optimem plus 16 µl of Lipofectamine (both Life Technologies, Grand
Island, NY). For experiments requiring expression of the CD8
heterodimer, 2 µg of CD8 and 2 µg of CD8 cDNA were used for
the transfection mix. Reagent mixtures were kept in the dark at room
temperature for 30 min, after which 2 ml of Optimem was added to each
tube, followed by plating onto the COS-7 cells. After 5 h, the
reagent mix was removed, and 4 ml of culture medium was added to each
plate. Cells were given fresh media every 24 h and harvested for
phenotypic analysis at 48 or 72 h.
Preparation of tetramers
OVAp or SIYp H-2Kb tetramers were prepared
with peptides SIINFEKL or SIYRYYGL, respectively, using the previously
described method (21). Briefly, human
2m and a truncated form of
H-2Kb H chain, in which the transmembrane and
cytosolic domain had been removed and a specific biotinylation site
added to the C terminus (22), were expressed in
Escherichia coli strain BL21 (DE3) LysS. Inclusion bodies
were purified and the proteins were refolded, as described previously
(23). Refolding was performed at 10°C in the presence of
25 µg/ml peptide (Research Genetics, Huntsville, AL) and protease
inhibitors: pepstatin A (1 µg/ml), leupeptin (1 µg/ml), and PMSF
(0.4 mM). Soluble monomeric complexes were purified by gel filtration
over a Superdex 200HR column (Amersham Pharmacia Biotech, Piscataway,
NJ) and enzymatically biotinylated by overnight incubation with
purified biotin protein ligase (BirA) at room temperature with
components, as follows: 5 µM HLA-A2/peptide, BirA enzyme (1.5 x
106 U; Avidity, Denver, CO), 80 µM biotin, 10
mM ATP, 10 mM MgOAc, and 20 mM bicine. Unbound biotin was removed by
gel filtration, and the purified monomers were tetramerized by
incubation with PE-labeled streptavidin (Molecular Probes, Eugene, OR)
at a molar ratio of 4:1.
TL tetramers were prepared as described previously
(19). Basically, the extracellular domain of TL
terminating at the tryptophan residue at the end of the 3 domain was
linked to a BirA tag-coding sequence. This was expressed in baculovirus
with murine 2m. The protein was biotinylated,
and tetramers were made with streptavidin-PE (BD PharMingen, San
Diego, CA).
FACS analysis of CD8 expression and tetramer binding
CD8 expression was determined by staining with mAbs
CT-CD8-FITC (Caltag Laboratories, Burlingame, CA) and 53.6.7-FITC
(BD PharMingen) before tetramer-binding assays. In addition, CD8
expression was confirmed by staining with CT-CD8-PE (Caltag
Laboratories). For analysis of MHC tetramer binding, 1 µl of
H-2Kb tetramer or 0.5 µl of TL tetramer was
added to a minimum of 105 cells and incubated for
1 h at 4°C on a rocker platform. Following incubation, cells
were washed twice in buffer (PBS with 1% FCS and 0.1 mM sodium azide),
then analyzed on a FACScan or FACSCalibur flow cytometer. For Ab
inhibition experiments, 10 µl of unconjugated 53.6.7 (or 4 µg of
purified Ab), H59 supernatant (S. Jameson, University of Minnesota
Medical School, Minneapolis, MN), or 6 µg of CT-CD8 was
added to cells for 30 min, washed once, then assayed for tetramer
binding, as described.
Results were calculated using both the percentage of positive cells and the mean fluorescence of the positive population relative to the expression level, using the following formulas: (mean fluorescence intensity tetramer)/(mean fluorescence intensity Ab) x (% positive tetramer - vector)/(% positive Ab - vector) = binding index (BI).
The BI of tetramer binding to CD8 WT was taken as 100%, and results
were expressed relative to WT: (BI mutant)/(BI WT) x 100 =
% binding relative to WT.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The ability of H-2Kb and TL tetramers
(T18d allele) to bind to COS-7
transfectants expressing either CD8 alone or CD8 and was
compared. The best binding was observed with the TL tetramer binding to
CD8 homodimers, with the histogram profile being similar to that
of anti-CD8 Ab staining (Fig. 1).
In this experiment, the mean fluorescence intensity of the positive
population was 1013 for TL binding to CD8 compared with 633 for
H2-Kb tetramers binding to the same cells.
Additional comparisons of TL and H2-Kb tetramers
binding to WT CD8 and CD8 can be seen in Figs. 6 and 7. The
H-2Kb tetramers bound to both CD8 and
CD8 transfectants, but the binding was never as good as the
binding of TL, consistent with previous findings on the much higher
affinity of TL for CD8.
|
|
|
The ability of Abs against both CD8 and CD8 to block the
interaction of tetramers was examined. The two anti-CD8 Abs
CT-CD8a and H59.101 bind to regions of CD8 that are involved in contact
with MHC class I (3 domain or 2m,
respectively, unpublished epitope-mapping data). They blocked both
H-2Kb (Fig. 2A) and TL tetramer binding
(Fig. 2B) to COS-7 cells expressing either CD8 alone or
CD8 and . The anti-CD8-specific Ab, H35.17, only reduced
the binding of H-2Kb tetramers, not
TLtetramers, to cells transfected with CD8 and CD8 cDNAs,
indicating that CD8 does not appear to play a role in TL tetramer
binding in contrast to H-2Kb.
|
Given that the anti-CD8 Abs that interact with CD8-MHC
class I contact residues blocked both H-2Kb and
TL tetramer binding and given the strong homology (86%) between
H-2Kb and TL in the 3 domain (Fig. 3), we hypothesized that the 3 domain
of TL would contact CD8. To test this hypothesis, we created a panel of
CD8 mutants and tested the ability of the mutant forms of CD8
to bind to either the TL or H-2Kb tetramer by
flow cytometry (Fig. 4). All mutants
shown were expressed equivalent to or better than WT CD8. We found that
mutations in residues S31A/L, K62E, and N107A had strong effects on
both H-2Kb and TL binding, reducing tetramer
binding to 20% or less relative to WT CD8 (Fig. 4). These three
residues are located on the CD8 CDR1, 2, and 3 loops, respectively
(Fig. 5); they contact the negatively
charged loop of the 3 domain of MHC class I based on the murine
CD8-MHC class I cocrystal (16). Substituting S31 with
leucine, which has a much bulkier side chain, completely knocked out
binding of both tetramers (S31L) (Fig. 6
). Therefore, it appears that CD8
contacts the 3 domain of TL using similar contact residues as for
H-2Kb.
|
|
|
2m from the
CD8/H-2Kb cocrystal. For example, L29A had
no effect on TL tetramer binding, while binding of the
H-2Kb tetramer was reduced to 
30% (Fig. 4).
In addition, R8A completely abrogated H-2Kb
tetramer binding, but only reduced TL tetramer binding to 70% of WT
(Fig. 5). Making a more drastic change of this arginine to aspartic
acid did not dramatically alter the effect of this mutation on TL
tetramer binding as compared with the alanine substitution (Fig. 4).
Additionally, mutation of a residue that is not known to be a contact
residue with MHC class I also showed differences. Mutant K12E had a
dramatic effect on H-2Kb tetramer binding, but
had no effect on TL binding (K12E, or K12E,K13E) (Figs. 4 and 7). Mutant K13E alone also caused a small
decrease in H2-Kb tetramer binding (60% of WT),
but not as dramatic as with K12E. This mutation also had no effect on
TL tetramer binding. Staining with several anti-CD8 Abs binding
to different regions of the CD8 molecule was unaltered, indicating that
no gross conformational changes had occurred that were responsible for
the reduction in binding of H-2Kb tetramers. The
molecular basis for this effect is not known; however, indirect effects
on interaction between CD8 and the 2 domain of MHC class I are
possible.
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
with a
higher affinity than classical MHC class I molecules (19)
and demonstrates preferential binding to CD8. Our results support
this finding in that the TL tetramer bound CD8 transfectants
similarly to an anti-CD8 Ab. In contrast, a smaller number of cells
were positive with the H-2Kb tetramer, these
presumably being the higher and intermediate CD8-expressing cells.
To understand the molecular basis for this difference, we used a
mutational analysis to compare the interaction between CD8 with TL vs
MHC class I. We conclude that CD8 binds similarly to the 3 domain of
both TL and H-2Kb. This is based on the fact
that: 1) mutations in CD8 residues S31, K62, and N107 that contact a
negatively charged loop on the 3 domains of
H-2Kb eliminate or dramatically reduced the
ability of both TL and H-2Kb tetramers to
bind to CD8; 2) an anti-CD8 Ab, which binds to that
contact region, blocks CD8 binding to both tetramers; and 3) sequence
similarity (11 of 12 residues identical between TL and
H-2Kb) in the negatively charged loop on the 3
domains that contact CD8 (Fig. 3).
The residues on the side of one of the Ig domain subunits of CD8
containing the A and B strands make contact with
2m or the 2 domain of MHC class I in both
the murine and human CD8 cocrystals. We previously reported that
mutations in human CD8 residues L25 and R4 located on those strands
greatly reduced or abolished the interaction of human CD8 with MHC
class I (13). This finding was reproduced in this study in
that mutations in L29 and R8 (the murine homologous residues) reduced
binding of the H-2Kb tetramer to either 30% or
5% of WT. In contrast, those mutations bound TL tetramers 70% or
better compared with WT.
The H-2Kb tetramers were constructed with a human
2m because of reported greater stability,
while the TL tetramer was constructed with murine
2m. We do not believe that the differences can
be attributed to this species difference for the following reason: 1)
the contact residues for R8 on 2m (K58, D59)
are conserved between human and mouse 2m, and
2) using a cell-cell adhesion assay between COS-7 cells expressing
murine CD8 and a cell line expressing H-2Kb
proteins associated with murine 2m, the R8
mutation also ablated binding of the
H-2Kb-expressing cells (unpublished). In
addition, TL molecules refolded with human 2m
or mouse 2m bind with identical high affinity
to CD8 when measured using surface plasmon resonance (H.
Cheroutre and O. V. Naidenko, unpublished observations).
Another argument for a difference in interaction is our results with
mutant K12E either alone or in combination with K13E. This mutation had
a dramatic effect on H-2Kb tetramer binding to
CD8 transfectants (reducing binding to 10% of WT), but had no
effect on TL tetramer binding. K12 is not a known contact with MHC
class I and is located on the A strand of CD8, either facing the
2 domain of MHC class I if it is the 1 subunit of CD8 or out in
space if it is the 2 subunit. Because Ab and TL binding to this
mutant were not affected, mutation of this solvent-exposed residue
presumably has no major effect on the conformation of the protein. It
could be indirectly affecting the interaction with the
12 domains of MHC class I. Regardless of
the molecular basis for this effect, it indicates a major difference in
the interaction between H2-Kb and TL.
We also observed differences in the contribution of CD8 to the
interaction of tetramers with CD8. Although TL tetramers could bind to
COS-7 cells expressing CD8, blocking CD8 with an Ab that
reduced H-2Kb tetramer binding had no effect on
TL tetramer binding. Therefore, although CD8 is contributing to the
binding with H-2Kb, it seems unlikely that CD8
is involved in TL binding. There are two possible reasons that TL binds
similarly to CD8- and CD8-transfected cells, despite the
low binding affinity of TL for CD8 (19). Since
cotransfecting COS-7 cells with CD8 and CD8 results in some
CD8 homodimer expression, the TL tetramer could be binding to
CD8 alone. Alternatively, the high levels of CD8 expressed as
a heterodimer may be sufficient for TL tetramer binding, such that a
single CD8 Ig domain would be contacting TL and not the
-chain.
Since soluble TL was shown to bind CD8 with a 10 times higher
affinity than H-2Kb, it was striking that we did
not find any unique contact residues on CD8 for TL. In fact, fewer
residues on CD8 appeared to be involved in the interaction as compared
with H-2Kb. One possible explanation is that some
residues may interfere with CD8/MHC class I binding, thus reducing the
overall affinity as compared with TL. The two residues in the 3
domain that are different between TL and H-2Kb
and are known contact residues are at position 198, a charge
substitution (K to D in TL), and at 228, a nonpolar to a polar
substitution (M to T in TL). When comparing the affinity of
CD8 for several class I molecules and to HLA-E and HLA-G, Gao et
al. (24) found that a single amino acid change in the 3
domain of MHC class I could lead to significant differences in binding
affinities. Therefore, one or both of these amino acid changes may
significantly contribute to changes in affinity.
In this study, we have shown that MHC class I tetramers, while a valuable tool for monitoring Ag-specific T cell responses, can also be used to study protein-protein interactions.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
2 Current address: Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110.
3 Address correspondence and reprint requests to Dr. Paula B. Kavathas, Department of Laboratory Medicine, Yale University School of Medicine, 333 Cedar Street, P.O. Box 208035, New Haven, CT 06520-8035. E-mail address: paula.kavathas{at}yale.edu
4 Abbreviations used in this paper: TL, thymic leukemia Ag; 2m, 2-microglobulin; CDR, complementarity-determining region; WT, wild type; BI, binding index; BirA, biotin protein ligase.
Received for publication November 9, 2001. Accepted for publication January 31, 2002.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
, but not mouse CD8, can be expressed in the absence of CD8 as a homodimer. J. Immunol. 164:833.3 domain of HLA-A2. Nature 345:41.[Medline]
2 and 3 domains of MHC class I. J. Exp. Med. 182:1275./ homodimer in binding to major histocompatibility complex class I molecules: support for a bivalent model. Proc. Natl. Acad. Sci. USA 91:1716. relative to MHC class I. J. Immunol. 162:846. and HLA-A2. Nature 387:630.[Medline]
ectodomain fragment in complex with H-2Kb. Immunity 9:519.[Medline]
with the non classical MHC class I molecule, TL, alters TCR-induced responses. Science 294:1936.. J. Biol. Chem. 275:15232.This article has been cited by other articles:
|
|
 |
|
  R. Wang, K. Natarajan, and D. H. Margulies Structural Basis of the CD8{alpha}{beta}/MHC Class I Interaction: Focused Recognition Orients CD8{beta} to a T Cell Proximal Position J. Immunol., August 15, 2009; 183(4): 2554 - 2564. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Rettig, L. McNeill, N. Sarner, P. Guillaume, I. Luescher, M. Tolaini, D. Kioussis, and R. Zamoyska An Essential Role for the Stalk Region of CD8{beta} in the Coreceptor Function of CD8 J. Immunol., January 1, 2009; 182(1): 121 - 129. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Olivares-Villagomez, Y. V. Mendez-Fernandez, V. V. Parekh, S. Lalani, T. L. Vincent, H. Cheroutre, and L. Van Kaer Thymus leukemia antigen controls intraepithelial lymphocyte function and inflammatory bowel disease PNAS, November 18, 2008; 105(46): 17931 - 17936. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. A. Benoit and R. Tan Xenogeneic beta2-Microglobulin Substitution Affects Functional Binding of MHC Class I Molecules by CD8+ T Cells J. Immunol., September 15, 2007; 179(6): 3588 - 3595. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. A. Doyle, J. Zhou, M. J. Wolff, B. P. Harvey, R. M. Roman, R. J. Gee, R. A. Koski, and M. J. Mamula Isoaspartyl Post-translational Modification Triggers Anti-tumor T and B Lymphocyte Immunity J. Biol. Chem., October 27, 2006; 281(43): 32676 - 32683. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Devine, D. Thakral, S. Nag, J. Dobbins, M. E. Hodsdon, and P. B. Kavathas Mapping the Binding Site on CD8beta for MHC Class I Reveals Mutants with Enhanced Binding J. Immunol., September 15, 2006; 177(6): 3930 - 3938. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Attinger, L. Devine, Y. Wang-Zhu, D. Martin, J.-h. Wang, E. L. Reinherz, M. Kronenberg, H. Cheroutre, and P. Kavathas Molecular Basis for the High Affinity Interaction between the Thymic Leukemia Antigen and the CD8{alpha}{alpha} Molecule J. Immunol., March 15, 2005; 174(6): 3501 - 3507. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. E. Kerry, J. Buslepp, L. A. Cramer, R. Maile, L. L. Hensley, A. I. Nielsen, P. Kavathas, B. J. Vilen, E. J. Collins, and J. A. Frelinger Interplay between TCR Affinity and Necessity of Coreceptor Ligation: High-Affinity Peptide-MHC/TCR Interaction Overcomes Lack of CD8 Engagement J. Immunol., November 1, 2003; 171(9): 4493 - 4503. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. S. Wong, X. Wang, T. Witte, L. Nie, N. Carvou, P. Kern, and H.-C. Chang Stalk Region of {beta}-Chain Enhances the Coreceptor Function of CD8 J. Immunol., July 15, 2003; 171(2): 867 - 874. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. K. Davis, R. G. Cook, R. R. Rich, and J. R. Rodgers Hyperconservation of the Putative Antigen Recognition Site of the MHC Class I-b Molecule TL in the Subfamily Murinae: Evidence That Thymus Leukemia Antigen Is an Ancient Mammalian Gene J. Immunol., December 15, 2002; 169(12): 6890 - 6899. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Konno, K. Okada, K. Mizuno, M. Nishida, S. Nagaoki, T. Toma, T. Uehara, K. Ohta, Y. Kasahara, H. Seki, et al. CD8alpha alpha memory effector T cells descend directly from clonally expanded CD8alpha +beta high TCRalpha beta T cells in vivo Blood, December 1, 2002; 100(12): 4090 - 4097. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. A. Weber, A. Attinger, C. C. Kemball, J. L. Wigal, J. Pohl, Y. Xiong, E. L. Reinherz, H. Cheroutre, M. Kronenberg, and P. E. Jensen Peptide-Independent Folding and CD8{alpha}{alpha} Binding by the Nonclassical Class I Molecule, Thymic Leukemia Antigen J. Immunol., November 15, 2002; 169(10): 5708 - 5714. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
) and CD8
). Cells were pretreated with Abs against CD8
.
