 |
Introduction |
During thymocyte development, the genes coding for
TCR-
and -
, pre-TCR-
(pT
), and the associated CD3 proteins (CD3
,
,
, and
) are expressed in a
temporal order (1). The pre-TCR-CD3 complex, consisting of pT
, TCR-
, and CD3 proteins, plays a major role
in early thymocyte development and in the transition from CD4
CD8
(double negative, DN) to CD4+CD8+ (double positive, DP) cells, as targeted mutations in pT
,
TCR-
, RAG, and CD3 genes all result in an arrest of T
cell development at the DN CD44
CD25+ check point
(2, 3). Subsequently, TCR-
replaces pT
and the resulting TCR-CD3 complex mediates signal transduction cascades leading to further T cell development (2). Compared
with 
T cell development, 
T cell development is less
defined (4, 5). The majority of thymic 
T cells do not
express CD4 or CD8 antigens (6), and pT
and TCR-
are not involved the development of 
T cells (7, 8).
However, CD3 proteins are required for the development
of this lineage (2).
Ample biochemical studies have shown that the CD3
proteins are important for assembly and efficient surface expression of TCR (9). In each TCR-CD3 complex, there
are two copies of CD3
and CD3
, yet only one copy of
the highly homologous CD3
and CD3
(10). CD3
forms heterodimers with CD3
and CD3
, and can also
exist as a CD3
homodimer, whereas CD3
exists as a
CD3
homodimer (11, 13, 14). TCRs lacking CD3
,
,
, or
can reach the cell surface, albeit 10-100-fold less efficiently than wild-type receptors, because of a certain degree of redundancy in their assembly potential (15, 16). In
immature thymocytes, the CD3 proteins are expressed (17-
19), before the expression of pT
and TCR-
(1). Thus,
CD3 proteins can be a part of the pre-TCR-CD3 complex
or part of a clonotype-independent CD3 (CIC) complex
(20). In these complexes, CD3
dimers are consistently detected (20, 21), and some studies indicated the presence of a small quantity of CD3
dimers (18). This led to
the notion that CD3
may be preferentially required over
CD3
in the assembly of pre-TCR complexes (22).
Recent studies on mutant mice deficient in either the
CD3
or CD3
gene in part support this notion. Whereas
transition from DN to DP 
thymocytes appears to be
normal in CD3
/
mice (23), 
T cell development in
CD3
/
mice is blocked at the DN CD44
CD25+ check
point (24). However, the blockade in T cell development in
CD3
/
mice is incomplete, as small numbers of DP thymocytes were found and TCR-
+ T cells were detected
in the periphery (24). Moreover, in either mutant a considerable number of 
T cells is present (23, 24). Therefore, it
is likely that CD3
and CD3
play an essential, yet to some
extent redundant, role in early development of T cells.
To examine the issue of partial overlap in function between CD3
and CD3
, a mouse strain with a disruption
in both the CD3
and CD3
genes (CD3

/
) would be
useful. A CD3

/
mouse, however, could not be generated by breeding the CD3
/
and CD3
/
mice, because the genes coding for CD3
,
, and
are located in a
single gene cluster and a mere 1.4-kb intergenic sequence separates the first exons of CD3
and CD3
genes (25).
Therefore, we generated CD3

/
mice by deleting the
promoters and exons 1 of both genes.
 |
Materials and Methods |
Generation of CD3

/
Mice.
The targeting construct was
generated by standard methods. In brief, a genomic DNA clone
containing a 15.5-kb fragment of CD3
genes was isolated from
a 129/sv mouse genomic DNA library (provided by Dr. Manley
Huang, GenPharm Int., Mountain View, CA) and subcloned into
pBluescriptSK+ (Stratagene, La Jolla, CA). A 2.8-kb SalI-XhoI
DNA fragment containing the PGK-TKr gene was isolated from
pPGK-TK (provided by Dr. Manley Huang), and ligated to the
XhoI site of pPGK-hygromyciner (hygr) (a gift of Dr. Richard
Mortensen). A 1.9-kb XbaI-XbaI intronic fragment between exon
1 and 2 of CD3
was obtained by XbaI digestion of the 15.5-kb
CD3
genomic DNA fragment. And a 3-kb intronic fragment
between exon 1 and 2 of CD3
was obtained by first subcloning a
5-kb EcoRI-XbaI fragment into SK+ followed by a HindIII cut, so that a HindIII site from the polylinker region of the plasmid was
transferred to one end of the 3-kb fragment. The 1.9-kb XbaI-XbaI fragment and the 3-kb HindIII-HindIII fragment were
inserted into the 5' and 3' sites of the PGK-Hygr gene. In the
resulting construct, a 3.1-kb DNA fragment containing the 1.4-kb
intergenic DNA fragment between the CD3
and CD3
genes and exons 1 of both genes were replaced by the 2.8-kb PGK-Hygr
cassette. 10 µg of purified targeting molecules were electroporated into 107 J-1 ES cells. ES cells were positively selected by hygromycin-B at 200 µg/ml and negatively selected by FIAU at 0.2 µM. 355 clones were selected and examined by Southern blots for
homologous recombination using a 0.8-kb (StuI-XbaI) 5' probe
located outside of the construct. Eight clones were identified as targeted clones, which were confirmed by another Southern analysis
with a hygr probe. Four of the targeted clones were injected into
the blastocysts of either C57BL/6 or BALB/C origin, and 90-
100% fur color chimerism was observed in 45 founder mice. Test
breeding of the chimeras indicated that all of the males (n = 28 from 3 embryonic stem [ES] clones) transmitted the ES cell
genome. Four males were mated to C57BL/6 females to generate
heterozygous mice, and homozygous CD3

/
lines were obtained by sibling breeding. Identical results were obtained from
homozygous CD3

/
lines of different ES clones.
Flow Cytometric Analysis.
Single cell suspensions of thymocytes, LN cells, spleen cells, PBL, and small intestine intraepithelial lymphocytes (iIEL) were prepared as described (26, 27).
Three-color staining of the cells was performed as previously reported elsewhere (28).
RNA Analysis.
Northern blot analysis was performed as described (29).
 |
Results |
Generation of CD3

/
Mice.
To generate mice deficient in both CD3
and CD3
gene expression, a 3.1-kb
DNA fragment containing the promoters (25) and exons 1 of the CD3
and CD3
genes was replaced by a PGK-Hygr cassette (Fig. 1 A). The PGK-hygr cassette was chosen here over the PGK-neor cassette to prevent a possible
suppressive effect of the PGK-neor on neighboring gene
expression (30, 31). Homozygous mice carrying this mutation in the CD3
and
genes were generated (Fig. 1 B).
Northern blot analysis demonstrated that the expression of
both CD3
and CD3
mRNA was absent in the CD3

/
thymocytes (Fig. 2). Moreover, no aberrant expression of
the truncated CD3
or
mRNAs were ever detected in
Northern blotting of thymocytes from more than 20 CD3

/
mice. However, the expression of the neighboring CD3
gene and the nonlinked CD3
was normal
(Fig. 2), and pT
expression was detected (data not
shown).

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Fig. 1.
Disruption of CD3 genes. (A) Diagram of the CD3 targeting vector for homologous recombination. Exons 1-5 of the CD3
gene and exon 1 of the CD3 gene are numbered. Arrows indicate the
transcriptional orientations of the CD3 genes. The 0.8-kb probe was
used for screening the ES cell clones and for Southern analysis of tail
DNA. (B) Southern blot analysis of tail DNA.
|
|

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Fig. 2.
TCR-CD3 expression
in the CD3  / mice. Northern
blotting of thymocytes from wt,
RAG / and CD3  / mice for
the expression of CD3 , , , , and
TCR- and - . The respective
probes are indicated on the left, and
the sizes on the right. Two mice of
each type were analyzed in this blot.
|
|

T Cell Development in the CD3

/
Mice.
Total cellularity of the thymi of CD3

/
mice was 2-5% of
that in wild-type or heterozygous littermates (Fig. 3 A).
Flow cytometric analysis of the thymocytes showed that
these cells are DN, with the majority of them being
CD44
CD25+c-Kit
Sca-1+, identical to the thymocytes
found in RAG
/
mice (Fig. 3 B). Northern blot analyses
of the thymocytes of CD3

/
mice did not detect the
mRNA for rearranged TCR-
and TCR-
genes, whereas
only the 1.0-kb germline C
mRNA was detectable (Fig. 2). Consistent with these analyses, no mature 
+ T cells
were detected in the LN, the spleen, or the gut of the CD3

/
mice (Figs. 3 C and 4 C, Table 1). B cell development appeared unaffected (Table 1). Taken together, 
T cell development in CD3

/
mice is blocked at the
same DN CD44
CD25+ check point as RAG
/
mice
(32, 33).

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Fig. 3.
T cell deficiency in the CD3  / mice. (A) Thymic cellularity of the mutant mice. Each symbol represents the total number of
thymocytes from a mouse. The ages of the mice are indicated. For each
age group, the average number of thymocytes from mutant mice was
compared with that of wild-type (including CD3 +/ ) littermates or
age-matched, wild-type mice (28). (B) Flow cytometric analysis of thymocytes from CD3  / , RAG-2 / and wild-type mice for surface expression of CD4, CD8, CD44, CD25, Sca-1, and c-Kit. (C) Flow cytometric analysis of peripheral lymph node cells for surface expression of
CD4 and CD8.
|
|

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Fig. 4.
Flow cytometric analysis of the  T cell compartment in
CD3  / mice. (A) Thymocytes were stained with anti-TCR- -
biotinylated (detected with RED-670), anti-CD3-PE, and anti-CD4/
CD8-FITC. (Left) Profile of CD4/CD8 expression. (Right) Profile of
TCR- and CD3 expression in the analytically gated DN cells. (B)
Lymph node cells were similarly analyzed as in A, except that a mixture of
FITC-conjugated antibodies, i.e., anti-CD4, -CD8, -TCR- , -B220,
-Mac-3, and Gr-1 (collectively termed Lin), was used. (C) Expression of
TCR- and TCR- in iIEL. (D) iIEL were stained with anti-CD8 ,
anti-CD8 , and anti-CD32. (Left) Profile of CD8 /CD8 expression.
(Right) Profile of CD32 expression in the analytically gated CD8 + cells.
The CD8 + cells were all CD8 + and were predominantly CD32+. (E)
iIEL were stained with anti-CD8 , anti-B220, and anti-CD32, and the
profile of CD8 /B220 expression in the analytically gated CD32+ cells is
shown.
|
|

T Cell Development in CD3

/
Mice.
Next, 
T
cell development in CD3

/
mice was examined. As
shown in Fig. 4, A and B, 
T cells were absent in the
thymus and periphery of CD3

/
mice. Since 
T cells
normally account for only a very small fraction of thymocytes and peripheral T cells, we assessed 
T cell development in the small intestine, where 
T cells represent a major population of the iIEL in wild-type mice. In
CD3

/
mice, 
T cells were again nondetectable in
the intestine (Fig. 4 C). However, normal number of
CD8
+B220+CD32+NK1.1
cells, representing T cell
progenitors in the gut (27) could be detected in the gut of
CD3

/
mice (Fig. 4, C-E, Table 1, and data not
shown). Therefore, these analyses indicate that deficiency
in CD3
and
completely blocked 
T cell development
beyond the CD8
+ stage.
 |
Discussion |
We report here that in the CD3

/
double mutant
mice, intrathymic development is completely arrested at
the DN CD44
CD25+ prothymocyte stage, a central
check point at which pre-TCR begins to mediate further
thymocyte differentiation into the DP stage. This observation indicates that the function of pre-TCR is completely abrogated in CD3

/
mice. In contrast, in recently reported CD3
/
mice, thymic development is undisturbed
up to the DP stage (23), whereas the transition from DN to
DP stages was severely but not completely blocked in
CD3
/
mice (24). The phenotypes of CD3
/
and
CD3
/
mice are consistent with the biochemical evidence that CD3
is preferentially required over CD3
in
prothymocytes for the assembly of the pre-TCR-CD3
complex (22). However, the present data revealed that
CD3
also participated in vivo in the assembly and function of the pre-TCR-CD3 complex. Moreover, small
numbers of TCR-
+ T cells were detected in the periphery of CD3
/
and CD3
/
mice, but were absent in
CD3

/
mice. These observations are consistent with
the biological evidence that in mature T cells, the TCR-
CD3 complex lacking either CD3
or
could sometimes
be detected on the cell surface at reduced levels. However,
no surface expression of the TCR-CD3 complex could be
detected in cells lacking both CD3
and
(15, 16). Taken
together, CD3
and CD3
collectively play an essential, yet partially overlapping, role in the assembly and function
of the pre-TCR. It is most likely that in the absence of
CD3
and CD3
, pre-TCR cannot be expressed on the
surface of prothymocytes.
In addition to the structural requirement, CD3
and
CD3
may regulate pre-TCR function through the signaling capacity of the immunoreceptor tyrosine-based activation motifs (ITAMs) presented in their cytoplasmic domains (34). It is known that not every ITAM plays a
distinct role in pre-TCR function. For instance, pre-TCR
function is competent in mutant mice deficient in the CD3
cytoplasmic domain (35). Moreover, the defect in
pre-TCR function in CD3
/
(24), CD3
/
(36), or
RAG
/
(19, 27, 37) mice can be overcome by anti-CD3
-mediated cross-linking. However, the same anti-CD3
treatment in vivo in CD3

/
mice failed to relieve the block at the DN check point (data not shown).
Since the anti-CD3
antibody used in all of these studies,
namely 2C11 (or 500A2), binds CD3
efficiently when either CD3
or CD3
is presented but poorly when both
CD3
and CD3
are missing (38; data not shown), the lack
of thymocyte differentiation upon 2C11 treatment of
CD3

/
mice might be explained by the following nonexclusive possibilities: (a) pre-TCR could not be expressed
on the surface of CD3

/
prothymocytes; (b) the inefficient binding of 2C11 to CD3
on the surface of CD3

/
prothymocytes results in a weak signal that is below the
threshold level for further thymic development; and (c) the
cytoplasmic domains of CD3
and CD3
collectively play
an essential role in pre-TCR function. The last possibility,
nevertheless, is less likely because it has been shown that
under artificial circumstances, either CD3
or CD3
cytoplasmic domain alone can independently generate signals
for thymocyte development to the DP stage (39). Thus, the
ultimate assessment of the physiological role of the cytoplasmic domains of CD3
and CD3
awaits the generation
of mutant mice in which the cytoplasmic domains of
CD3
and CD3
are deleted.
An important observation of this study was that 
T cell
development was completely blocked in the CD3

/
mice. In comparison, 
T cell development was partially
blocked in the CD3
/
mice and was undisturbed in
CD3
/
mice (23, 24). Thus, this study demonstrated that
CD3
also plays a role in regulating the development of the

T cell lineage, and CD3
and CD3
collectively are essential for 
T cell development. Like their regulation of

T cell development, CD3
and CD3
may regulate 
T cell development by their structural contribution and/or
signaling capacity. Nevertheless, the function of CD3
or
CD3
for 
T cells may not be a duplication of their respective roles for 
T cells. For instance, although surface
expression of TCR-
is severely reduced (8-10-fold) in
CD3
/
mice, their TCR-
expression is only mildly
(less than twofold) reduced (23). On the other hand, severe
reduction of both TCR-
and TCR-
expression in
CD3
/
mice indicated a pivotal role of CD3
in the assembly of TCR-
-CD3 and TCR-
-CD3 complexes
(24). Taken together, it is likely that the complete block in

T cell development in CD3

/
mice was a result of
the incomplete TCR-
-CD3 complex not being expressed on cell surface in the absence of CD3
and CD3
.
It remains to be investigated whether the cytoplasmic domains of CD3
and CD3
also have distinct functions in
the development of 
T cells.
In conclusion, in the CD3

/
mice, early thymic development mediated by pre-TCR was completely blocked,
and TCR-
+ and TCR-
+ T cells were absent. These
observations are different from those made on either
CD3
/
or CD3
/
mice, in which pre-TCR function
was either undisturbed or incompletely blocked, as TCR-
+ and TCR-
+ T cells were detected in the periphery.
Taken together, these studies demonstrated that CD3
and
CD3
play an essential, yet partially overlapping, role in
the development of both 
and 
T cell lineages.
Address correspondence to Cox Terhorst, Division of Immunology, Beth Israel Deaconess Medical Center,
Harvard Medical School, Boston, MA 02215. Phone: 617-667-7147; Fax: 617-667-7140; E-mail: cterhors
@
This work was supported by National Institutes of Health grants CA 74233 (to B. Wang) and AI35714 and
R37-17651 (to C. Terhorst).
1.
|
Wilson, A., and
H.R. MacDonald.
1995.
Expression of genes
encoding the pre-TCR and CD3 complex during thymus
development.
Int. Immunol.
7:
1659-1664
[Abstract].
|
2.
|
Tanaka, Y.,
L. Ardouin,
A. Gillet,
S.Y. Lin,
A. Magnan,
B. Malissen, and
M. Malissen.
1995.
Early T-cell development
in CD3-deficient mice.
Immunol. Rev.
148:
171-199
[Medline].
|
3.
|
Wang, B.,
S.J. Simpson,
G.A. Hollander, and
C. Terhorst.
1997.
Development of T lymphocyte and natural killer cell
functions after bone marrow transplantation of severely immunodeficient mice.
Immunol. Rev.
157:
53-60
[Medline].
|
4.
|
Shortman, K.,
L. Wu,
K.A. Kelly, and
R. Scollay.
1991.
The
beginning and the end of the development of TCR gamma
delta cells in the thymus.
Curr. Top. Microbiol. Immunol.
173:
71-80
[Medline].
|
5.
|
Dudley, E.C.,
M. Girardi,
M.J. Owen, and
A.C. Hayday.
1995.
/ and / T cells can share a late common precursor.
Curr. Biol.
5:
659-669
[Medline].
|
6.
|
Zorbas, M., and
R. Scollay.
1993.
Development of / T
cells in the adult murine thymus.
Eur. J. Immunol.
23:
1655-1660
[Medline].
|
7.
|
Mombaerts, P.,
A.R. Clarke,
M.A. Rudnicki,
J. Iacomini,
S. Itohara,
J.J. Lafaille,
L. Wang,
Y. Ichikawa,
R. Jaenisch,
M.L. Hooper, and
S. Tonegawa.
1992.
Mutations in T-cell antigen
receptor genes and block thymocyte development at different stages.
Nature.
360:
225-231
[Medline].
|
8.
| Fehling, H.J., A. Krotkova, C. Saint-Ruf, and H. von Boehmer. 1995. Crucial role of the pre-T-cell receptor gene in
development of / but not / T cells. Nature. 375:795-798
(see published erratum 378:419).
|
9.
|
Exley, M.,
C. Terhorst, and
T. Wileman.
1991.
Structure, assembly and intracellular transport of the T cell receptor for
antigen.
Semin. Immunol.
3:
283-297
[Medline].
|
10.
|
de la Hera, A.,
U. Muller,
C. Olsson,
S. Isaaz, and
A. Tunnacliffe.
1991.
Structure of the T cell antigen receptor (TCR):
two CD3 subunits in a functional TCR-CD3 complex.
J.
Exp. Med.
173:
7-17
[Abstract].
|
11.
|
Rutledge, T.,
P. Cosson,
N. Manolios,
J.S. Bonifacino, and
R.D. Klausner.
1992.
Transmembrane helical interactions: chain dimerization and functional association with the T cell
antigen receptor.
EMBO (Eur. Mol. Biol. Organ.) J.
11:
3245-3254
[Abstract].
|
12.
|
Punt, J.A.,
J.L. Roberts,
K.P. Kearse, and
A. Singer.
1994.
Stoichiometry of the T cell antigen receptor (TCR) complex: each TCR-CD3 complex contains one TCR- , one
TCR- , and two CD3 epsilon chains.
J. Exp. Med.
180:
587-593
[Abstract].
|
13.
|
Alarcon, B.,
S.C. Ley,
F. Sanchez-Madrid,
R.S. Blumberg,
S.T. Ju,
M. Fresno, and
C. Terhorst.
1991.
The CD3- and
CD3- subunits of the T cell antigen receptor can be expressed within distinct functional TCR/CD3 complexes.
EMBO (Eur. Mol. Biol. Organ.) J.
10:
903-912
[Abstract].
|
14.
|
Manolios, N.,
F. Letourneur,
J.S. Bonifacino, and
R.D. Klausner.
1991.
Pairwise, cooperative and inhibitory interactions describe the assembly and probable structure of the
T-cell antigen receptor.
EMBO (Eur. Mol. Biol. Organ.) J.
10:
1643-1651
[Abstract].
|
15.
|
Hall, C.,
B. Berkhout,
B. Alarcon,
J. Sancho,
T. Wileman, and
C. Terhorst.
1991.
Requirements for cell surface expression of the human TCR/CD3 complex in non-T cells.
Int.
Immunol.
3:
359-368
[Abstract].
|
16.
|
Kappes, D.J., and
S. Tonegawa.
1991.
Surface expression of
alternative forms of the TCR/CD3 complex.
Proc. Natl.
Acad. Sci. USA.
88:
10619-10623
[Abstract].
|
17.
|
Punt, J.A.,
R.T. Kubo,
T. Saito,
T.H. Finkel,
S. Kathiresan,
K.J. Blank, and
Y. Hashimoto.
1991.
Surface expression of a
T cell receptor (TCR- ) chain in the absence of TCR- ,
- , and - proteins.
J. Exp. Med.
174:
775-783
[Abstract].
|
18.
|
Groettrup, M.,
A. Baron,
G. Griffiths,
R. Palacios, and
H. von Boehmer.
1992.
T cell receptor (TCR) beta chain homodimers on the surface of immature but not mature , , chain deficient T cell lines.
EMBO (Eur. Mol. Biol. Organ.) J.
11:
2735-2745
[Abstract].
|
19.
|
Shinkai, Y., and
F.W. Alt.
1994.
CD3 epsilon-mediated signals rescue the development of CD4+CD8+ thymocytes in
RAG-2 / mice in the absence of TCR chain expression.
Int. Immunol.
6:
995-1001
[Abstract].
|
20.
|
Wiest, D.L.,
K.P. Kearse,
E.W. Shores, and
A. Singer.
1994.
Developmentally regulated expression of CD3 components
independent of clonotypic T cell antigen receptor complexes
on immature thymocytes.
J. Exp. Med.
180:
1375-1382
[Abstract].
|
21.
|
Berger, M.A.,
V. Dave,
M.R. Rhodes,
G.C. Bosma,
M.J. Bosma,
D.J. Kappes, and
D.L. Wiest.
1997.
Subunit composition of pre-T cell receptor complexes expressed by primary
thymocytes: CD3 is physically associated but not functionally required.
J. Exp. Med.
186:
1461-1467
[Abstract/Free Full Text].
|
22.
|
Borst, J.,
H. Jacobs, and
G. Brouns.
1996.
Composition and
function of T-cell receptor and B-cell receptor complexes on
precursor lymphocytes.
Curr. Opin. Immunol.
8:
181-190
[Medline].
|
23.
|
Dave, V.P.,
Z. Cao,
C. Browne,
B. Alarcon,
G. Fernandez-Miguel,
J. Lafaille,
A. de la Hera,
S. Tonegawa, and
D.J. Kappes.
1997.
CD3 deficiency arrests development of the
/ but not the / T cell lineage.
EMBO (Eur. Mol. Biol.
Organ.) J.
16:
1360-1370
[Abstract/Free Full Text].
|
24.
|
Haks, M.C.,
P. Krimpenfort,
J. Borst, and
A.M. Kruisbeek.
1998.
The CD3gamma chain is essential for development of
both the TCR alpha beta and TCR gamma delta lineages.
EMBO (Eur. Mol. Biol. Organ.) J.
17:
1871-1882
[Free Full Text].
|
25.
|
Saito, H.,
T. Koyama,
K. Georgopoulos,
H. Clevers,
W.G. Haser,
T. LeBien,
S. Tonegawa, and
C. Terhorst.
1987.
Close linkage of the mouse and human CD3 gamma- and
delta-chain genes suggests that their transcription is controlled
by common regulatory elements.
Proc. Natl. Acad. Sci. USA.
84:
9131-9134
[Abstract].
|
26.
|
Liu, C.P.,
R. Ueda,
J. She,
J. Sancho,
B. Wang,
G. Weddell,
J. Loring,
C. Kurahara,
E.C. Dudley,
A. Hayday, et al
.
1993.
Abnormal T cell development in CD3- / mutant mice and
identification of a novel T cell population in the intestine.
EMBO (Eur. Mol. Biol. Organ.) J.
12:
4863-4875
[Abstract].
|
27.
|
She, J.,
S.J. Simpson,
A. Gupta,
G. Hollander,
C. Levelt,
C.P. Liu,
D. Allen,
N. van Houten,
B. Wang, and
C. Terhorst.
1997.
CD16-expressing CD8 + T lymphocytes in
the intestinal epithelium: possible precursors of Fc gammaR-CD8 + T cells.
J. Immunol.
158:
4678-4687
[Abstract].
|
28.
|
Wang, B.,
C.N. Levelt,
M. Salio,
D.-X. Zheng,
J. Sancho,
C.-P. Liu,
J. She,
M. Huang,
K. Higgins,
M.-J. Sunshine, et al
.
1995.
Over-expression of CD3 transgenes blocks T lymphocyte development.
Int. Immunol.
7:
435-448
[Abstract].
|
29.
|
Levelt, C.N.,
B. Wang,
A. Ehrfeld,
C. Terhorst, and
K. Eichmann.
1995.
Regulation of T cell receptor (TCR)-beta
locus allelic exclusion and initiation of TCR- locus rearrangement in immature thymocytes by signaling through the
CD3 complex.
Eur. J. Immunol.
25:
1257-1261
[Medline].
|
30.
|
Malissen, M.,
A. Gillet,
L. Ardouin,
G. Bouvier,
J. Trucy,
P. Ferrier,
E. Vivier, and
B. Malissen.
1995.
Altered T cell development in mice with a targeted mutation of the CD3-
gene.
EMBO (Eur. Mol. Biol. Organ.) J.
14:
4641-4653
[Abstract].
|
31.
|
Olson, E.N.,
H.H. Arnold,
P.W. Rigby, and
B.J. Wold.
1996.
Know your neighbors: three phenotypes in null mutants of the myogenic bHLH gene MRF4.
Cell.
85:
1-4
[Medline].
|
32.
|
Mombaerts, P.,
J. Iacomini,
R.S. Johnson,
K. Herrup,
S. Tonegawa, and
V.E. Papaioannou.
1992.
Rag-1-deficient
mice have no mature B and T lymphocytes.
Cell.
68:
869-877
[Medline].
|
33.
|
Shinkai, Y.,
G. Rathbun,
K.-P. Lam,
E.M. Oltz,
V. Stewart,
M. Mendelsohn,
J. Charron,
M. Datta,
F. Young,
A.M. Stall, and
F.W. Alt.
1992.
Rag-2-deficient mice lack mature lymphocytes owing to inability to initiate V(D)J rearrangement.
Cell.
68:
855-867
[Medline].
|
34.
|
Cambier, J.C..
1995.
Antigen and Fc receptor signaling. The
awesome power of the immunoreceptor tyrosine-based activation motif (ITAM).
J. Immunol.
155:
3281-3285
[Medline].
|
35.
|
Shores, E.W.,
K. Huang,
T. Tran,
E. Lee,
A. Grinberg, and
P.E. Love.
1994.
Role of TCR chain in T cell development and selection.
Science.
266:
1047-1050
[Medline].
|
36.
|
Levelt, C.N.,
P. Mombaerts,
B. Wang,
H. Kohler,
S. Tonegawa,
K. Eichmann, and
C. Terhorst.
1995.
Regulation of
thymocyte development through CD3: functional dissociation between p56lck and CD3 in early thymic selection.
Immunity.
3:
215-222
[Medline].
|
37.
|
Levelt, C.N.,
P. Mombaerts,
A. Iglesias,
S. Tonegawa, and
K. Eichmann.
1993.
Restoration of early thymocyte differentiation in T-cell receptor -chain-deficient mutant mice by
transmembrane signaling through CD3 epsilon.
Proc. Natl.
Acad. Sci. USA.
90:
11401-11405
[Abstract].
|
38.
|
Bonifacino, J.S.,
C.K. Suzuki,
J. Lippincott-Schwartz,
A.M. Weissman, and
R.D. Klausner.
1989.
Pre-Golgi degradation
of newly synthesized T cell antigen receptor chains: intrinsic
sensitivity and the role of subunit assembly.
J. Cell Biol.
109:
73-83
[Abstract].
|
39.
|
Shinkai, Y.,
A. Ma,
H.L. Cheng, and
F.W. Alt.
1995.
CD3
epsilon and CD3 cytoplasmic domains can independently
generate signals for T cell development and function.
Immunity.
2:
401-411
[Medline].
|