| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Molecular Immunology, Medical Institute of Bioregulation, Kyushu University, Higashi-Ku, Fukuoka, Japan The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
-globulin (NP-CG).
Production of NP-specific IgG1 Abs was slightly reduced but clearly
detectable. The affinity of Abs produced was comparable to that in
wild-type mice. Furthermore, somatic hypermutation occurred in the
heavy-chain variable region at the same level as that in wild-type
mice. Therefore, we conclude that isotype switching and affinity
maturation occur normally in lyn-/- mice
without the formation of GCs. The results lead to a speculation that
Lyn may not play a role in induction of isotype switching or affinity
maturation, despite being downstream of the signals from the B cell Ag
receptor complex and CD40, and that GC architecture may not be
absolutely essential for affinity maturation. |
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
(CD79a) and Igß (CD79b) subunits, which couple sIgM to protein
tyrosine kinases (PTKs) (1). The Srk family kinases, one class of PTKs,
are activated by cross-linking of the BCR (2, 3, 4), resulting in
phosphorylation of several proteins including themselves, Ig, and
Igß (5), phospholipase C (PLC) (6), phosphatidylinositol-3
(PI-3) kinase (7), the proto-oncoprotein Vav (8), Ras GTPase-activating
protein (9), Shc (10), HS1 (11), and Syk kinase (12).
One of the Src family kinase members, Lyn, is expressed preferentially
in hemopoietic cells (13), especially in B cells, in
monocytes/macrophages, and in neural tissue cells (14). Recent studies
have shown that Lyn is physically associated with a number of
hemopoietic cell surface receptors such as the BCR (2, 3), CD40 (15),
LPS receptor (CD14) (16), high affinity Fc
RI complex (17), IL-2R
(IL-2R) (18), and the granulocyte-CSF receptor (19). Lyn kinase is
activated shortly after the cross-linking of BCR (2, 3). The function
of Lyn in BCR-mediated signaling was first demonstrated in a
Lyn-deficient chicken B cell line, DT40 (20), in which cross-linking of
the BCR on Lyn-deficient DT40 cells evoked a delayed and slow
Ca2+ mobilization, despite the normal kinetics of
inositol-triphosphate turnover. Further, in murine and human B-lineage
lymphoma cells, Lyn was shown to be required for anti-sIgM-mediated
cell cycle arrest (21). Recent studies have also suggested a function
of Lyn in the signaling pathway through CD40 (15, 22), a member of the
TNFR superfamily, which plays an important role in B cell survival,
proliferation, memory, isotype switching, and apoptosis (23, 24). Lyn
was shown to be tyrosine phosphorylated directly by CD40 cross-linking,
resulting in activation of PLC2 and PI-3 kinase in human Daudi
cells (15).
Lyn-deficient (lyn-/-) mice, recently generated by gene targeting, showed splenomegaly with age and accumulated splenic lymphoblastoid cells expressing Mac1 Ag on the surface and IgM in the cytoplasm (25, 26). Despite reduced numbers of circulating B cells, lyn-/- mice had high concentrations of serum IgM, and many of them exhibited severe glomerulonephritis caused by immune complex-containing autoreactive Abs. Furthermore, B cells of lyn-/- mice showed several abnormalities in vitro (25, 26, 27). Splenic B cells from young lyn-/- mice were hyperresponsive to sIgM cross-linking (27), whereas the cells from aged lyn-/- mice were hyporesponsive (25, 26). The proliferative response to CD40 ligand (CD40L) was also greatly reduced in the B cells of lyn-/- mice, although addition of IL-4 restored the response (26, 27). In addition, splenic B cells of lyn-/- mice were impaired in the induction of Fas expression after CD40L stimulation, resulting in a reduced susceptibility to Fas-mediated apoptosis (27).
One of the phenotypes observed in lyn-/- mice was a defect in the ability to form germinal centers (GCs) (25). GCs are dynamic microenvironments of B cell differentiation that arise transiently in the B cell follicles of secondary lymphoid organs during thymus-dependent (TD) Ag responses (28). It is believed that GCs play an important role in affinity maturation following somatic hypermutation and generation of memory B cells (29, 30, 31, 32). The GCs have also been reported to play a role in isotype switching in human tonsils (33). However, there is a study demonstrated that GCs are not necessary for isotype switching in the mouse (34), and this was confirmed by the work of Toellner et al. showing the appearance of sterile switching transcripts in Ag-activated B cells of the outer periarteriolar lymphatic sheath (35). The help of activated T cells is required for these responses (32) through the interaction between CD40 and CD40L, as well as B7-1/B7-2 and CD28/CTLA-4 (36), and appears to operate in a dose-dependent fashion (37).
Recently, many mutant mice generated by gene targeting have been found
to lack GC. These include MHC class II-deficient (38), human CTLA-4 Ig
transgenic (39), CD28-deficient (40, 41), B7-1/B7-2-double deficient
(42), CD40-deficient (43), CD40L-deficient (44, 45), TNFR I-deficient
(46), TNF--deficient (47), OCA-B deficient (48, 49), and
LT--deficient mice (50, 51, 52). Ag-specific IgG1 titers after TD Ag
immunization were decreased or absent in many of the mutant mice, such
as in MHC class II-deficient, human CTLA-4 Ig transgenic,
CD28-deficient, B7-1/B7-2-deficient, CD40-deficient and CD40L-deficient
mice (38, 39, 40, 41, 42, 43, 44, 45), which are considered to have a defect in T cell-B cell
(T-B) interaction. Furthermore, in human CTLA-4 Ig transgenic mice and
CD28-deficient mice, not only isotype switching but also affinity
maturation following somatic hypermutation were impaired (39, 40, 41). In
other mice described above, affinity maturation was not examined,
although isotype switching was considered to be impaired. In contrast,
LT--deficient mice, which had no lymph nodes (LNs) or Peyer’s
patches and failed to form GCs in the spleen, exhibited normal
Ag-specific IgG1 responses and affinity maturation after TD Ag
immunization (52).
The present study was designed to investigate whether TD
Ag-specific IgG1 responses and affinity maturation could occur in
lyn-/- mice, which are similar to
LT--deficient mice in having a defect in GC formation but which
differ in several B cell abnormalities. The
lyn-/- mice were immunized with
(4-hydroxy-3-nitrophenyl)acetyl-chicken -globulin (NP-CG). The
present study shows that NP-specific IgG1 Abs were slightly reduced but
easily detectable and that the affinity of Abs produced was comparable
to that in wild-type (WT) mice. Since somatic hypermutation also
occurred in the heavy-chain variable region at the same level as in WT
mice, we conclude that isotype switching and affinity maturation occur
normally in lyn-/- mice despite the defect in
ability to form GCs.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Lyn-deficient (lyn-/-) mice (26) of a C57BL/6 background and normal C57BL/6 mice (Clea Japan, Tokoy, Japan) were maintained in our animal facility on a 12-h light/dark cycle.
Immunization of mice and FACS analysis
Mice (4–7 wk old) were immunized i.p. with 100 µg NP-CG absorbed to alum and boosted twice with the same Ag dose at day 21 and 28. NP-CG was a generous gift of Drs. T. Kaisho and K. Rajewsky (Institute for Genetics, University of Cologne, Cologne, Germany). Spleens and LNs were collected 7 days after the final boost (day 35), and cell suspensions derived from both organs were stained with biotin-labeled peanut agglutinin (PNA; Sigma Chemical, St. Louis, MO) and phycoerythrin (PE)-labeled anti-B220 Ab (PharMingen, San Diego, CA). Biotin-labeled PNA was visualized with streptavidin-Red670 (Life Technologies, Gaithersburg, MD). Cells were analyzed using a FACScan (Becton Dickinson, Mountain View, CA) with CELLQuest software.
Measurement of NP-specific Ab
Mice (4–7 wk old) were immunized i.p. with 100 µg NP-CG absorbed to alum and boosted with the same dose of Ag in PBS at day 21. Sera were collected 10 days after primary immunization (day 10) and 7 days after the second immunization (day 28). NP-specific Ab titers were determined by ELISA using microtiter plates coated with NP4-BSA and NP14-BSA (gifts of Drs. T. Kaisho and K. Rajewsky, University of Cologne). NP4-BSA- or NP14-BSA-coated plates were blocked with 1% BSA in PBS, and serially diluted serum samples were added to individual wells. Bound Abs were revealed by a goat anti-mouse IgG1 conjugated with horseradish peroxidase (Southern Biotechnology Associates, Birmingham, AL). NP-specific IgG1 titers were expressed in relative units compared with the hyperimmune mouse serum. (Anti-NP Ab titer of the hyperimmune serum was defined as 100 U.) Both high and low affinity Abs bound to the plate coated with NP14-BSA, whereas only high affinity Abs bound to the plate coated with NP4-BSA. Therefore, the ratio of NP4/NP14-binding Ab titers was used as an index for affinity maturation (52, 53).
RT-PCR for amplification of the VH186.2 gene and sequencing
Mice (4–7 wk old) were immunized i.p. with 100 µg NP-CG
absorbed to alum and boosted twice, using the same Ag dose, at day 21
and day 28. Total RNA was purified from spleens 7 days after the final
boost (day 35) using Isogen (Nippongene, Toyama, Japan). cDNA,
synthesized from 3 µg of total RNA using oligo(dT)-primed reverse
transcription, was used as a template in PCR. The upstream PCR primer
was 5'-CATGCTCTTCTTGGCAGCAACAGC-3'(for VH 186.2),
and the downstream primer was 5'-GTGCACACCGCTGGACAGG GATCC- 3' (for
C1) (52). PCR was performed with Pfu DNA
polymerase (Strategene, La Jolla, CA) for 30 cycles of 1 min at 94°C,
2 min at 55°C, and 3 min at 72°C. The PCR product was cloned into
pCR2.1 (Invitrogen, San Diego, CA) and transformed into DH-5
bacteria. Resultant colonies were randomly picked, and the
VH186.2 gene sequences were obtained by direct plasmid
sequencing using an ABI Prism Sequencing Kit (Perkin-Elmer, Foster
City, CA).
Histology and immunostaining
Mice (6 wk old) were immunized i.p. with 100 µg of NP-CG absorbed to alum. Fourteen days after immunization, spleens were fixed in formalin for 24 h, embedded in paraffin, sectioned at 5 µm, and stained with hematoxylin and eosin. For immunostaining of the tissue sections, mice were immunized i.p. with 100 µg of NP-CG absorbed to alum and boosted twice, using the same Ag dose, at day 21 and day 28. Seven days after the final boost (at day 35), spleens were isolated for frozen sections. The sections were fixed in ethanol containing 5% acetic acid at -20°C for 20 min, blocked in 0.1 M Tris, 0.1 M NaCl, 0.1% Tween 20, 0.1% BSA, and 30% normal rat serum with 200 µg/ml 2.4G2 (a gift of Dr. T. Takemori), and incubated with FITC-labeled anti-B220 Ab (PharMingen) and PE-labeled [(4-hydroxy-5-iodonitrophenyl)acetyl]21-BSA (a kind gift from Dr. T. Takemori, National Institute of Infectious Diseases, Tokyo, Japan) for 2 h at room temperature.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
To confirm the previous report that GCs formed very poorly in
lyn-/- mice (25), we immunized mice (6 wk old)
with NP-CG, a well-characterized TD immunogen (52, 53, 54, 55). In WT mice,
secondary follicles with GC structure were observed in the white pulp
areas after immunization (Fig. 1
,
A and C). In contrast, neither lymphoid
follicles nor GCs could be detected in lyn-/-
mice (Fig. 1, B and D). In addition,
similar results were obtained when mice were immunized with SRBC (data
not shown). Therefore, we concluded that
lyn-/- mice were defective in GC formation.
Since affinity maturation following somatic hypermutation has been
considered to occur within GCs (29, 30, 31, 32), we then investigated whether
this phenomenon could occur in lyn-/-
mice.
|
Before investigating affinity maturation in
lyn-/- mice, we examined whether PNA-positive
B cells were induced after NP immunization, because PNA binds strongly
to B cells in GCs (29). In WT mice, PNAhigh B cells in
spleen were clearly induced after multiple immunizations. Before
immunization, the PNAhigh B cells in total spleen cells was
0.9% (Fig. 2A). After
multiple immunizations with NP-CG, the number of PNAhigh B
cells increased up to 4.3% of total spleen cells (Fig. 2C). In contrast, even after multiple immunizations
with NP-CG, PNAhigh B cells were not significantly
increased in lyn-/- mice, being 0.2% before
immunization and 0.4% after immunization (Fig. 2, B and
D). As described previously, there were 40 to 60%
fewer B220+ cells in the spleen in
lyn-/- mice than in WT mice (25, 26). The
percentage of PNAhigh cells among B220+ B cells
was 0.8% in lyn-/- mice before immunization,
which was comparable to 1.7% in WT mice (Fig. 2A, B). However, while
the PNAhigh B220+ spleen cells increased in WT
mice up to 5.6% after NP immunizations, there was no increase in
lyn-/- mice (1.6%) (Fig. 2, C and
D). Similarly, the mean numbers of
PNAhigh splenic B cells from three WT mice increased after
immunization, whereas the numbers of B cells from three
lyn-/- mice were not increased even after
immunization (Table I). Similar results
were obtained with LN cells (Fig. 3). The
PNAhigh cells among LN B cells also increased from 1.9 to
4.1% in WT mice, whereas there was no increase in
lyn-/- mice (0.9 and 0.7% before and after NP
immunization, respectively). The mean cell numbers of
PNAhigh cells in LN cells from three mice were also similar
to those in spleen cells (Table I). Furthermore, PNAhigh B
cells were not induced 7 days after the single immunization with SRBC
in lyn-/- mice, although they were strongly
induced in WT mice (data not shown). These results indicated that
PNAhigh B cells are not induced in
lyn-/- mice even after multiple immunizations
with NP-CG. The findings are consistent with the results shown in
Figure 1
and with the previous study demonstrating the defect in
ability to form GCs in lyn-/- mice (25).
|
|
|
Since lyn-/- mice have a defect in the
ability to form GCs, we investigated NP-specific IgG1 responses and
affinity maturation, which is considered to occur within GCs (29, 30, 31, 32).
Both WT and lyn-/- mice showed similar serum
IgG1 titers before (25, 26) and after immunization (25), although
lyn-/- mice showed a much higher level of
serum IgM than WT mice (25, 26). The titers of NP-specific IgG1 Abs
were low at day 10 in both WT and lyn-/- mice
(Fig. 4, A and
B), and by day 28, titers of NP14-binding
IgG1 Abs were elevated in WT mice (21.6 ± 22.5 U) (Fig. 4A). In lyn-/- mice,
NP14-binding IgG1 Abs (15.7 ± 15.4 U) were slightly
reduced but readily detectable, indicating that isotype switching
occurred despite the defect in ability to form GCs. The appearance of
NP4-binding Abs indicates affinity maturation. In fact, by
day 28, NP4-binding IgG1 Abs were detectable in WT mice
(24.2 ± 20.3 U) (Fig. 4B). In
lyn-/- mice, NP4-binding Abs
(14.4 ± 18.7 U) were also detectable. Furthermore, the ratio of
NP4-binding/NP14-binding Abs was increased by
day 28 in both WT and lyn-/- mice (0.84
± 0.42 and 0.68 ± 0.32 in WT and lyn-/-
mice, respectively) (Fig. 4C). In addition,
immunostaining using NIP21-BSA showed that NP-specific B
cells did exist in the spleens of both WT and
lyn-/- mice after NP immunizations. As shown
in Figure 5, comparable numbers of
NP-binding B cells were observed in the spleens of
lyn-/- mice and in WT mice, although GC
formation was missing in the lyn-/- mice. We
therefore concluded that Ag-specific IgG1 responses and affinity
maturation occur in lyn-/- mice. The
appearance of high affinity Abs in lyn-/- mice
after boosting demonstrated that generation of memory B cells was not
affected in the absence of Lyn kinase. Thus, affinity maturation,
isotype switching, and generation of memory B cells occur in
lyn-/- mice even without GC formation.
|
|
It has been previously reported that the combination of the heavy
chain variable region gene VH186.2 and the 
1 light
chain predominates during the NP-specific response, and somatic
hypermutation is induced in the VH186.2 gene in the
NP-specific secondary response (31, 34, 52, 54, 55). Since the mutated
VH186.2 gene is highly associated with acquisition of high
affinity to NP, we investigated whether or not VH186.2 IgG1
transcripts expressed in spleen cells from
lyn-/- mice mutated after multiple
immunizations with NP-CG. In WT mice, mutation did not lead to stop
codons and showed a preference for transitions rather than
transversions and a tendency of mutations at AGC/T sequences (Fig. 6 and Table II). These results are consistent with
those previously described (56, 57). In lyn-/-
mice, mutations in the VH186.2 gene showed a similar
pattern, although these mutations did not necessarily prefer
transitions to transversions (Table II). Change of Trp to Leu at codon
33 in the first complementarity-determining region (CDR1) of the
VH186.2 gene results in the acquisition of high affinity
for NP (52, 55). This type of mutation was observed in 14 of 15
independent clones derived from WT mice and in 13 of 15 independent
clones derived from lyn-/- mice (Fig. 6).
Mutation frequency in lyn-/- mice was
comparable to that in WT mice, 5.7 ± 2.3 per clone in WT mice and
5.6 ± 1.8 per clone in lyn-/- mice,
respectively (Table III). If somatic
mutation occurred randomly, the expected R/S (ratio of replacement (R)
to silent (S) mutations) in the CDRs (CDR1 and CDR2) would be 4.9, and
that ratio in the framework regions would be 2.6, as previously
described (54). Elevated ratios of R/S in the CDRs, but not the
framework regions, suggested Ag-driven somatic hypermutation. The R/S
ratio in the framework region was almost equal to what was expected
(3.1 in WT mice and 3.2 in lyn-/- mice) (Table III). In contrast, the ratio in the CDRs was much higher than expected
in both WT and lyn-/- mice (8.0 in WT mice and
11.7 in lyn-/- mice). We concluded, therefore,
that Ag-induced somatic hypermutation occurs in
lyn-/- mice and that
lyn-/- mice are able to undergo affinity
maturation and memory B cell generation.
|
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Several possibilities might be considered to explain the defect
in GC formation in lyn-/- mice. 1)
Lyn-/- mice may be disrupted in T-B
interaction. 2) Lyn-/- mice may have some
abnormalities in cells supporting GC formation such as interdigitating
dendritic cells (28) or follicular dendritic cells (FDCs) (58, 59). 3)
Lyn-/- mice may have difficulty in forming B
cell follicles because of reduced numbers of circulating B cells and
insufficient expansion in response to CD40 signal. 4) Lyn kinase may
play a role in the homing capacity of B cells to secondary lymphoid
organs. In contrast to mutant mice with a disruption in T-B
interaction, such as CD40-deficient or B7-1/B7-2-deficient mice (42, 43), which fail to form GCs, lyn-/- mice
responded normally to TD Ags, indicating that T-B interaction may not
be impaired by the Lyn defect. Th cells and interdigitating dendritic
cells play an important role in the activation of B cells in T
cell-rich zones of the periarteriolar lymphatic sheath (PALS) in the
splenic white pulp (28). Lyn kinase may be associated with the function
of interdigitating dendritic cells, although Lyn has never been
reported to play any role in dendritic cells. FDCs in primary and
secondary B cell follicles can retain unprocessed Ag on their surface
in the form of immune complexes for several months, and may play an
important role in positive selection of the centrocytes with high
affinity for Ag (28). FDCs are reported to form the clusters through
interaction between ICAM-1 on FDCs and LFA-1 on B cells. VLA-4 on
activated B cells supports B cell-FDC cluster formation by binding to
VCAM on FDCs (52). Organized FDC structure, such as FDC-B cell
clusters, was reportedly absent in LT--deficient mice in which GCs
were absent but affinity maturation occurred normally (52).
Lyn-/- mice may also exhibit some
abnormalities in the function or structure of FDCs, although Lyn kinase
has not been reported to be associated with the function of FDCs or
interdigitating dendritic cells. The numbers of peripheral B cells in
lyn-/- mice are 40 to 60% less than that in
WT mice (25, 26). In addition, splenic B cells in
lyn-/- mice show a reduced proliferative
response to CD40L (26, 27). The combination of small numbers of B cells
and the defect in ability to expand in response to CD40 signaling might
cause a lack of B cell follicles in lyn-/-
mice. Therefore, PNAhigh B cells may not be induced and GCs
may not be formed in lyn-/- mice. Since
splenic B cells of lyn-/- mice could not make
complexes nor form follicles in the white pulp, Lyn kinase may be
associated with homing or adhesion to B cell follicles. However, Lyn
has not been demonstrated to be downstream of adhesion
molecule-mediated signaling, and homing abnormalities of B cells have
not been detected in lyn-/- mice. Thus,
although lyn-/- mice showed defective
formation of B cell follicles and GCs, the molecular mechanism for the
deficiency is still unclear.
lyn-/- mice displayed normal isotype switching and affinity maturation despite the defect in GC formation. It has been reported that Lyn kinase is activated by CD40 ligation (15), and splenic B cells of lyn-/- mice showed reduced proliferative responses to CD40L and reduced susceptibility to Fas-mediated apoptosis through CD40 (26, 27). These results suggested that Lyn might be involved in signal transduction from CD40. Previous studies reported that CD40-deficient and CD40L-deficient mice failed to form GCs and did not produce Ag-specific IgG1, indicating a crucial role of CD40 signaling in isotype switching(43, 44, 45). Thus, there is a discrepancy between the results in lyn-/- mice and those in CD40-deficient or CD40L-deficient mice concerning isotype switching despite the absence of GC formation in both cases. In addition, although CD40-CD40L signal was considered essential for affinity maturation following somatic hypermutation (36), lyn-/- mice showed a normal response. The explanation for the discrepancy may be that CD40-mediated signaling consist of two pathways, only one of which is Lyn dependent (26). It is possible that isotype switching and affinity maturation following somatic hypermutation are induced by the Lyn-independent CD40-mediated signal pathway. This possibility explains why lyn-/- mice showed normal Ag-specific IgG1 isotype switching and affinity maturation. Alternatively, other Src family kinases may compensate for the lack of functional Lyn, but this is unlikely because Lyn/Fyn doubly deficient mice also showed a defect similar to that of lyn-/- mice (Nishizumi et al., unpublished observations).
Why do isotype switching and affinity maturation occur in
lyn-/- mice despite the lack of GC formation?
One explanation may be that although typical GCs were absent in both
spleen and LN, small numbers of abnormally located PNA+ B
cells were present in either or both organs, and those cells could
induce isotype switching and affinity maturation without formation of
any GC structure. This explanation is consistent with previous studies
demonstrating that PNA+ B cells themselves can internalize
immunogen and present it to T cells in vivo, while a bulk population of
B cells containing few PNA+ cells and a majority of
PNA- cells could not present the immunizing Ag to T cells
(58, 60). This possibility, however, is unlikely, since the number of
PNA+ B cells greatly decreased in the spleens and LNs in
lyn-/- mice. Another explanation may be that
Lyn kinase-deficient B cells could not express receptors for PNA, but
these PNA-negative B cells still function in the GC reaction by
internalizing immunogen and presenting it to T cells. Thus, PNA
expression may have nothing to do with the function of B cells in GCs.
Alternatively, isotype switching and affinity maturation may be
independent of GC formation or the appearance of PNA+ B
cells, but these functions may be dependent on establishing an
environment in which cross-interaction between T cells, B cell and
dendritic cells can take place. At least, the significance of the GC
architecture itself should be reconsidered, since isotype switching,
affinity maturation, and differentiation to B cell memory clearly can
occur without GC structure in both LT--deficient mice and
Lyn-deficient mice. Lyn-/- mice may provide a
good model for elucidating the physiologic significance of
GCs.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
2 Abbreviations used in this paper: BCR, B cell antigen receptor; sIgM, surface IgM; PTK, protein tyrosine kinase; PLC, phospholipase C; PI-3, phosphatidylinositol-3; CD40L, CD40 ligand; GC, germinal center; TD, thymus-dependent; T-B, T cell-B cell; NP-CG, (4-hydroxy-3-nitrophenyl)acetyl-chicken -globulin; WT, wild-type; LN, lymph node; PNA, peanut agglutinin; CDR, complementarity-determining region; FDC, follicular dendritic cell; PE, phycoerythrin.
Received for publication August 18, 1997. Accepted for publication January 21, 1998.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
2 in B lymphocytes. Proc. Natl. Acad. Sci. USA 89:5660.2. J. Exp. Med. 179:673.1: lack of germinal centers correlated with poor affinity maturation and class switching. J. Exp. Med. 179:819.-deficient mice: a critical requirement for TNF in the formation of primary B cell follicles, follicular dendritic cell network and germinal centers and in the maturation of the humoral immune response. J. Exp. Med. 184:1397.. Science 264:703.-deficient mice: effects on secondary lymphoid organ development and humoral immune responsiveness. J. Immunol. 155:1685.[Abstract]
-deficient mice. Nature 382:462.[Medline]
This article has been cited by other articles:
|
|
 |
|
  L. Quemeneur, V. Angeli, M. Chopin, and R. Jessberger SWAP-70 deficiency causes high-affinity plasma cell generation despite impaired germinal center formation Blood, March 1, 2008; 111(5): 2714 - 2724. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Yang, G. C. Waldbieser, and C. J. Lobb The Nucleotide Targets of Somatic Mutation and the Role of Selection in Immunoglobulin Heavy Chains of a Teleost Fish J. Immunol., February 1, 2006; 176(3): 1655 - 1667. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. K. Mirnics, E. Caudell, Y. Gao, K. Kuwahara, N. Sakaguchi, T. Kurosaki, J. Burnside, K. Mirnics, and S. J. Corey Microarray Analysis of Lyn-Deficient B Cells Reveals Germinal Center-Associated Nuclear Protein and Other Genes Associated with the Lymphoid Germinal Center J. Immunol., April 1, 2004; 172(7): 4133 - 4141. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Inui, K. Maeda, D. R. Hua, T. Yamashita, H. Yamamoto, E. Miyamoto, S. Aizawa, and N. Sakaguchi BCR signal through {alpha}4 is involved in S6 kinase activation and required for B cell maturation including isotype switching and V region somatic hypermutation Int. Immunol., February 1, 2002; 14(2): 177 - 187. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Alfonso, J.-O. Han, G. S. Williams, and L. Karlsson The Impact of H2-DM on Humoral Immune Responses J. Immunol., December 1, 2001; 167(11): 6348 - 6355. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Driver, L. J. McHeyzer-Williams, M. Cool, D. B. Stetson, and M. G. McHeyzer-Williams Development and Maintenance of a B220- Memory B Cell Compartment J. Immunol., August 1, 2001; 167(3): 1393 - 1405. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S.-j. Seo, J. Buckler, and J. Erikson Novel Roles for Lyn in B Cell Migration and Lipopolysaccharide Responsiveness Revealed Using Anti-Double-Stranded DNA Ig Transgenic Mice J. Immunol., March 15, 2001; 166(6): 3710 - 3716. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Brauninger, W. Yang, H.-H. Wacker, K. Rajewsky, R. Kuppers, and M.-L. Hansmann B-cell development in progressively transformed germinal centers: similarities and differences compared with classical germinal centers and lymphocyte-predominant Hodgkin disease Blood, February 1, 2001; 97(3): 714 - 719. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Wu, N. Jiang, Y.-F. Fang, C. Xu, D. Mao, J. Singh, Y.-X. Fu, and H. Molina Impaired Affinity Maturation in Cr2-/- Mice Is Rescued by Adjuvants Without Improvement in Germinal Center Development J. Immunol., September 15, 2000; 165(6): 3119 - 3127. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Uchida, T. Yasui, Y. Takaoka-Shichijo, M. Muraoka, W. Kulwichit, N. Raab-Traub, and H. Kikutani Mimicry of CD40 Signals by Epstein-Barr Virus LMP1 in B Lymphocyte Responses Science, October 8, 1999; 286(5438): 300 - 303. [Abstract] [Full Text]
|
|
|
|
|
|
A. R. Thompsett, D. W. Ellison, F. K. Stevenson, and D. Zhu VH Gene Sequences From Primary Central Nervous System Lymphomas Indicate Derivation From Highly Mutated Germinal Center B Cells With Ongoing Mutational Activity Blood, September 1, 1999; 94(5): 1738 - 1746. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. HogenEsch, S. Janke, D. Boggess, and J. P. Sundberg Absence of Peyer's Patches and Abnormal Lymphoid Architecture in Chronic Proliferative Dermatitis (cpdm/cpdm) Mice J. Immunol., April 1, 1999; 162(7): 3890 - 3896. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. A. Koni and R. A. Flavell Lymph Node Germinal Centers Form in the Absence of Follicular Dendritic Cell Networks J. Exp. Med., March 1, 1999; 189(5): 855 - 864. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A N Theofilopoulos Effector and predisposing genes in murine lupus Lupus, November 1, 1998; 7(9): 575 - 584. [Abstract] [PDF]
|
|
|
|
 |
|
 J. Tan, T. Town, and M. Mullan CD45 Inhibits CD40L-induced Microglial Activation via Negative Regulation of the Src/p44/42 MAPK Pathway J. Biol. Chem., November 17, 2000; 275(47): 37224 - 37231. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
