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The Journal of Immunology, 2004, 173: 2245-2252.
Copyright © 2004 by The American Association of Immunologists

TNF Family Member B Cell-Activating Factor (BAFF) Receptor-Dependent and -Independent Roles for BAFF in B Cell Physiology1

Yoshiteru Sasaki2,*, Stefano Casola*, Jeffery L. Kutok{dagger}, Klaus Rajewsky* and Marc Schmidt-Supprian2,*

* CBR Institute for Biomedical Research, Harvard Medical School, Boston, MA 02115; and {dagger} Department of Pathology, Brigham and Women’s Hospital, Boston, MA 02115


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
The cytokine TNF family member B cell-activating factor (BAFF; also termed BLyS) is essential for B cell generation and maintenance. Three receptors have been identified that bind to BAFF: transmembrane activator, calcium modulator, and cyclophilin ligand interactor (TACI); B cell maturation Ag (BCMA); and BAFF-R. Recently, it was shown that A/WySnJ mice, which contain a dramatically reduced peripheral B cell compartment due to decreased B cell life span, express a mutant BAFF-R. This finding, together with normal or enhanced B cell generation in mice deficient for BCMA or TACI, respectively, suggested that the interaction of BAFF with BAFF-R triggers signals essential for the generation and maintenance of mature B cells. However, B cells in mice deficient for BAFF differ phenotypically and functionally from A/WySnJ B cells. Residual signaling through the mutant BAFF-R could account for these differences. Alternatively, dominant-negative interference by the mutant receptor could lead to an overestimation of the importance of BAFF-R. To resolve this issue, we generated BAFF-R-null mice. Baff-r–/– mice display strongly reduced late transitional and follicular B cell numbers and are essentially devoid of marginal zone B cells. Overexpression of Bcl-2 rescues mature B cell development in Baff-r–/– mice, suggesting that BAFF-R mediates a survival signal. CD21 and CD23 surface expression are reduced on mature Baff-r–/– B cells, but not to the same extent as on mature B cells in BAFF-deficient mice. In addition, we found that Baff-r–/– mice mount significant, but reduced, Ag-specific Ab responses and are able to form spontaneous germinal centers in mesenteric lymph nodes. The reduction in Ab titers correlates with the reduced B cell numbers in the mutant mice.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
The TNF family member B cell-activating factor (BAFF,3 also known as BLyS, TALL-1, zTNF4, or THANK) is required for generation and maintenance of the mature B cell pool. BAFF is expressed on a variety of cells of myeloid and other origin, and its expression pattern may control the compartmentalization of B cells in the peripheral immune system, such as the localization of B cells to B cell follicles (1, 2, 3, 4, 5). Newly formed B cells in the bone marrow (BM) reach the spleen as transitional type 1 (T1) B cells. These cells subsequently develop into transitional type 2 (T2), transitional type 3 (T3), and into the mature follicular and marginal zone (MZ) B cells (6, 7). BAFF promotes the survival of T2, T3, and mature B cells (8, 9, 10). Genetic disruption of the Baff gene leads to a profound defect in mature B2 and MZ B cells, whereas B1 B cells are not affected. This was initially attributed to a complete block of B cell development at the T1 stage (11, 12). However, later analyses showed that some mature B cells can be generated in the absence of BAFF (13, 14). These B cells lack expression of the CD21 and CD23 surface markers, suggesting that expression of these receptors depends on BAFF (14). B cells are recruited into germinal centers (GC) upon Ag stimulation in the absence of BAFF, albeit in a transient fashion (13, 15).

In contrast, transgenic mice engineered to overexpress BAFF show increased numbers of peripheral B cells and elevated serum Ig levels, including anti-DNA Abs, rheumatoid factor, and circulating immune complexes, and develop autoimmune symptoms resembling human systemic lupus erythematosus and Sjögren’s syndrome as they age. Elevated serum BAFF levels have been detected in patients with rheumatoid arthritis, systemic lupus erythematosus, and Sjögren’s syndrome (1, 2, 3, 4, 5).

BAFF can bind to three receptors of the TNFR family: transmembrane activator, calcium modulator, and cyclophilin ligand interactor (TACI); B cell maturation Ag (BCMA); and BAFF-R (also known as BLyS receptor 3 or BR3). TACI and BMCA also bind to another TNF family member, a proliferation-inducing ligand (1, 2, 3, 4, 5). A proliferation-inducing ligand, BCMA, and TACI are all dispensable for B cell development (16, 17, 18, 19, 20), indicating that triggering of BAFF-R by BAFF is essential for the generation of mature B cells. A/WySnJ mice contain 10% of the peripheral B cells found in control A/J mice, due to a reduced life span of B2, but not of B1 cells (21, 22, 23, 24). These mice harbor a transposon insertion that replaces the last 8 aa of the C terminus of BAFF-R with 21 aa encoded by the insertion (25, 26). The mutant receptor is expressed on the surface of A/WySnJ B cells and is capable of binding BAFF (27), suggesting that its signaling capacities are impaired. This notion is supported by the fact that BAFF administration increases B cell numbers in A/J, but not in A/WySnJ mice (24). However, significant differences exist between A/WySnJ and Baff–/– mice; A/WySnJ mice, in constrast to Baff–/– mice, contain CD21- and CD23-expressing follicular and CD21highCD23low MZ B cells (12, 26). They exhibit IgM serum levels comparable to A/J mice (28), whereas in Baff–/– mice IgM levels in the blood are strongly reduced (12). A/WySnJ mice mount efficient IgM responses against T-dependent (TD) and T-independent (TI) Ags, but are profoundly deficient in producing primary or secondary IgG responses (28). The Ag-specific Ab production by Baff–/– mice in response to TD and TI Ags, in contrast, is dramatically reduced compared with wild-type mice, suggesting that production of all Ig subclasses is affected (12).

The differences observed in B cell phenotypes and function between A/WySnJ and Baff–/– mice can be explained by the nature of the A/WySnJ mutation, which leaves most of the BAFF-R intact. The mutant receptor could therefore retain some signaling functions. Alternatively, it could heterotrimerize with other TNF-R-like molecules, such as BCMA or TACI, and act as a dominant-negative molecule. Therefore, B cell physiology could be affected more by expression of a mutant BAFF-R, than by lack of the receptor, leading to an overinterpretation of the role of BAFF-R. However, it is also possible that BAFF exerts some of its functions through its other receptors, BCMA and TACI, or in a non-B cell-autonomous fashion through as yet unidentified receptors.

To more precisely define the role of BAFF-R in B cell development, we generated mice that are deficient for this receptor. Baff-r–/– mice demonstrate a block in B cell development at the transitional stage. The mutant mice show a 40-fold reduction in numbers of mature B2 cells and contain very few, if any, MZ B cells. Baff-r–/– B cells produce reduced, but significant Ag-specific Ab titers in response to immunizations with TI and TD Ags, and they develop into GC B cells in mesenteric lymph nodes (mLNs) in response to gut-derived Ags. The main function of BAFF-R appears to provide a survival signal to mature B cells, as overexpression of Bcl-2 rescues mature B cell development in Baff-r–/– mice.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Generation of Baff-r–/– mice and maintenance of mice

Construction of a conditional Baff-rFL targeting vector. An EcoRI fragment of the mouse Baff-r genomic locus in pBluescript II was used. The targeting vector was designed to flank exons 3 and 4 of the Baff-r gene with two loxP sites. An frt site-flanked selection cassette, containing a neor gene and the Flpe6 cDNA cloned under control of the ACE promoter (29), was placed into the fourth intron of the Baff-r gene. A 1.9-kb AvrII-MfeI fragment was used as 5' homology region, a 1.3-kb MfeI-AvrII fragment was placed between the two loxP sites, and a 5.0-kb AvrII-BamHI fragment was used as 3' homology region. A thymidine kinase gene was used for negative selection of clones with random integration of the targeting vector.

Bruce-4 embryonic stem (ES) cells (30) derived from C57BL/6 mice were transfected, cultured, and selected, as previously described (31). Of 475 G418 and gancyclovir-resistant colonies, 2 were identified as homologous recombinants with cointegration of the second loxP site by Southern blot analysis of BglII-digested DNA, using a 465-bp fragment as 5' external probe (Fig. 1). Mice were bred and maintained in specific pathogen-free conditions; all mouse protocols were approved by the Harvard University Institutional Animal Care and Use Committee and by the CBR Institute for Biomedical Research. The Eµ-bcl-2-22 (32) transgenic mouse strain was obtained from The Jackson Laboratory (Bar Harbor, ME).



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  		FIGURE 1. Generation of BAFF-R-deficient mice. A, Schematic representation of the targeting strategy. a, Structure of Baff-r cDNA. b, Sketch of the Baff-r genomic locus. c, The targeting construct was designed to flank exons 3 and 4 by two loxP sites (triangles) and a Neor casette by two frt sites (ovals). d, The targeted allele. The probe used for Southern blot analysis is shown as a bar. e, The structure of the Baff-r– allele. B, Southern blot analysis of targeted ES clones. Genomic DNA from wild-type (lane 1) and two targeted ES clones (lanes 2 and 3) was digested with BglII and probed with the external probe shown in Ad. C, Southern blot analysis of tail DNA of Baff-r–/– mice. DNA was digested with BglII (left panel) or SacI (right panel) and hybridized with the probe shown in Ad. D, RT-PCR analysis to detect expression of Baff-r in spleen. HPRT expression is shown as control. E, FACS analysis of BAFF-R expression on the surface of B220+ splenocytes using rabbit anti-BAFF-R serum. +/+, +/–, and –/–, Wild-type, heterozygous, and homozygous BAFF-R knockout mice, respectively. The shaded histogram (control) shows staining with preimmune rabbit serum.

 
RT-PCR analysis

Total RNA was extracted from splenocytes with TRIzol (Invitrogen Life Technologies, Carlsbad, CA), according to the manufacturer’s protocol. One microgram of total RNA was used for first-strand cDNA synthesis with random hexamer primers and Superscript RT III (Invitrogen Life Technologies). Baff-r and Hprt (hypoxanthine phosphoribosyltransferase) cDNA was amplified by PCR with the following intron-spanning primers: BAFF-R-1, 5'-CCCAGACTCGGAACTGTCCC-3'; BAFF-R-2, 5'-GTAGAGATCCCTGGGTTCCAG-3'; Hprt-1, 5'-ATTAGCGATGATGAACCAGGTTA-3'; Hprt-2, 5'-CCAGTTAAAGTTGAGATCATCTCCAC-3'. PCR conditions were as follows: 94°C for 30 s, 58°C for 30 s, and 72°C for 30 s for 40 cycles with 1 U of KOD HiFi polymerase (Novagen, Madison, WI).

Flow cytometry

Single-cell suspensions prepared from various lymphoid organs and the peritoneum were stained with the following mAbs conjugated to FITC, PE, CyChrome, allophycocyanin, or biotin: anti-CD5 (53-7.3), anti-CD19 (ID3), anti-CD21 (7G6), anti-CD23 (B3B4), anti-CD38 (90), anti-CD1d (1B1), anti-Fas (Jo2), anti-IgD (11-26c.2a) (all from BD Pharmingen, San Diego, CA), and anti-AA4.1 (eBioscience, San Diego, CA). Additional, "homemade" mAbs to IgM (R33-2412) and B220 (RA3-6B2) were used. Rabbit polyclonal Abs to mouse BAFF-R were generated by immunization with a synthesized mouse BAFF-R peptide (aa 1–17). PNA conjugates were PNA-FITC and PNA-biotin (Vector Laboratories, Burlingame, CA). Biotin conjugates were visualized with CyChrome or allophycocyanin (BD Pharmingen). Anti-BAFF-R Ab was visualized with goat anti-rabbit IgG FITC (Zymed Laboratories, San Francisco, CA). All samples were acquired on a FACSCalibur (BD Pharmingen), and results were analyzed with CellQuest software.

Immunohistochemistry

For staining of B cells and macrophages, frozen 6-µm sections were thawed, air dried, fixed in acetone, and stained for 1 h at room temperature in a humidified chamber with biotinylated rat anti-CD19 (BD Pharmingen) and rat anti-MOMA-1 (Cedarlane Laboratories, Hornby, Canada), followed by HRP-conjugated goat anti-rat IgG and alkaline phosphatase-conjugated streptavidin. For staining of B and T cells, sections were stained for 1 h at room temperature in a humidified chamber with biotinylated anti-CD19 and armenian hamster anti-CD3{epsilon} (eBioscience). Bcl-6 expression was detected with a rabbit anti-Bcl-6 (Santa Cruz Biotechnology, Santa Cruz, CA), followed by incubation with HRP-conjugated goat anti-rabbit IgG (DakoCytomation, Carpinteria, CA).

Immunization and serum analyses

Mice were immunized with 100 µg of TD Ag 4-hydroxy-3-nitrophenylacetyl chicken {gamma}-globulin (NP-CG) in alum i.p. Mice were boosted with 10 µg of NP-CG without adjuvant on day 48. TI immune responses were elicited by i.p. injections of 50 µg of NP-Ficoll. Mice were bled before and after immunization from tail veins. Ig serum concentrations were determined by ELISA, as described previously (33).


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Generation of BAFF-R-deficient mice

To study the physiological role of BAFF-R in vivo, we generated BAFF-R-deficient mice by gene targeting. The targeting vector was designed to place exons 3 and 4, which encode the entire extracellular and transmembrane domains and part of the cytoplasmic domain, between loxP sites (Fig. 1A). Two C57BL/6-derived ES clones (30) with the appropriately targeted allele were obtained (Fig. 1B), injected into BALB/c blastocysts to generate chimeric mice, which transmitted the targeted loxP-flanked Baff-r allele (Baff-rFL) to their progeny (Fig. 1C). All mice were maintained on a pure C57BL/6 genetic background. The frt-flanked neor casette can be removed through intercrossing with Flpe-deleter mice (34). To obtain a Baff-r null allele (Baff-r–), Baff-rFL/+ mice were crossed with the deleter strain (35) (Fig. 1C). The expression of BAFF-R in BAFF-R-deficient mice (Baff-r–/–) was examined both at the RNA and the protein level. No Baff-r mRNA could be detected by RT-PCR analysis in Baff-r–/– mice (Fig. 1D). FACS analysis using a polyclonal anti-BAFF-R Ab revealed absence of BAFF-R expression on the surface of B220+ Baff-r–/– splenic cells (Fig. 1E). Despite the reduction of BAFF-R surface levels on Baff-r+/– B cells (Fig. 1E), we did not detect any statistically significant differences in B cell development in our analyses between Baff-r+/– and wild-type mice, which are therefore collectively referred to as control mice below.

Decreased numbers of mature B cells in Baff-r–/– mice

B cell development in Baff-r–/– mice was examined by flow cytometric analyses. In the BM of Baff-r–/– mice, early B cell development was essentially normal. The only difference between BM B cells of control and Baff-r–/– mice was a strong reduction of mature recirculating B cells in the latter (Fig. 2A). The fraction of IgD-positive B cells was >10-fold reduced in Baff-r–/– BM compared with control mice (data not shown). In the spleen, B cell numbers were strongly reduced (Table I). The reduction occurred mainly in the IgMlowIgD+ mature B cell subset (Fig. 2B). Immunohistological staining of spleen sections revealed small CD19+ B cell clusters, but essentially normal-sized CD3+ T cell areas in Baff-r–/– mice (Fig. 3A). Lymph nodes (LNs) of Baff-r–/– mice also had a >20-fold reduced IgMlowIgD+ mature B cell fraction (Fig. 2C). Accordingly, few and very small B cell clusters were detected in LNs from Baff-r–/– in comparison with control mice (Fig. 3C). In the peritoneal cavity of the mutants, the B220highCD19intemediate B2 cell population was reduced >10-fold, but the CD19highB220low B1 cell population was not affected (Fig. 2D, upper panels). The ratio of B1a (CD5+) to B1b (CD5–) cells was also normal in Baff-r–/– mice (Fig. 2D, lower panels). Analysis of T cell development in Baff-r–/– mice yielded normal numbers of conventional peripheral CD4 and CD8 T cells. The generation of memory-type T cells, regulatory CD4+CD25+ T cells, and NK-like T cells was also not affected by the absence of BAFF-R (data not shown).



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  		FIGURE 2. Flow cytometric analysis of B cell population in Baff-r–/– mice. A, Comparison of BM B cells from wild-type, Baff-r+/–, and Baff-r–/– mice. B, Analysis of splenocytes for the surface expression of IgM and IgD. C, Analysis of LN lymphocytes for the surface expression of IgM and IgD. D, Analysis of B cell subpopulations in the peritoneal cavity (PC). B2 cells are B220highCD19low, and B1 cells are B220lowCD19high. B1a cells are CD5+, whereas B1b cells are CD5low. The numbers refer to the percentages of cells in individual gates of total live lymphocytes, or of cells in the gate indicated in brackets above the dot plots.

 

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  		Table I. Number of splenic B cell populations in Baff-r+/+, Baff-r+/–, and Baff-r–/– micea

 


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  		FIGURE 3. Histological analysis of spleen and LN from wild-type, Baff-r+/–, and Baff-r–/– mice. A, Anti-CD19 (blue) and anti-CD3 (red) staining of spleen sections. The upper panels are shown in 100-fold magnification, and the lower panels in 200-fold magnification. B, Anti-CD19 (blue) and anti-MOMA-1 (red) staining of spleen sections. Magnification of the upper panels is x100, and that of the lower panels is x200. C, Anti-CD19 (blue) and anti-CD3 (red) staining of LN sections. Magnification is x200.

 
B cell maturation is blocked at the transitional stages in Baff-r–/– mice

Newly formed or immature B cells emigrate from the BM, reach the spleen as so-called transitional B cells, and subsequently mature into follicular and MZ B cells. Transitional B cells can be subdivided into three distinct subsets (T1–3) according to the surface expression of AA4.1 (CD93, C1qRp), IgM, and CD23 (36). This staining procedure offers the advantage that B1 cells can be separated from the transitional subsets, which is not possible by using the surface markers IgM and IgD or CD21 and CD23 for B cell subpopulation analysis. Only transitional stage B cells express AA4.1, whereas mature B cells do not. In spleens from Baff-r–/– mice, the majority of B220+ cells are AA4.1+ transitional B cells (Fig. 4A and Table I). Further analysis of the transitional stages showed that in Baff-r–/– mice, the sizes of the T2 (IgM+CD23+) and T3 (IgMlowCD23+) populations were reduced, whereas the proportion of T1 B cells (IgM+CD23–) was increased (Fig. 4B and Table I). Absolute T1 B cell numbers were comparable to those of control mice (Table I). Recently, it was reported that the surface expression of CD23 is regulated by BAFF (14). Therefore, the use of CD23 as a B cell maturation marker is problematic in Baff-r–/– mice. However, analysis of IgM expression levels on AA4.1+ Baff-r–/– and control B cells confirmed a developmental block in B cell development from IgM+ cells (T1 + T2) to IgMlow cells (T3) (Fig. 4C). Analysis of CD23 expression on AA4.1– mature B cells revealed two populations, one with low CD23 expression and one with CD23 expression comparable to control B cells (Fig. 4D). This indicates that some B cells can express CD23 in the absence of BAFF-R signaling. MZ B cells are usually defined as CD19+CD21highCD23low populations (37). However, because the expression of both CD21 and CD23 is regulated by BAFF (14), we assessed MZ B cell development in Baff-r–/– mice by using the cell surface markers CD1d and CD38, known to be expressed at higher levels on MZ than on follicular B cells (37, 38). This analysis demonstrated that MZ B cells are essentially absent in Baff-r–/– mice (Fig. 4E and Table I). We confirmed this finding by immunohistological staining of spleen sections with the B cell marker CD19 and the metallophilic macrophage marker MOMA-1. This staining showed little, if any, B cells in the MZ area of spleen sections of Baff-r–/– in contrast to control mice (Fig. 3B).



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  		FIGURE 4. Flow cytometric analysis of B cell subpopulations in the spleen. A, Analysis of splenocytes for surface expression of AA4.1 and B220. Transitional B cells are AA4.1+, and mature B cells are AA4.1–. B, Analysis of B220+AA4.1+ transitional B cells for surface expression of IgM and CD23; T1, IgM+CD23–; T2, IgM+CD23+; T3, IgMlowCD23+. C, Histogram of IgM expression on B220+AA4.1+ transitional B cells: T1, T2, IgM+; T3, IgMlow. D, Histogram of CD23 expression on B220+AA4.1– mature B cells. E, Analysis of surface expression of CD1d (upper panel) and CD38 (lower panel) on splenic B cells. The numbers refer to the percentages of cells in individual gates of total live lymphocytes, or of cells in the gate indicated in brackets above the dot plots.

 
Baff-r–/– mice mount reduced Ag-specific Ab responses

Measurement of Ig isotype levels in the blood of unimmunized mice revealed decreased titers of IgM, IgG1, IgG2a, IgG2b, and IgG3 in Baff-r–/– compared with control mice (Fig. 5A). In contrast, the serum concentration of IgA was similar in Baff-r–/– and control mice, most likely reflecting normal numbers of B1 cells in Baff-r–/– mice (39).



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  		FIGURE 5. Serum Ig titers and the humoral immune response to a TI-II Ag in wild-type (green circles), Baff-r+/– (blue circles), and Baff-r–/– (red circles) mice. The bars indicates geometric means. A, Titers of Ig isotypes in the serum of unimmunized mice (n = 5–8). B and C, Immune responses to NP-Ficoll (wild type, n = 3; Baff-r+/–, n = 4; Baff-r–/–, n = 3). NP-specific IgM (B) and IgG3 (C) in sera of mice after immunization with 50 µg of NP-Ficoll are shown.

 
To determine whether Baff-r–/– mice can respond to TI and TD Ags, we immunized mice i.p. with NP-Ficoll, a TI type II Ag (TI-II), or with NP-CG, a TD Ag. Monitoring of the TI-II humoral immune responses at different time points after immunization with NP-Ficoll revealed that Baff-r–/– mice produced lower titers of NP-specific IgM and IgG3 than control mice (Fig. 5, B and C). Determination of TD responses by measuring NP-specific Ab titers at different time points after immunization with saturating doses of NP-CG showed that Baff-r–/– mice produced only slightly lower levels of NP-specific IgM than control mice. However, the NP-specific IgG1 response was significantly reduced in Baff-r–/– compared with control mice (Fig. 6). Forty-eight days after the primary immunization, we immunized all mice with a second dose of NP-CG without adjuvant to evaluate the secondary Ab response. Baff-r–/– mice mounted a secondary response of NP-specific IgM similar to that of control mice. However, we could not detect a secondary NP-specific IgG1 response in Baff-r–/– mice (Fig. 6).



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  		FIGURE 6. The humoral immune response to a TD Ag in wild-type (green circles, n = 4), Baff-r+/– (blue circles, n = 3), and Baff-r–/– (red circles, n = 3) mice. The serum titers of NP-specific IgM (A) and IgG1s (B) in primary and secondary responses after initial immunization with 100 µg and subsequent boost immunization with 10 µg of NP-CG are shown.

 
GCs are formed in mLNs of Baff-r–/– mice

In mLNs, spontaneous GCs occur in response to gut-derived bacterial Ags (40, 41). Because GC formation can be initiated, but not maintained, in Baff–/– and A/WySnJ mice (13, 15), we analyzed GC B formation in mLNs of Baff-r–/– and control mice by flow cytometry. This analysis revealed that B cells in the mLNs of Baff-r–/– mice can continuously differentiate into FashighPNAhigh GC B cells, presumably in response to microbial Ags derived from the gut (Fig. 7A). Histological analysis of mLN confirmed the presence of GC B cells expressing high levels of the transcription factor Bcl-6 in Baff-r–/– mice.



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  		FIGURE 7. Analysis of GC B cells in mLNs. A, Flow cytometric analysis of lymphocytes from mLNs for the surface expression of Fas and PNA. The numbers refer to the percentages of CD19+ cells of total live lymphocytes. B, Histological analysis of GC in mLNs from wild-type, Baff-r+/–, and Baff-r–/– mice; anti-CD19 (blue) and anti-Bcl-6 (red) stainings of mLN sections are shown. Magnification is x400.

 
Overexpression of the antiapoptotic protein Bcl-2 rescues the development of mature B cells in Baff-r–/– mice

BAFF is considered to be a B cell survival factor (2). The fact that Baff–/– and Baff-r–/– mice display a similar reduction in B cell numbers (Ref.12 and this study) suggests that BAFF-R is indeed the receptor through which BAFF exerts its antiapoptotic effects. BAFF treatment was shown to increase the levels of the antiapoptotic proteins Bcl-xL, Bcl-2, and A1 in B cells (9, 42, 43, 44, 45). We addressed this issue by attempting to rescue B cell development in BAFF-R-deficient mice by overexpression of the antiapoptotic protein Bcl-2. This was achieved through intercrossing Baff-r–/– mice with Eµ-bcl-2 transgenic mice, which express Bcl-2 in B cells (32). FACS analysis revealed that overexpression of Bcl-2 restored the mature IgD+IgMlow and B220+AA4.1– B cell compartments in the compound mutants to a similar size as in control Baff-r+/–/Eµ-bcl-2 mice (Fig. 8, A and B). However, mature Baff-r–/–/Eµ-bcl-2 B cells expressed lower levels of CD21 than control B cells (Fig. 8C), indicating that the regulation of CD21 by BAFF-R is independent of its prosurvival function.



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  		FIGURE 8. Flow cytometric analysis of B cell population in spleen of Baff-r–/–/Eµ-bcl-2 and control mice. A and B, Surface expression of IgM and IgD (A), and of AA4.1 and B220 (B). C, Surface expression of CD21 and CD23 on CD19+ splenocytes. The numbers refer to the percentages of cells in individual gates of total live lymphocytes, or of cells in the gate indicated in brackets above the dot plots.

 

   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
The TNF family member BAFF, which plays a critical role in the development of B2 and MZ B cells, binds to three receptors: BCMA, TACI, and BAFF-R. Ablation of BAFF-R results in a very strong reduction of mature B2 cell numbers, leaving the B1 compartment unaffected, essentially recapitulating the phenotype of Baff–/– and A/WySnJ mice (11, 12, 23). This deficiency in mature B cells is due to a survival defect caused by absence of BAFF-R, because overexpression of Bcl-2 allows the development and maintenance of mature Baff-r–/– IgMlowIgDhigh B2 cells. We cannot exclude a mild effect of heterozygous loss of BAFF-R on B cell development in Baff-r+/– mice (see Table I). However, this effect is clearly much less significant than the reduction of B cell numbers by ~50% in offspring of A/WySnJ mice crossed to either A/J (28) or BALB/c mice (24). Therefore, it seems that in a heterozygous situation, the A/WySnJ BAFF-R can act as a dominant-negative molecule.

Our analysis of B cell development in Baff-r–/– mice revealed a developmental block at the transitional stages, most likely at the T1 to T2 transition. This corresponds well with the up-regulation of BAFF-R expression from the T1 to the T2 transitional stage (9, 46). It seems possible that BAFF-R engagement at the T1 transitional stage of B cell development promotes further differentiation to the T2 stage (10). Additionally, binding of BAFF to BAFF-R enhances survival of T2, T3, follicular, and MZ B cell subsets. We find <2 million mature B cells in the spleens of Baff-r–/– mice. These cells express reduced levels of CD21 and, to a lesser extent, CD23. Staining with Abs against CD1d and CD38 and immunohistochemistry revealed a near absence of MZ B cells, suggesting that the MZ B cell subset is exquisitely dependent on BAFF-R signals.

Monitoring B cell function in immune responses showed that Baff-r–/– B cells are able to produce class-switched Abs in response to TI-II and TD Ags. The reduction of Ab titers in immunized Baff-r–/– mice can be explained by the overall reduction of B cell numbers in the case of TD and the deficiency in MZ B cells in case of TI-II Ab responses.

The requirements for GC formation in mLNs and Peyer’s patches in response to microbial Ags differ from those for GC formation in the spleen upon antigenic stimulation (47). Therefore, we investigated the role of BAFF-R in this context and show that this receptor is dispensable for chronic GC responses triggered by Ags derived from the gut microflora. The fact that GALT GC reactions occur independently of BAFF-R and the intact B1 B cell population in Baff-r–/– mice most likely both contribute to the normal IgA serum levels observed in these mice.

Taken together, we show in this work that BAFF-R is essential for the survival of peripheral B2 cells from the T2 transitional stage on. In addition, BAFF-R seems to be indispensable for the development of MZ B cells and plays a role in the regulation of CD21 and, to a lesser extent, CD23 surface expression. Ablation of BAFF-R had no effect on the generation of B1 cells. These results suggest that the generation and maintenance of mature B2 and MZ B cells depend on the presence of at least two receptors, the BCR (48) and BAFF-R.

Previous analyses of the role of BAFF signaling in B cell physiology in Baff–/– and A/WySnJ mice expressing a mutant BAFF-R yielded some differences. However, due to the complex nature of the A/WySnJ mutation, it is impossible to distinguish whether these differences are due to BAFF-R-independent signals elicited by BAFF or residual signaling through the mutant receptor in A/WySnJ B cells. By generating BAFF-R-deficient mice, we attempted to clarify these isssues.

Recently, it was suggested that expression of CD21 and CD23 depends on BAFF (14). Residual B cells from A/WySnJ mice, in contrast, have normal surface levels of CD23 and seem to express only slightly decreased levels of CD21 (26). Our results indicate that BAFF regulates CD21 and CD23 expression through BAFF-R-dependent and -independent ways.

In both Baff–/– (14) and A/WySnJ (26) mice, normal proportions of cells with a MZ phenotype were observed among the residual splenic B cells. However, inhibition of BAFF function through transgenic expression of a TACI-Ig fusion protein prevented MZ B cell development altogether (49). In accordance with this finding, our results suggest a very strong reduction of MZ B cells in Baff-r–/– mice. It is therefore possible that the IgMhighIgDlow fraction found in Baff–/– mice (14) is composed entirely of T1 B cells. We propose that BAFF-R signaling is essential for MZ B cell development. A/WySnJ mice, in contrast, appear to contain normal proportions of CD21highCD23low MZ B cells. This suggests that the A/WySnJ mutation impairs BAFF-R-mediated survival signals, but does not completely interfere with MZ B cell differentiation.

MZ B cells are thought to play an important role in TI-II immune responses (50, 51, 52). The stronger reduction in MZ B cell numbers in Baff-r–/– compared with A/WySnJ mice could explain why the latter mice mount normal Ag-specific IgM TI-II responses upon immunizations with TI-II Ags (28), whereas Baff-r–/– mice produce lower levels of Ag-specific IgM than control mice. In response to a TD Ag, Baff-r–/– mice mount a robust, only slightly reduced Ag-specific IgM response, whereas the TD IgG1 primary and secondary immune responses are significantly reduced. Similar results were previously obtained in A/WySnJ mice and correlated to the general B cell deficiency (28). However, despite the prominent role of BAFF-R in B cell survival, BAFF-R could have additional functions in the control of GC responses (13, 15) and class-switch recombination (53) and could contribute in this way to the deficiencies of TD Ab responses in Baff-r–/– mice.

In contrast, Baff–/– mice, which have a similar defect in peripheral B cell numbers as Baff-r–/– and A/WySnJ mice, display a much more pronounced defect in humoral immunity (12). Because Taci–/– mice also show defects in TI-II responses, despite significantly elevated peripheral B cell numbers (20, 54), it seems plausible that BAFF promotes TI-II Ab responses also through TACI. It has been reported that BAFF has costimulatory activity for T cells (55, 56), which could account for a role of BAFF in TD immune responses independent of any of the described receptors. Although the exact mechanisms still need to be uncovered, we show in this study that in the control of humoral immune responses BAFF must operate at least partially independently of BAFF-R.


   Acknowledgments
 
We are grateful to S. Willms for Ab determinations, and to A. Egert, V. Dreier, D. Ghitza, and S. Linehan for help with ES cell injections and mouse work. We thank K. Otibopy for critical reading of the manuscript, and M. L. Scott, S. Shulga-Morskaya, and M. Dobles for sharing unpublished results with us.


   Footnotes
 
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.

1 This work was supported by the National Institutes of Health Grants AI057947 and 1R37AI054636 and the Uehara Memorial Foundation. Back

2 Address correspondence and reprint requests to Dr. Yoshiteru Sasaki or Dr. Marc Schmidt-Supprian, CBR Institute for Biomedical Research, 200 Longwood Avenue, Boston, MA 02115. E-mail address: sasaki{at}cbr.med.harvard.edu or supprian{at}cbr.med.harvard.edu Back

3 Abbreviations used in this paper: BAFF, TNF family member B cell-activating factor; BCMA, B cell maturation Ag; BM, bone marrow; CG, chicken {gamma}-globulin; ES, embryonic stem; GC, germinal center; HPRT, hypoxanthine phosphoribosyltransferase; LN, lymph node; mLN, mesenteric LN; MZ, marginal zone; NP, 4-hydroxy-3-nitrophenylacetyl; PNA, peanut agglutinin; T1/2/3, transitional type 1/2/3; TACI, transmembrane activator, calcium modulator, and cyclophilin ligand interactor; TD, T dependent; TI, T independent. Back

Received for publication March 24, 2004. Accepted for publication June 1, 2004.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Do, R. K., S. Chen-Kiang. 2002. Mechanism of BLyS action in B cell immunity. Cytokine Growth Factor Rev. 13:19.[Medline]
  2. Mackay, F., P. Schneider, P. Rennert, J. Browning. 2003. BAFF AND APRIL: a tutorial on B cell survival. Annu. Rev. Immunol. 21:231.[Medline]
  3. Melchers, F.. 2003. Actions of BAFF in B cell maturation and its effects on the development of autoimmune disease. Ann. Rheum. Dis. 62:(Suppl. 2):ii25.[Abstract/Free Full Text]
  4. Rolink, A. G., F. Melchers. 2002. BAFFled B cells survive and thrive: roles of BAFF in B-cell development. Curr. Opin. Immunol. 14:266.[Medline]
  5. Schneider, P., J. Tschopp. 2003. BAFF and the regulation of B cell survival. Immunol. Lett. 88:57.[Medline]
  6. Allman, D., B. Srivastava, R. C. Lindsley. 2004. Alternative routes to maturity: branch points and pathways for generating follicular and marginal zone B cells. Immunol. Rev. 197:147.[Medline]
  7. Cariappa, A., S. Pillai. 2002. Antigen-dependent B-cell development. Curr. Opin. Immunol. 14:241.[Medline]
  8. Batten, M., J. Groom, T. G. Cachero, F. Qian, P. Schneider, J. Tschopp, J. L. Browning, F. Mackay. 2000. BAFF mediates survival of peripheral immature B lymphocytes. J. Exp. Med. 192:1453.[Abstract/Free Full Text]
  9. Hsu, B. L., S. M. Harless, R. C. Lindsley, D. M. Hilbert, M. P. Cancro. 2002. Cutting edge: BLyS enables survival of transitional and mature B cells through distinct mediators. J. Immunol. 168:5993.[Abstract/Free Full Text]
  10. Rolink, A. G., J. Tschopp, P. Schneider, F. Melchers. 2002. BAFF is a survival and maturation factor for mouse B cells. Eur. J. Immunol. 32:2004.[Medline]
  11. Gross, J. A., S. R. Dillon, S. Mudri, J. Johnston, A. Littau, R. Roque, M. Rixon, O. Schou, K. P. Foley, H. Haugen, et al 2001. TACI-Ig neutralizes molecules critical for B cell development and autoimmune disease: impaired B cell maturation in mice lacking BLyS. Immunity 15:289.[Medline]
  12. Schiemann, B., J. L. Gommerman, K. Vora, T. G. Cachero, S. Shulga-Morskaya, M. Dobles, E. Frew, M. L. Scott. 2001. An essential role for BAFF in the normal development of B cells through a BCMA-independent pathway. Science 293:2111.[Abstract/Free Full Text]
  13. Rahman, Z. S., S. P. Rao, S. L. Kalled, T. Manser. 2003. Normal induction but attenuated progression of germinal center responses in BAFF and BAFF-R signaling-deficient mice. J. Exp. Med. 198:1157.[Abstract/Free Full Text]
  14. Gorelik, L., A. H. Cutler, G. Thill, S. D. Miklasz, D. E. Shea, C. Ambrose, S. A. Bixler, L. Su, M. L. Scott, S. L. Kalled. 2004. Cutting edge: BAFF regulates CD21/35 and CD23 expression independent of its B cell survival function. J. Immunol. 172:762.[Abstract/Free Full Text]
  15. Vora, K. A., L. C. Wang, S. P. Rao, Z. Y. Liu, G. R. Majeau, A. H. Cutler, P. S. Hochman, M. L. Scott, S. L. Kalled. 2003. Cutting edge: germinal centers formed in the absence of B cell-activating factor belonging to the TNF family exhibit impaired maturation and function. J. Immunol. 171:547.[Abstract/Free Full Text]
  16. Castigli, E., S. Scott, F. Dedeoglu, P. Bryce, H. Jabara, A. K. Bhan, E. Mizoguchi, R. S. Geha. 2004. Impaired IgA class switching in APRIL-deficient mice. Proc. Natl. Acad. Sci. USA 101:3903.[Abstract/Free Full Text]
  17. Varfolomeev, E., F. Kischkel, F. Martin, D. Seshasayee, H. Wang, D. Lawrence, C. Olsson, L. Tom, S. Erickson, D. French, et al 2004. APRIL-deficient mice have normal immune system development. Mol. Cell. Biol. 24:997.[Abstract/Free Full Text]
  18. Von Bulow, G. U., J. M. van Deursen, R. J. Bram. 2001. Regulation of the T-independent humoral response by TACI. Immunity 14:573.[Medline]
  19. Xu, S., K. P. Lam. 2001. B-cell maturation protein, which binds the tumor necrosis factor family members BAFF and APRIL, is dispensable for humoral immune responses. Mol. Cell. Biol. 21:4067.[Abstract/Free Full Text]
  20. Yan, M., H. Wang, B. Chan, M. Roose-Girma, S. Erickson, T. Baker, D. Tumas, I. S. Grewal, V. M. Dixit. 2001. Activation and accumulation of B cells in TACI-deficient mice. Nat. Immunol. 2:638.[Medline]
  21. Lentz, V. M., M. P. Cancro, F. E. Nashold, C. E. Hayes. 1996. Bcmd governs recruitment of new B cells into the stable peripheral B cell pool in the A/WySnJ mouse. J. Immunol. 157:598.[Abstract]
  22. Lentz, V. M., C. E. Hayes, M. P. Cancro. 1998. Bcmd decreases the life span of B-2 but not B-1 cells in A/WySnJ mice. J. Immunol. 160:3743.[Abstract/Free Full Text]
  23. Miller, D. J., C. E. Hayes. 1991. Phenotypic and genetic characterization of a unique B lymphocyte deficiency in strain A/WySnJ mice. Eur. J. Immunol. 21:1123.[Medline]
  24. Harless, S. M., V. M. Lentz, A. P. Sah, B. L. Hsu, K. Clise-Dwyer, D. M. Hilbert, C. E. Hayes, M. P. Cancro. 2001. Competition for BLyS-mediated signaling through Bcmd/BR3 regulates peripheral B lymphocyte numbers. Curr. Biol. 11:1986.[Medline]
  25. Yan, M., J. R. Brady, B. Chan, W. P. Lee, B. Hsu, S. Harless, M. Cancro, I. S. Grewal, V. M. Dixit. 2001. Identification of a novel receptor for B lymphocyte stimulator that is mutated in a mouse strain with severe B cell deficiency. Curr. Biol. 11:1547.[Medline]
  26. Amanna, I. J., J. P. Dingwall, C. E. Hayes. 2003. Enforced Bcl-xL gene expression restored splenic B lymphocyte development in BAFF-R mutant mice. J. Immunol. 170:4593.[Abstract/Free Full Text]
  27. Thompson, J. S., S. A. Bixler, F. Qian, K. Vora, M. L. Scott, T. G. Cachero, C. Hession, P. Schneider, I. D. Sizing, C. Mullen, et al 2001. BAFF-R, a newly identified TNF receptor that specifically interacts with BAFF. Science 293:2108.[Abstract/Free Full Text]
  28. Miller, D. J., K. D. Hanson, J. A. Carman, C. E. Hayes. 1992. A single autosomal gene defect severely limits IgG but not IgM responses in B lymphocyte-deficient A/WySnJ mice. Eur. J. Immunol. 22:373.[Medline]
  29. Bunting, M., K. E. Bernstein, J. M. Greer, M. R. Capecchi, K. R. Thomas. 1999. Targeting genes for self-excision in the germ line. Genes Dev. 13:1524.[Abstract/Free Full Text]
  30. Kontgen, F., G. Suss, C. Stewart, M. Steinmetz, H. Bluethmann. 1993. Targeted disruption of the MHC class II Aa gene in C57BL/6 mice. Int. Immunol. 5:957.[Abstract/Free Full Text]
  31. Schmidt-Supprian, M., W. Bloch, G. Courtois, K. Addicks, A. Israel, K. Rajewsky, M. Pasparakis. 2000. NEMO/IKK {gamma}-deficient mice model incontinentia pigmenti. Mol. Cell 5:981.[Medline]
  32. Strasser, A., A. W. Harris, S. Cory. 1991. bcl-2 transgene inhibits T cell death and perturbs thymic self-censorship. Cell 67:889.[Medline]
  33. Roes, J., K. Rajewsky. 1993. Immunoglobulin D (IgD)-deficient mice reveal an auxiliary receptor function for IgD in antigen-mediated recruitment of B cells. J. Exp. Med. 177:45.[Abstract/Free Full Text]
  34. Rodriguez, C. I., F. Buchholz, J. Galloway, R. Sequerra, J. Kasper, R. Ayala, A. F. Stewart, S. M. Dymecki. 2000. High-efficiency deleter mice show that FLPe is an alternative to Cre-loxP. Nat. Genet. 25:139.[Medline]
  35. Schwenk, F., U. Baron, K. Rajewsky. 1995. A cre-transgenic mouse strain for the ubiquitous deletion of loxP-flanked gene segments including deletion in germ cells. Nucleic Acids Res. 23:5080.[Free Full Text]
  36. Allman, D., R. C. Lindsley, W. DeMuth, K. Rudd, S. A. Shinton, R. R. Hardy. 2001. Resolution of three nonproliferative immature splenic B cell subsets reveals multiple selection points during peripheral B cell maturation. J. Immunol. 167:6834.[Abstract/Free Full Text]
  37. Martin, F., J. F. Kearney. 2002. Marginal-zone B cells. Nat. Rev. Immunol. 2:323.[Medline]
  38. Oliver, A. M., F. Martin, G. L. Gartland, R. H. Carter, J. F. Kearney. 1997. Marginal zone B cells exhibit unique activation, proliferative and immunoglobulin secretory responses. Eur. J. Immunol. 27:2366.[Medline]
  39. Berland, R., H. H. Wortis. 2002. Origins and functions of B-1 cells with notes on the role of CD5. Annu. Rev. Immunol. 20:253.[Medline]
  40. Cebra, J. J., A. George, C. E. Schrader. 1991. A microculture containing TH2 and dendritic cells supports the production of IgA by clones from both primary and IgA memory B cells and by single germinal center B cells from Peyer’s patches. Immunol. Res. 10:389.[Medline]
  41. Koni, P. A., R. A. Flavell. 1999. Lymph node germinal centers form in the absence of follicular dendritic cell networks. J. Exp. Med. 189:855.[Abstract/Free Full Text]
  42. Claudio, E., K. Brown, S. Park, H. Wang, U. Siebenlist. 2002. BAFF-induced NEMO-independent processing of NF-{kappa}B2 in maturing B cells. Nat. Immunol. 3:958.[Medline]
  43. Do, R. K., E. Hatada, H. Lee, M. R. Tourigny, D. Hilbert, S. Chen-Kiang. 2000. Attenuation of apoptosis underlies B lymphocyte stimulator enhancement of humoral immune response. J. Exp. Med. 192:953.[Abstract/Free Full Text]
  44. Hatada, E. N., R. K. Do, A. Orlofsky, H. C. Liou, M. Prystowsky, I. C. MacLennan, J. Caamano, S. Chen-Kiang. 2003. NF-{kappa}B1 p50 is required for BLyS attenuation of apoptosis but dispensable for processing of NF-{kappa}B2 p100 to p52 in quiescent mature B cells. J. Immunol. 171:761.[Abstract/Free Full Text]
  45. He, B., A. Chadburn, E. Jou, E. J. Schattner, D. M. Knowles, A. Cerutti. 2004. Lymphoma B cells evade apoptosis through the TNF family members BAFF/BLyS and APRIL. J. Immunol. 172:3268.[Abstract/Free Full Text]
  46. Gorelik, L., K. Gilbride, M. Dobles, S. L. Kalled, D. Zandman, M. L. Scott. 2003. Normal B cell homeostasis requires B cell activation factor production by radiation-resistant cells. J. Exp. Med. 198:937.[Abstract/Free Full Text]
  47. Casola, S., K. L. Otipoby, M. Alimzhanov, S. Humme, N. Uyttersprot, J. L. Kutok, M. C. Carroll, K. Rajewsky. 2004. B cell receptor signal strength determines B cell fate. Nat. Immunol. 5:317.[Medline]
  48. Lam, K. P., R. Kuhn, K. Rajewsky. 1997. In vivo ablation of surface immunoglobulin on mature B cells by inducible gene targeting results in rapid cell death. Cell 90:1073.[Medline]
  49. Tardivel, A., A. Tinel, S. Lens, Q. G. Steiner, E. Sauberli, A. Wilson, F. Mackay, A. G. Rolink, F. Beermann, J. Tschopp, P. Schneider. 2004. The anti-apoptotic factor Bcl-2 can functionally substitute for the B cell survival but not for the marginal zone B cell differentiation activity of BAFF. Eur. J. Immunol. 34:509.[Medline]
  50. Balazs, M., F. Martin, T. Zhou, J. Kearney. 2002. Blood dendritic cells interact with splenic marginal zone B cells to initiate T-independent immune responses. Immunity 17:341.[Medline]
  51. Guinamard, R., M. Okigaki, J. Schlessinger, J. V. Ravetch. 2000. Absence of marginal zone B cells in Pyk-2-deficient mice defines their role in the humoral response. Nat. Immunol. 1:31.[Medline]
  52. Martin, F., A. M. Oliver, J. F. Kearney. 2001. Marginal zone and B1 B cells unite in the early response against T-independent blood-borne particulate antigens. Immunity 14:617.[Medline]
  53. Litinskiy, M. B., B. Nardelli, D. M. Hilbert, B. He, A. Schaffer, P. Casali, A. Cerutti. 2002. DCs induce CD40-independent immunoglobulin class switching through BLyS and APRIL. Nat. Immunol. 3:822.[Medline]
  54. Seshasayee, D., P. Valdez, M. Yan, V. M. Dixit, D. Tumas, I. S. Grewal. 2003. Loss of TACI causes fatal lymphoproliferation and autoimmunity, establishing TACI as an inhibitory BLyS receptor. Immunity 18:279.[Medline]
  55. Huard, B., L. Arlettaz, C. Ambrose, V. Kindler, D. Mauri, E. Roosnek, J. Tschopp, P. Schneider, L. E. French. 2004. BAFF production by antigen-presenting cells provides T cell co-stimulation. Int. Immunol. 16:467.[Abstract/Free Full Text]
  56. Huard, B., P. Schneider, D. Mauri, J. Tschopp, L. E. French. 2001. T cell costimulation by the TNF ligand BAFF. J. Immunol. 167:6225.[Abstract/Free Full Text]

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