Human CD57+ germinal center-T cells are the major helpers for GC-B cells and induce class switch recombination
© Kim et al; licensee BioMed Central Ltd. 2005
Received: 15 August 2004
Accepted: 04 February 2005
Published: 04 February 2005
The function of CD57+ CD4+ T cells, constituting a major subset of germinal center T (GC-Th) cells in human lymphoid tissues, has been unclear. There have been contradictory reports regarding the B cell helping function of CD57+ GC-Th cells in production of immunoglobulin (Ig). Furthermore, the cytokine and co-stimulation requirement for their helper activity remains largely unknown. To clarify and gain more insight into their function in helping B cells, we systematically investigated the capacity of human tonsil CD57+ GC-Th cells in inducing B cell Ig synthesis.
We demonstrated that CD57+ GC-Th cells are highly efficient in helping B cell production of all four subsets of Ig (IgM, IgG, IgA and IgE) compared to other T-helper cells located in germinal centers or interfollicular areas. CD57+ GC-Th cells were particularly more efficient than other T cells in helping GC-B cells but not naïve B cells. CD57+ GC-Th cells induced the expression of activation-induced cytosine deaminase (AID) and class switch recombination in developing B cells. IgG1-3 and IgA1 were the major Ig isotypes induced by CD57+ GC-Th cells. CD40L, but not IL-4, IL-10 and IFN-γ, was critical in CD57+ GC-Th cell-driven B cell production of Ig. However, IL-10, when added exogenously, significantly enhanced the helper activity of CD57+ GC-Th cells, while TGF-β1 completely and IFN-γ partially suppressed the CD57+ GC-Th cell-driven Ig production.
CD57+CD4+ T cells in the germinal centers of human lymphoid tissues are the major T helper cell subset for GC-B cells in Ig synthesis. Their helper activity is consistent with their capacity to induce AID and class switch recombination, and can be regulated by CD40L, IL-4, IL-10 and TGF-β.
In germinal centers (GC), B cells undergo clonal expansion, somatic hyper-mutation in the variable region of antibody genes [1–3] and class switch recombination (CSR) from IgM to IgG, IgA, and IgE [4–8], processes that are dependent on helper T cells [9–11]. Antibodies to the CD57 epitope (HNK-1) have been used to identify a T cell type in germinal centers in human tonsils, spleen and lymph nodes. These cells are CD4+ T cells [12–14], exhibit a memory phenotype (CD45RO+CD45RA-)  and are not cytolytic . CD57+ GC-Th cells proliferate only when they are TCR-activated in the presence of IL-2 [17, 18]. CD57+ GC-Th cells express the B-cell zone homing chemokine receptor CXCR5 but not the T cell zone homing chemokine receptor CCR7, a pattern consistent with their specific localization in GC . Based upon their non-polarized cytokine profile, localization in GC and potential helper activity, it has been proposed that CD57+ GC-Th cells may constitute a novel effector T cell subset distinct from other well known effector T cell subsets such as Th1 and Th2 cells . Using a gene expression profiling study, we determined that CD57+ GC-Th cells are remotely related to other memory/effector T cells in global gene expression . The microarray study also revealed that CD57+ GC-Th cells have the unique capacity to produce CXCL13, a follicle chemokine implicated in recruitment of CXCR5+ cells [22, 23] and development of follicles/GCs . Because of their specific localization in germinal centers, the activities of CD57+ GC-Th cells on B cell proliferation and antibody production have been studied by several groups of scientists [19, 25–27]. The results of these previous studies reveled unique features of CD57+ GC-Th cells, but, when combined, they are inconclusive and widely vary from negative to neutral or positive in assessing the helper activities of CD57+ GC-Th cells.
To clarify and gain more insight into their function in helping B cells, we systematically investigated the capacity of human tonsil CD57+ GC-Th cells in inducing B cell Ig synthesis in naïve vs. germinal center B (GC-B) cells in comparison with other T cell subsets in human tonsils. We show that CD57+ GC-Th cells are more efficient than other germinal center or interfollicular T cells in supporting B cell production of Ig. CD57+ GC-Th cells, when compared to other T cells, have better helper activity for GC-B cells than for naïve B cells. CD57+ GC-Th cells induced the expression of activation-induced cytosine deaminase (AID) and CSR in developing B cells. CD40L, but not other major cytokines, is critical for the helper activity of CD57+ GC-Th cells. IL-10 positively and TGF-β1 negatively regulate the helper activity of CD57+ GC-Th cells.
Distribution and identification of T helper cell subsets in tonsils
CD57+ GC-Th cells are highly efficient in supporting Ig production by B cells
GC-B cells are the preferred target cells for the helper activity of CD57+ GC-Th cells
Because of their specific localization in germinal centers, the physiological target cells for CD57+ GC-Th cells would be GC-B cells rather than naïve B cells. We compared the helper activities of CD57+ GC-Th cells and CD57- CD69+/- CD4+ T cell subsets for B cells. In this study, we fractionated CD19+ B cells into two groups: IgD+CD38- naïve B and CD38+ IgD+/- GC B cells as shown in Figure 2B. CD57+ GC-Th cells, when co-cultured with GC-B cells, were significantly more efficient than CD57-CD69+ T cells in inducing the production of all four isotypes of Ig (Figure 3C). However, when co-cultured with naive B cells, CD57+ GC-Th cells were not significantly different from CD57-CD69+ T cells in their induction capacity of Ig (Figure 3B). Again, the helper activities of total CD57- T cells and CD57-CD69- T cells for naïve and GC-B cells were very low.
The relative composition of IgM, IgG, IgA and IgE produced in response to CD57+ GC-Th cells in the cultures with GC-B vs. naïve B cells was determined. CD57+ GC-Th cells drove the production of IgM, IgG, IgA and IgE in descending order (Figure 3D). Class-switched Ig isotypes such as IgG and IgA were more produced in GC-B cell cultures than in naïve B cell cultures. There was no statistically significant difference between the two T cell subsets (CD57+ GC-Th cells and CD4+CD57-CD69+ T cells) in the composition of Ig that they induced.
CD57+ GC-Th cells induce AID expression and class switch recombination in B cells
Ig class switch recombination between tandemly repeated S regions located 5' to each CH gene generates switch circles. We used a nested PCR technique designed to specifically detect switch circles but not genomic Ig sequences. Freshly isolated GC-B, but not naïve B cells, contained switch circles, which were detected as smeared multiple bands on agarose gels as expected. Naïve B cells cultured with CD57+ GC-Th cells generated detectable switch circles in a time-dependent manner (Figure 4D). We also used a DC-PCR technique  to detect γ3 and α1/2 switch circles (Figure 4E). Again, GC-Th cells induced switch circles in the naïve B cells cultured with GC-Th cells.
CD40L signal is necessary for, while cytokines modulate, the helper activity of CD57+ GC-Th cells
In the cultures with GC-B cells, blocking of CD40L again completely suppressed the B cell helping activity of CD57+ GC-Th cells (Figure 5B). However, IL-4 neutralization did not significantly affect the IgE production induced by CD57+ GC-Th cells, an activity different from that for naïve B cells. For GC-B cells, IFN-γ neutralization significantly increased the production of IgA as it did for naive B cells. The effects of IFN-γ neutralization on other Ig isotypes were smaller. While a slight decrease of IgE production in the cultures of GC-B cells and CD57+ GC-Th cells was observed, neutralization of endogenous IL-10 did not have any statistically significant effect on CD57+ GC-Th cell-driven Ig production in the cultures of either naïve or GC-B cells.
Exogenously-added IL-10 enhances while TGF-β1 completely suppresses the B cell helping activity of CD57+ GC-Th cells
To further examine the regulatory effect of cytokines, IL-4, IL-10, IFN-γ and TGF-β1 were exogenously added to the cultures of CD57+ GC-Th cells with B cells (Figure 5C and 5D). In cultures of CD57+ GC-Th cells with naïve B cells, exogenously added IL-4 enhanced the production of some subsets of Ig, but this effect was small and not statistically significant (Figure 5C). However exogenously added IFN-γ significantly suppressed the production of IgG, IgA and IgE. IL-10, when added exogenously, was highly efficient in enhancing the production of the four subsets of Ig. TGF-β1 completely suppressed the B cell-helping capacity of CD57+ GC-Th cells for naive B cells.
In cultures of CD57+ GC-Th cells with GC-B cells, IL-10 was again highly effective in enhancing the helper activity of CD57+ GC-Th cells, while TGF-β1 completely suppressed it (Figure 5D). IFN-γ partially but significantly suppressed the production of IgM, IgG, IgA and IgE. Exogenous IL-4 added to the cultures had no effect on the CD57+ GC-Th cell-driven Ig production in this condition (Figure 5D), which is in line with the negligible effect of anti-IL-4 on GC-B cells in Figure 5B.
CD57+ GC-Th cells are unique CD4+ T cells. They express the follicle homing receptor CXCR5 but lack the T cell area localization receptor CCR7 , and reside specifically in germinal centers [12–14]. CD57+ GC-Th cells proliferate only when appropriate signals such as TCR, CD28 and IL-2 are provided [17, 18]. GC-Th cells are widely disseminated and diverse in their TCR sequence . CD57+ GC-Th cells can express CD40L, ICOS and CXCL13 but are non-polarized T cells in their cytokine profile . It has been controversial and unclear whether CD57+ GC-Th cells are intrinsically more efficient in helping B cells than other T cells or they are simply localized in germinal centers without any significant differences from other T cells in their capacity as helpers. In this report, we systematically investigated the effector function of CD57+ GC-Th cells in regulation of B cell immunoglobulin production and its regulation.
When compared for their helper activities in inducing Ig synthesis by total B cells, CD57+ GC-Th cells were most efficient among the T cell subsets in tonsils. CD57+ GC-Th cells were particularly more efficient in their helper activity for GC-B cells vs. naïve B cells. CD57-CD69+ T cells were equally efficient to CD57+ GC-Th cells in inducing naïve B cell differentiation for Ig production, while they were less effective than CD57+ GC-Th cells in helping GC-B cells. This preference of CD57+ GC-Th cells for GC-B cells is physiologically relevant, since both the helper T cell subset and target B cells are specifically present in germinal centers. Therefore, CD57+ GC-Th cells would constitute an ideal T helper subset that can drive GC-B cell differentiation in germinal centers.
The effects of cytokines such as IL-4, IL-10, IFN-γ and CD40L on B cells in humans and mice have been well documented. It is considered that CD40L is a critical factor [4, 11, 32–37], and IL-4 and IL-10 are positive factors in regulation of B cell Ig production [38–44]. IFN-γ induces class switch to certain isotypes while it inhibits to others [45, 46]. In this study of the helper activity of CD57+ GC-Th cells, the positive role of IL-4 in promoting Ig production was valid only for IgE, but not IgG and IgA in the cultures of naïve B cells with CD57+ GC-Th cells (Figure 5). GC-B cells were even more resistant to the neutralization of IL-4 than naïve B cells in CD57+ GC-Th-cell driven Ig production. This smaller than expected effect of IL-4 may be due to the fact that there is not much IL-4 to neutralize in the cultures of GC-Th cells. This also suggests that GC-Th cells may provide helper signals to GC-B cells that are not significantly affected by IL-4.
AID  is a molecule essential for somatic hypermutation, CSR and Ig gene conversion [48–54]. We showed in this study that CD57+ GC-Th cells can induce AID expression (Figure 4A). This capacity is consistent with their ability to induce class switch recombination, which can be detected within a few days in the cultures of naïve B cells with CD57+ GC-Th cells. CD57+ GC-Th cells can induce the expression of productive IgG1-3 and IgA1 transcripts. However, CD57+ GC-Th cells were inefficient in induction of IgE (Figure 3, 4 and 5), which is consistent with their poor production capacity of IL-4 .
CD40L appears to be essential for the helper activity of CD57+ GC-Th cells. CD40L was required for the synthesis of all Ig isotypes in all the conditions tested regardless of whether the target B cells for CD57+ GC-Th cells were naïve or GC-B cells. While neutralization of IL-10 did not have any significant effect on the CD57+ GC-Th cell-driven Ig synthesis, exogenous IL-10 was highly effective in enhancing the Ig synthesis in our study. This could be due to insufficient neutralization of the IL-10 produced by CD57+ GC-Th cells, which are known to produce IL-10 upon TCR activation . Another possibility is that higher concentration of IL-10 than the level produced by CD57+ GC-Th cells may be necessary to significantly enhance the Ig response. Exogenous IFN-γ negatively regulates the CD57+ GC-Th cell-driven Ig synthesis, suggesting the potential roles of Th1 cells or other IFN-γ producing cells in regulation of the CD57+ GC-Th cells' helper activity. TGF-β1 plays dual roles: it is a switch factor for IgA and a potent immunosuppressive cytokine that inhibits Ig synthesis . We did not detect any switching effect but were able to detect its suppressive activity for the CD57+ GC-Th cell response. This could be due to the fact that the culture conditions (e.g. the saturating concentration of TGF-β) employed in our study appear to favor the detection of the suppressive function of TGF-β. Taken together, these results imply that Th1, Th2 and regulatory T cells, if present in germinal centers, could positively or negatively control the function of CD57+ GC-Th cells in regulation of humoral immune responses. Indeed, there are regulatory T cells in GCs that express surface TGF-β and can effectively suppress the function of CD57+ GC-Th cells .
Our results demonstrated the capacity of CD57+ GC-Th cells in supporting CSR and Ig synthesis in B cells, and revealed the factors that regulate their activity, thereby substantiating the so-far inconclusive function of CD57+ GC-Th cells. The fact that these T cells have preferential and efficient helper activity for GC-B cells and are specifically localized in GCs in large numbers suggests that CD57+ GC-Th cells are probably the major T helper subset responsible for supporting B cell differentiation for Ig production in germinal centers.
Mononuclear cells were prepared by density gradient centrifuge on histopaque 1077 (Sigma-Aldrich, St. Louis) from human tonsil pathological specimens obtained from young patients (3–10 yr) undergoing tonsillectomy to relieve obstruction of respiratory passages and improve drainage of the middle ear at Sagamore Surgical Center (Lafayette, IN). The use of human pathological specimens in this study was approved by the institutional review board at Purdue University. CD4+ T cells (purity >97%) were isolated by depleting non-CD4+ T cells using a magnetic bead depletion method (Miltenyi Biotec, Auburn, CA). After staining of the isolated CD4+ T cells with appropriate antibodies, CD57+ GC-Th cells (purity >95%) were isolated by a positive magnetic selection method (Miltenyi Biotec). CD4+CD57-CD69+ and CD4+CD57-CD69- T cell subsets (purity >95%) were further isolated from the CD57- T cell fraction by magnetically selecting CD69+ T cells (Miltenyi Biotec). Total B cells were isolated by rosetting with 2-amino-ethylisothiouronium bromide (AET)-treated sheep red blood cells followed by CD4+ T cell depletion (CD19+ cells > 99.5%). Naïve B cells (CD19+IgD+ cells >99%) were isolated from the total B cell fraction by depleting CD38+ T cells followed by positive magnetic selection of IgD+ B cells. CD19+CD38+IgD+/- GC-B cells (purity >95%) were isolated from the tonsil CD19+ B cells as described before  using anti-CD44, anti-IgD antibodies and pan-mouse IgG beads (Dynal, Brown Deer, WI).
All cell cultures were performed in RPMI1640 medium supplemented with 10% FBS, gentamycin, streptomycin, and penicillin. To cross-link the B cell receptors, isolated B cells were incubated for 2 h at 4°C with Sepharose-conjugated rabbit Ab to human Ig μ chain and human Ig (H + L) chain (Irvine Scientific, Santa Ana, CA; mixed 1:1 at 2 μg/ml), and then washed with cold PBS. 105 T and 105 B cells were co-cultured, unless indicated otherwise, in each well of 48-well plates in the presence of Staphylococcal enterotoxin B (SEB; 1 μg/ml, Sigma-Aldrich, St. Louis, MO). Cells were incubated in 5% CO2 incubators at 37°C for 3–8 days. Recombinant IL-4, IL-10, and TGF-β1 were purchased from R&D systems (Minneapolis, MN). Recombinant IFN-γ was obtained from BD Pharmingen (San Diego, CA). Purified CD154-blocking antibody (24–31) was obtained from Ancell Corporation (Bayport, MN). IL-4-blocking antibody (MP4-25D2) was purchased from BD Pharmingen. Blocking antibodies for IFN-γ (25718.111) and IL-10 (23738.111), and IgG1 isotype control antibody (11711.11) were purchased from R&D systems. All antibodies and reagents added to culture were azide-free. Cytokines were added at saturating concentrations: IL-4 (40 ng/ml), IL-10 (40 ng/ml), IFN-γ (200 ng/ml) and TGF-β1 (10 ng/ml). Neutralizing antibodies were added at following concentrations: anti-CD40L (20 μg/ml), anti-IL-4 (5 μg/ml), anti-IL-10 (5 μg/ml), anti-IFN-γ (2.5 μg/ml) and isotype antibody (5 μg/ml).
Flow cytometry analysis
T cells were stained with anti-human CD57 (NK-1; FITC, BD Pharmingen), anti-human CD69 (FN-50; FITC, BD Pharmingen), anti-human CD4 (S3.5; R-PE, Caltag Laboratories, Burlingame, CA), and anti-human CD3 (UCHT1; APC, BioLegend, San Diego, CA). B cells were stained with anti-CD19 (4G7; PerCP, BD Pharmingen), anti-human IgD (IAb-2, FITC, BD Pharmingen), anti-human CD38 (HTT2; R-PE, BD Pharmingen), and anti-human CD3 (UCHT1; APC, BioLegend). Stained cells were analyzed using a 4-color FACSCalibur™ (BD Biosciences).
In situ fluorescent immunohistochemistry
Frozen sections of tonsils were acetone-fixed and stained using antibodies to CD57 (BD Biosciences – Pharmingen; clone NK-1, labeled with FITC), CD69 (BD Biosciences – Pharmingen; clone FN50, labeled with FITC), IgD (BD Biosciences – Pharmingen; clone IA6-2, labeled with PE) and/or CD4 (Caltag Laboratories; clone S3.5, labeled with APC). Stained sections were analyzed using a confocal microscopy system (Bio-Rad MRC 1024UV and Nikon Diaphot 300 microscope) at Purdue Cytometry Lab.
Culture supernatants were assayed by ELISA as previously described . The sensitivity of this ELISA system is greater than 5 ng/ml, 300 pg/ml, 30 pg/ml, 600 pg/ml, and 15 pg/ml for IgM, IgG, IgG1, IgA and IgE, respectively.
Detection of productive VHDJH-CH Ig transcripts and reciprocal DNA recombination products
Total RNA was extracted from cultured cells with Trizol reagent (Invitrogen, Carlsbad, CA), and was reverse-transcribed into cDNAs with SuperScript™ First-Strand Synthesis System for RT-PCR (Invitrogen) according to the manufacturer's protocol. The primer pairs used in this study were designed by Cerutti et al. : IgM, FR3 forward (5'-GAC ACG GCT GTG TAT TAC TGT GCG-3') and Cμ reverse (5'-CCG AAT TCA GAC GAG GGG GAA AAG GGT T-3'); IgG1, FR3 forward and Cγ1 reverse (5'-GTT TTG TCA CAA GAT TTG GGC TC-3'); IgG2, FR3 forward and Cγ2 reverse (5'-GTG GGC ACT CGA CAC AAC ATT TGC G-3'); IgG3, FR3 forward and Cγ3 reverse (5'-TTG TGT CAC CAA GTG GGG TTT TGA GC-3'); IgG4, FR3 forward and Cγ4 reverse (5'-ATG GGC ATG GGG GAC CAT TTG GA-3'); IgA1, FR3 forward and Cα1 reverse (5'-GGG TGG CGG TTA GCG GGG TCT TGG-3'); IgA2, FR3 forward and Cα2 reverse (5'-TGT TGG CGG TTA GTG GGG TCT TGC A-3'); IgE, FR3 forward and Cε reverse (5'-CGG AGG TGG CAT TGG AGG-3'); human β-actin, actin forward (5'-ATG TTT GAG ACC TTC AAC AC-3') and actin reverse (5'-CAC GTC ACA CTT CAT GAT GG-3'). PCR reactions were performed on serially diluted cDNA samples using an Eppendorf master cycler (denaturation at 95°C for 15 s, annealing at 55°C for 45 s and extension at 72°C for 30°C; 30–35 cycles). Extrachromosomal switch circles were detected by a nested PCR strategy as previously described by others . Briefly, genomic/extrachromosomal DNA was isolated from fresh or cultured B cells using a QIAamp DNA Mini Kit (Qiagen, Valencia, CA) and was used as templates for amplification of Sγ1-Sμ, Sγ2-Sμ, Sγ3-Sμ, Sγ4-Sμ and Sα-Sγ. The PCR products were subject to second PCR using internal forward 5' Sγ or 5'Iα1/2i and reverse 3'Sμi or 3'γi primer pairs. This method has been verified for specificity using positive controls . Additionally, we amplified genomic β-actin gene as a control using 5'-GTA CCA CTG GCA TCG TGA TGG ACT-3' (G-actin-forward-1 primer) and 5'-ATC CAC ACG GAG TAC TTG CGC TCA-3' (G-actin-reverse-1) for the first PCR; and 5'-AGA AGA GCT ACG AGC TGC CTG AC-3' (G-actin-forward-2) and 5'-TGA GGA CCC TGG ATG TGA CAG CT-3' (G-actin-reverse-2) for the second PCR. Additionally, we used a DC-PCR technique [30, 58] to demonstrate the presence of switch circles (γ3 and α1/2) in human B cells. Please see the reference  for primer sequences.
RT-PCR analysis for AID expression
Total RNA was extracted from freshly isolated or cultured cells using Trizol reagent (Invitrogen, Carlsbad, CA), and was reverse-transcribed into cDNAs with SuperScript™ II Reverse Transcriptase. RT-PCR amplification of AID was performed using the two primers: AID-forward (5'-GAT GAA CCG GAG GAA GTT TC-3') and AID-reverse (5'-TCA GCC TTG CGG TCC TCA CAG-3'), which generated a specific 351 bp PCR product after 30 cycles of PCR reaction (30 s at 94°C, 30 s at 60°C, and 60 s at 72°C). β-actin was also amplified as a control.
Student's paired t-test was used. P values smaller than 0.05 were considered significant.
List of abbreviations used
- GC-Th cells:
germinal center T helper cells
- GC-B cells:
germinal center B cells
activation-induced cytosine deaminase
class switch recombination
staphylococcal enterotoxin B.
We thank Dr. Meenakshi Roy (UCLA) and Dr. Harm HogenEsch (Purdue University) for their help/advice, and thank Nancy Petretic for her excellent assistance in flow analysis. This study has been supported from grants from the Leukemia and Lymphoma Society, the Leukemia Research Foundation, and the American Cancer Society (#IRG-58-006-44) to CHK.
- Liu YJ, de Bouteiller O, Fugier-Vivier I: Mechanisms of selection and differentiation in germinal centers. Curr Opin Immunol. 1997, 9: 256-262. 10.1016/S0952-7915(97)80145-8.View ArticlePubMedGoogle Scholar
- Clark EA, Ledbetter JA: How B and T cells talk to each other. Nature. 1994, 367: 425-428. 10.1038/367425a0.View ArticlePubMedGoogle Scholar
- Ziegner M, Steinhauser G, Berek C: Development of antibody diversity in single germinal centers: selective expansion of high-affinity variants. Eur J Immunol. 1994, 24: 2393-2400.View ArticlePubMedGoogle Scholar
- Aruffo A, Farrington M, Hollenbaugh D, Li X, Milatovich A, Nonoyama S, Bajorath J, Grosmaire LS, Stenkamp R, Neubauer M, et al.: The CD40 ligand, gp39, is defective in activated T cells from patients with X-linked hyper-IgM syndrome. Cell. 1993, 72: 291-300. 10.1016/0092-8674(93)90668-G.View ArticlePubMedGoogle Scholar
- Jumper MD, Splawski JB, Lipsky PE, Meek K: Ligation of CD40 induces sterile transcripts of multiple Ig H chain isotypes in human B cells. J Immunol. 1994, 152: 438-445.PubMedGoogle Scholar
- Snapper CM, Paul WE: Interferon-gamma and B cell stimulatory factor-1 reciprocally regulate Ig isotype production. Science. 1987, 236: 944-947.View ArticlePubMedGoogle Scholar
- Stavnezer J: Immunoglobulin class switching. Curr Opin Immunol. 1996, 8: 199-205. 10.1016/S0952-7915(96)80058-6.View ArticlePubMedGoogle Scholar
- Liu YJ, Malisan F, de Bouteiller O, Guret C, Lebecque S, Banchereau J, Mills FC, Max EE, Martinez-Valdez H: Within germinal centers, isotype switching of immunoglobulin genes occurs after the onset of somatic mutation. Immunity. 1996, 4: 241-250. 10.1016/S1074-7613(00)80432-X.View ArticlePubMedGoogle Scholar
- Croft M, Swain SL: B cell response to fresh and effector T helper cells. Role of cognate T- B interaction and the cytokines IL-2, IL-4, and IL-6. J Immunol. 1991, 146: 4055-4064.PubMedGoogle Scholar
- Lane P, Traunecker A, Hubele S, Inui S, Lanzavecchia A, Gray D: Activated human T cells express a ligand for the human B cell- associated antigen CD40 which participates in T cell-dependent activation of B lymphocytes. Eur J Immunol. 1992, 22: 2573-2578.View ArticlePubMedGoogle Scholar
- Noelle RJ, Ledbetter JA, Aruffo A: CD40 and its ligand, an essential ligand-receptor pair for thymus-dependent B-cell activation. Immunol Today. 1992, 13: 431-433. 10.1016/0167-5699(92)90068-I.View ArticlePubMedGoogle Scholar
- Porwit-Ksiazek A, Ksiazek T, Biberfeld P: Leu 7+ (HNK-1+) cells. I. Selective compartmentalization of Leu 7+ cells with different immunophenotypes in lymphatic tissues and blood. Scand J Immunol. 1983, 18: 485-493.View ArticlePubMedGoogle Scholar
- Velardi A, Mingari MC, Moretta L, Grossi CE: Functional analysis of cloned germinal center CD4+ cells with natural killer cell-related features. Divergence from typical T helper cells. J Immunol. 1986, 137: 2808-2813.PubMedGoogle Scholar
- Hsu SM, Cossman J, Jaffe ES: Lymphocyte subsets in normal human lymphoid tissues. Am J Clin Pathol. 1983, 80: 21-30.PubMedGoogle Scholar
- Bowen MB, Butch AW, Parvin CA, Levine A, Nahm MH: Germinal center T cells are distinct helper-inducer T cells. Hum Immunol. 1991, 31: 67-75. 10.1016/0198-8859(91)90050-J.View ArticlePubMedGoogle Scholar
- Bouzahzah F, Bosseloir A, Heinen E, Simar LJ: Human germinal center CD4+CD57+ T cells act differently on B cells than do classical T-helper cells. Dev Immunol. 1995, 4: 189-197.PubMed CentralView ArticlePubMedGoogle Scholar
- Bouzahzah F, Bosseloir A, Heinen E, Simar LJ: Germinal center T cells: analysis of their proliferative capacity. Adv Exp Med Biol. 1995, 378: 305-307.View ArticlePubMedGoogle Scholar
- Johansson-Lindbom B, Ingvarsson S, Borrebaeck CA: Germinal centers regulate human Th2 development. J Immunol. 2003, 171: 1657-1666.View ArticlePubMedGoogle Scholar
- Kim CH, Rott LS, Clark-Lewis I, Campbell DJ, Wu L, Butcher EC: Subspecialization of CXCR5+ T cells: B helper activity is focused in a germinal center-localized subset of CXCR5+ T cells. J Exp Med. 2001, 193: 1373-1381. 10.1084/jem.193.12.1373.PubMed CentralView ArticlePubMedGoogle Scholar
- Kim CH, Campbell DJ, Butcher EC: Nonpolarized memory T cells. Trends in Immunology. 2001, 22: 527-530. 10.1016/S1471-4906(01)02029-4.View ArticlePubMedGoogle Scholar
- Kim CH, Lim HW, Kim JR, Rott L, Hillsamer P, Butcher EC: Unique gene expression program of human germinal center T helper cells. Blood. 2004, 104: 1952-1960. 10.1182/blood-2004-03-1206.View ArticlePubMedGoogle Scholar
- Gunn MD, Ngo VN, Ansel KM, Ekland EH, Cyster JG, Williams LT: A B-cell-homing chemokine made in lymphoid follicles activates Burkitt's lymphoma receptor-1. Nature. 1998, 391: 799-803. 10.1038/35876.View ArticlePubMedGoogle Scholar
- Legler DF, Loetscher M, Roos RS, Clark-Lewis I, Baggiolini M, Moser B: B cell-attracting chemokine 1, a human CXC chemokine expressed in lymphoid tissues, selectively attracts B lymphocytes via BLR1/CXCR5. J Exp Med. 1998, 187: 655-660. 10.1084/jem.187.4.655.PubMed CentralView ArticlePubMedGoogle Scholar
- Ansel KM, Ngo VN, Hyman PL, Luther SA, Forster R, Sedgwick JD, Browning JL, Lipp M, Cyster JG: A chemokine-driven positive feedback loop organizes lymphoid follicles. Nature. 2000, 406: 309-314. 10.1038/35018581.View ArticlePubMedGoogle Scholar
- Banerjee D, Baril J, Bell DA, McFarlane D, Karim R: Suppression of immunoglobulin production by germinal centre HNK-1+ CD3+ cells. Adv Exp Med Biol. 1988, 237: 421-425.View ArticlePubMedGoogle Scholar
- Velardi A, Tilden AB, Millo R, Grossi CE: Isolation and characterization of Leu 7+ germinal-center cells with the T helper-cell phenotype and granular lymphocyte morphology. J Clin Immunol. 1986, 6: 205-215. 10.1007/BF00918700.View ArticlePubMedGoogle Scholar
- Andersson E, Dahlenborg K, Ohlin M, Borrebaeck CA, Carlsson R: Immunoglobulin production induced by CD57+ GC-derived helper T cells in vitro requires addition of exogenous IL-2. Cell Immunol. 1996, 169: 166-173. 10.1006/cimm.1996.0107.View ArticlePubMedGoogle Scholar
- Mori S, Mohri N, Morita H, Yamaguchi K, Shimamine T: Germinal centers as the main sites of Leu 7 (HNK-1) lymphocytes in human lymph node and tonsil. Nippon Ketsueki Gakkai Zasshi. 1983, 46: 1016-1019.PubMedGoogle Scholar
- Ritchie AW, James K, Micklem HS: The distribution and possible significance of cells identified in human lymphoid tissue by the monoclonal antibody HNK-1. Clin Exp Immunol. 1983, 51: 439-447.PubMed CentralPubMedGoogle Scholar
- Weckert HA, Hughes JA, Benson EM, Dunn IS: Quantifiable analysis of human immunoglobulin heavy chain class-switch recombination to all isotypes. J Immunol Methods. 2000, 233: 141-158. 10.1016/S0022-1759(99)00132-5.View ArticlePubMedGoogle Scholar
- Golby SJ, Dunn-Walters DK, Spencer J: Human tonsillar germinal center T cells are a diverse and widely disseminated population. Eur J Immunol. 1999, 29: 3729-3736. 10.1002/(SICI)1521-4141(199911)29:11<3729::AID-IMMU3729>3.3.CO;2-9.View ArticlePubMedGoogle Scholar
- Durandy A, Schiff C, Bonnefoy JY, Forveille M, Rousset F, Mazzei G, Milili M, Fischer A: Induction by anti-CD40 antibody or soluble CD40 ligand and cytokines of IgG, IgA and IgE production by B cells from patients with X-linked hyper IgM syndrome. Eur J Immunol. 1993, 23: 2294-2299.View ArticlePubMedGoogle Scholar
- Nonoyama S, Hollenbaugh D, Aruffo A, Ledbetter JA, Ochs HD: B cell activation via CD40 is required for specific antibody production by antigen-stimulated human B cells. J Exp Med. 1993, 178: 1097-1102. 10.1084/jem.178.3.1097.View ArticlePubMedGoogle Scholar
- Allen RC, Armitage RJ, Conley ME, Rosenblatt H, Jenkins NA, Copeland NG, Bedell MA, Edelhoff S, Disteche CM, Simoneaux DK, et al.: CD40 ligand gene defects responsible for X-linked hyper-IgM syndrome. Science. 1993, 259: 990-993.View ArticlePubMedGoogle Scholar
- DiSanto JP, Bonnefoy JY, Gauchat JF, Fischer A, de Saint Basile G: CD40 ligand mutations in x-linked immunodeficiency with hyper-IgM. Nature. 1993, 361: 541-543. 10.1038/361541a0.View ArticlePubMedGoogle Scholar
- Xu J, Foy TM, Laman JD, Elliott EA, Dunn JJ, Waldschmidt TJ, Elsemore J, Noelle RJ, Flavell RA: Mice deficient for the CD40 ligand. Immunity. 1994, 1: 423-431. 10.1016/1074-7613(94)90073-6.View ArticlePubMedGoogle Scholar
- Cerutti A, Zan H, Schaffer A, Bergsagel L, Harindranath N, Max EE, Casali P: CD40 ligand and appropriate cytokines induce switching to IgG, IgA, and IgE and coordinated germinal center and plasmacytoid phenotypic differentiation in a human monoclonal IgM+IgD+ B cell line. J Immunol. 1998, 160: 2145-2157.PubMed CentralPubMedGoogle Scholar
- Lebman DA, Coffman RL: Interleukin 4 causes isotype switching to IgE in T cell-stimulated clonal B cell cultures. J Exp Med. 1988, 168: 853-862. 10.1084/jem.168.3.853.View ArticlePubMedGoogle Scholar
- Moon HB, Severinson E, Heusser C, Johansson SG, Moller G, Persson U: Regulation of IgG1 and IgE synthesis by interleukin 4 in mouse B cells. Scand J Immunol. 1989, 30: 355-361.View ArticlePubMedGoogle Scholar
- Spiegelberg HL, O'Connor RD, Falkoff RJ, Beck L: Interleukin-4 induced IgE and IgG4 secretion by B cells from atopic dermatitis patients. Int Arch Allergy Appl Immunol. 1991, 94: 181-183.View ArticlePubMedGoogle Scholar
- Gascan H, Gauchat JF, Roncarolo MG, Yssel H, Spits H, de Vries JE: Human B cell clones can be induced to proliferate and to switch to IgE and IgG4 synthesis by interleukin 4 and a signal provided by activated CD4+ T cell clones. J Exp Med. 1991, 173: 747-750. 10.1084/jem.173.3.747.View ArticlePubMedGoogle Scholar
- Punnonen J, Aversa G, Cocks BG, McKenzie AN, Menon S, Zurawski G, de Waal Malefyt R, de Vries JE: Interleukin 13 induces interleukin 4-independent IgG4 and IgE synthesis and CD23 expression by human B cells. Proc Natl Acad Sci U S A. 1993, 90: 3730-3734.PubMed CentralView ArticlePubMedGoogle Scholar
- Fujieda S, Zhang K, Saxon A: IL-4 plus CD40 monoclonal antibody induces human B cells gamma subclass-specific isotype switch: switching to gamma 1, gamma 3, and gamma 4, but not gamma 2. J Immunol. 1995, 155: 2318-2328.PubMedGoogle Scholar
- Briere F, Servet-Delprat C, Bridon JM, Saint-Remy JM, Banchereau J: Human interleukin 10 induces naive surface immunoglobulin D+ (sIgD+) B cells to secrete IgG1 and IgG3. J Exp Med. 1994, 179: 757-762. 10.1084/jem.179.2.757.View ArticlePubMedGoogle Scholar
- Bossie A, Vitetta ES: IFN-gamma enhances secretion of IgG2a from IgG2a-committed LPS-stimulated murine B cells: implications for the role of IFN-gamma in class switching. Cell Immunol. 1991, 135: 95-104. 10.1016/0008-8749(91)90257-C.View ArticlePubMedGoogle Scholar
- Xu L, Rothman P: IFN-gamma represses epsilon germline transcription and subsequently down-regulates switch recombination to epsilon. Int Immunol. 1994, 6: 515-521.View ArticlePubMedGoogle Scholar
- Muramatsu M, Sankaranand VS, Anant S, Sugai M, Kinoshita K, Davidson NO, Honjo T: Specific expression of activation-induced cytidine deaminase (AID), a novel member of the RNA-editing deaminase family in germinal center B cells. J Biol Chem. 1999, 274: 18470-18476. 10.1074/jbc.274.26.18470.View ArticlePubMedGoogle Scholar
- Martin A, Bardwell PD, Woo CJ, Fan M, Shulman MJ, Scharff MD: Activation-induced cytidine deaminase turns on somatic hypermutation in hybridomas. Nature. 2002, 415: 802-806.View ArticlePubMedGoogle Scholar
- Muramatsu M, Kinoshita K, Fagarasan S, Yamada S, Shinkai Y, Honjo T: Class switch recombination and hypermutation require activation-induced cytidine deaminase (AID), a potential RNA editing enzyme. Cell. 2000, 102: 553-563. 10.1016/S0092-8674(00)00078-7.View ArticlePubMedGoogle Scholar
- Revy P, Muto T, Levy Y, Geissmann F, Plebani A, Sanal O, Catalan N, Forveille M, Dufourcq-Labelouse R, Gennery A, Tezcan I, Ersoy F, Kayserili H, Ugazio AG, Brousse N, Muramatsu M, Notarangelo LD, Kinoshita K, Honjo T, Fischer A, Durandy A: Activation-induced cytidine deaminase (AID) deficiency causes the autosomal recessive form of the Hyper-IgM syndrome (HIGM2). Cell. 2000, 102: 565-575. 10.1016/S0092-8674(00)00079-9.View ArticlePubMedGoogle Scholar
- Minegishi Y, Lavoie A, Cunningham-Rundles C, Bedard PM, Hebert J, Cote L, Dan K, Sedlak D, Buckley RH, Fischer A, Durandy A, Conley ME: Mutations in activation-induced cytidine deaminase in patients with hyper IgM syndrome. Clin Immunol. 2000, 97: 203-210. 10.1006/clim.2000.4956.View ArticlePubMedGoogle Scholar
- Meffre E, Catalan N, Seltz F, Fischer A, Nussenzweig MC, Durandy A: Somatic hypermutation shapes the antibody repertoire of memory B cells in humans. J Exp Med. 2001, 194: 375-378. 10.1084/jem.194.3.375.PubMed CentralView ArticlePubMedGoogle Scholar
- Arakawa H, Hauschild J, Buerstedde JM: Requirement of the activation-induced deaminase (AID) gene for immunoglobulin gene conversion. Science. 2002, 295: 1301-1306. 10.1126/science.1067308.View ArticlePubMedGoogle Scholar
- Nagaoka H, Muramatsu M, Yamamura N, Kinoshita K, Honjo T: Activation-induced deaminase (AID)-directed hypermutation in the immunoglobulin Smu region: implication of AID involvement in a common step of class switch recombination and somatic hypermutation. J Exp Med. 2002, 195: 529-534. 10.1084/jem.20012144.PubMed CentralView ArticlePubMedGoogle Scholar
- van Vlasselaer P, Punnonen J, de Vries JE: Transforming growth factor-beta directs IgA switching in human B cells. J Immunol. 1992, 148: 2062-2067.PubMedGoogle Scholar
- Lim HW, Hillsamer P, Kim CH: Regulatory T cells can migrate to follicles upon T cell activation and suppress GC-Th cells and GC-Th cell-driven B cell responses. J Clin Invest. 2004, 114: 1640-1649. 10.1172/JCI200422325.PubMed CentralView ArticlePubMedGoogle Scholar
- Roy MP, Kim CH, Butcher EC: Cytokine control of memory B cell homing machinery. J Immunol. 2002, 169: 1676-1682.View ArticlePubMedGoogle Scholar
- Chu CC, Paul WE, Max EE: Quantitation of immunoglobulin mu-gamma 1 heavy chain switch region recombination by a digestion-circularization polymerase chain reaction method. Proc Natl Acad Sci U S A. 1992, 89: 6978-6982.PubMed CentralView ArticlePubMedGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.