InVivoMAb recombinant human IgG1 Fc

Catalog #BE0096
Product Citations:
11
Clone:
human Fc-G1

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Product Details

This recombinant human IgG1 Fc is the Fc fragment of human IgG1 only and does not contain the Fab fragments. The molecular mass of the recombinant human IgG1 Fc is approximately 34 kDa in SDS-PAGE under reducing conditions. This product is commonly used as an isotype control for human IgG1 antibodies as well as fusion proteins containing the human IgG Fc fragment.

Specifications

Recommended Dilution Buffer InVivoPure pH 7.0 Dilution Buffer
Formulation PBS, pH 7.0
Contains no stabilizers or preservatives
Endotoxin <2EU/mg (<0.002EU/Ī¼g)
Determined by LAL gel clotting assay
Purity >95%
Determined by SDS-PAGE
Sterility 0.2 Āµm filtration
Production Purified from cell culture supernatant in an animal-free facility
Purification Protein A
RRID AB_1107777
Storage The antibody solution should be stored at the stock concentration at 4Ā°C. Do not freeze.
Moon, S., et al. (2021). "Niche-specific MHC II and PD-L1 regulate CD4+CD8Ī±Ī±+ intraepithelial lymphocyte differentiation" J Exp Med 218(4). PubMed

Conventional CD4+ T cells are differentiated into CD4+CD8Ī±Ī±+ intraepithelial lymphocytes (IELs) in the intestine; however, the roles of intestinal epithelial cells (IECs) are poorly understood. Here, we showed that IECs expressed MHC class II (MHC II) and programmed death-ligand 1 (PD-L1) induced by the microbiota and IFN-Ī³ in the distal part of the small intestine, where CD4+ T cells were transformed into CD4+CD8Ī±Ī±+ IELs. Therefore, IEC-specific deletion of MHC II and PD-L1 hindered the development of CD4+CD8Ī±Ī±+ IELs. Intracellularly, PD-1 signals supported the acquisition of CD8Ī±Ī± by down-regulating the CD4-lineage transcription factor, T helper-inducing POZ/KrĆ¼ppel-like factor (ThPOK), via the Src homology 2 domain-containing tyrosine phosphatase (SHP) pathway. Our results demonstrate that noncanonical antigen presentation with cosignals from IECs constitutes niche adaptation signals to develop tissue-resident CD4+CD8Ī±Ī±+ IELs.

Christensen, A. D., et al. (2015). "Depletion of regulatory T cells in a hapten-induced inflammation model results in prolonged and increased inflammation driven by T cells" Clin Exp Immunol 179(3): 485-499. PubMed

Regulatory T cells (Tregs ) are known to play an immunosuppressive role in the response of contact hypersensitivity (CHS), but neither the dynamics of Tregs during the CHS response nor the exaggerated inflammatory response after depletion of Tregs has been characterized in detail. In this study we show that the number of Tregs in the challenged tissue peak at the same time as the ear-swelling reaches its maximum on day 1 after challenge, whereas the number of Tregs in the draining lymph nodes peaks at day 2. As expected, depletion of Tregs by injection of a monoclonal antibody to CD25 prior to sensitization led to a prolonged and sustained inflammatory response which was dependent upon CD8 T cells, and co-stimulatory blockade with cytotoxic T lymphocyte antigen-4-immunoglobulin (CTLA-4-Ig) suppressed the exaggerated inflammation. In contrast, blockade of the interleukin (IL)-10-receptor (IL-10R) did not further increase the exaggerated inflammatory response in the Treg -depleted mice. In the absence of Tregs , the response changed from a mainly acute reaction with heavy infiltration of neutrophils to a sustained response with more chronic characteristics (fewer neutrophils and dominated by macrophages). Furthermore, depletion of Tregs enhanced the release of cytokines and chemokines locally in the inflamed ear and augmented serum levels of the systemic inflammatory mediators serum amyloid (SAP) and haptoglobin early in the response.

Kim, Y. U., et al. (2015). "Regulation of autoimmune germinal center reactions in lupus-prone BXD2 mice by follicular helper T cells" PLoS One 10(3): e0120294. PubMed

BXD2 mice spontaneously develop autoantibodies and subsequent glomerulonephritis, offering a useful animal model to study autoimmune lupus. Although initial studies showed a critical contribution of IL-17 and Th17 cells in mediating autoimmune B cell responses in BXD2 mice, the role of follicular helper T (Tfh) cells remains incompletely understood. We found that both the frequency of Th17 cells and the levels of IL-17 in circulation in BXD2 mice were comparable to those of wild-type. By contrast, the frequency of PD-1+ CXCR5+ Tfh cells was significantly increased in BXD2 mice compared with wild-type mice, while the frequency of PD-1+ CXCR5+ Foxp3+ follicular regulatory T (Tfr) cells was reduced in the former group. The frequency of Tfh cells rather than that of Th17 cells was positively correlated with the frequency of germinal center B cells as well as the levels of autoantibodies to dsDNA. More importantly, CXCR5+ CD4+ T cells isolated from BXD2 mice induced the production of IgG from naive B cells in an IL-21-dependent manner, while CCR6+ CD4+ T cells failed to do so. These results together demonstrate that Tfh cells rather than Th17 cells contribute to the autoimmune germinal center reactions in BXD2 mice.

Lindebo Holm, T., et al. (2012). "Pharmacological Evaluation of the SCID T Cell Transfer Model of Colitis: As a Model of Crohn's Disease" Int J Inflam 2012: 412178. PubMed

Animal models are important tools in the development of new drug candidates against the inflammatory bowel diseases (IBDs) Crohnā€™s disease and ulcerative colitis. In order to increase the translational value of these models, it is important to increase knowledge relating to standard drugs. Using the SCID adoptive transfer colitis model, we have evaluated the effect of currently used IBD drugs and IBD drug candidates, that is, anti-TNF-alpha, TNFR-Fc, anti-IL-12p40, anti-IL-6, CTLA4-Ig, anti-alpha4beta7 integrin, enrofloxacin/metronidazole, and cyclosporine. We found that anti-TNF-alpha, antibiotics, anti-IL-12p40, anti-alpha4beta7 integrin, CTLA4-Ig, and anti-IL-6 effectively prevented onset of colitis, whereas TNFR-Fc and cyclosporine did not. In intervention studies, antibiotics, anti-IL-12p40, and CTLA4-Ig induced remission, whereas the other compounds did not. The data suggest that the adoptive transfer model and the inflammatory bowel diseases have some main inflammatory pathways in common. The finding that some well-established IBD therapeutics do not have any effect in the model highlights important differences between the experimental model and the human disease.

Coley, S. M., et al. (2009). "IFN-gamma dictates allograft fate via opposing effects on the graft and on recipient CD8 T cell responses" J Immunol 182(1): 225-233. PubMed

CD8 T cells are necessary for costimulation blockade-resistant rejection. However, the mechanism by which CD8 T cells mediate rejection in the absence of major costimulatory signals is poorly understood. IFN-gamma promotes CD8 T cell-mediated immune responses, but IFN-gamma-deficient mice show early graft loss despite costimulation blockade. In contrast, we found that IFN-gamma receptor knockout mice show dramatically prolonged graft survival under costimulation blockade. To investigate this paradox, we addressed the effects of IFN-gamma on T cell alloresponses in vivo independent of the effects of IFN-gamma on graft survival. We identified a donor-specific CD8 T cell breakthrough response temporally correlated with costimulation blockade-resistant rejection. Neither IFN-gamma receptor knockout recipients nor IFN-gamma-deficient recipients showed a CD8 breakthrough response. Graft death on IFN-gamma-deficient recipients despite costimulation blockade could be explained by the lack of IFN-gamma available to act on the graft. Indeed, the presence of IFN-gamma was necessary for graft survival on IFN-gamma receptor knockout recipients, as either IFN-gamma neutralization or the lack of the IFN-gamma receptor on the graft precipitated early graft loss. Thus, IFN-gamma is required both for the recipient to mount a donor-specific CD8 T cell response under costimulation blockade as well as for the graft to survive after allotransplantation.

    • Cancer Research
    • ,
    • Genetics
    • ,
    • Immunology and Microbiology
    Targeting IL-17A enhances imatinib efficacy in Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia.

    In Nature Communications on 3 January 2024 by Wang, F., Li, Y., et al.

    PubMed

    Dysregulated hematopoietic niches remodeled by leukemia cells lead to imbalances in immunological mediators that support leukemogenesis and drug resistance. Targeting immune niches may ameliorate disease progression and tyrosine kinase inhibitor (TKI) resistance in Philadelphia chromosome-positive B-ALL (Ph+ B-ALL). Here, we show that T helper type 17 (Th17) cells and IL-17A expression are distinctively elevated in Ph+ B-ALL patients. IL-17A promotes the progression of Ph+ B-ALL. Mechanistically, IL-17A activates BCR-ABL, IL6/JAK/STAT3, and NF-kB signalling pathways in Ph+ B-ALL cells, resulting in robust cell proliferation and survival. In addition, IL-17A-activated Ph+ B-ALL cells secrete the chemokine CXCL16, which in turn promotes Th17 differentiation, attracts Th17 cells and forms a positive feedback loop supporting leukemia progression. These data demonstrate an involvement of Th17 cells in Ph+ B-ALL progression and suggest potential therapeutic options for Ph+ B-ALL with Th17-enriched niches. Ā© 2024. The Author(s).

    • Pathology
    Defective LAT signalosome pathology in mice mimics human IgG4-related disease at single-cell level.

    In The Journal of Experimental Medicine on 6 November 2023 by Joachim, A., Aussel, R., et al.

    PubMed

    Mice with a loss-of-function mutation in the LAT adaptor (LatY136F) develop an autoimmune and type 2 inflammatory disorder called defective LAT signalosome pathology (DLSP). We analyzed via single-cell omics the trajectory leading to LatY136F DLSP and the underlying CD4+ T cell diversification. T follicular helper cells, CD4+ cytotoxic T cells, activated B cells, and plasma cells were found in LatY136F spleen and lung. Such cell constellation entailed all the cell types causative of human IgG4-related disease (IgG4-RD), an autoimmune and inflammatory condition with LatY136F DLSP-like histopathological manifestations. Most previously described T cell-mediated autoimmune manifestations require persistent TCR input. In contrast, following their first engagement by self-antigens, the autoreactive TCR expressed by LatY136F CD4+ T cells hand over their central role in T cell activation to CD28 costimulatory molecules. As a result, all subsequent LatY136F DLSP manifestations, including the production of autoantibodies, solely rely on CD28 engagement. Our findings elucidate the etiology of the LatY136F DLSP and qualify it as a model of IgG4-RD. Ā© 2023 Joachim et al.

    • Immunology and Microbiology
    • ,
    • Cancer Research
    A CSF-1R-blocking antibody/IL-10 fusion protein increases anti-tumor immunity by effectuating tumor-resident CD8+ TĀ cells.

    In Cell Reports Medicine on 15 August 2023 by Chang, Y. W., Hsiao, H. W., et al.

    PubMed

    Strategies to increase intratumoral concentrations of an anticancer agent are desirable to optimize its therapeutic potential when said agent is efficacious primarily within a tumor but also have significant systemic side effects. Here, we generate a bifunctional protein by fusing interleukin-10 (IL-10) to a colony-stimulating factor-1 receptor (CSF-1R)-blocking antibody. The fusion protein demonstrates significant antitumor activity in multiple cancer models, especially head and neck cancer. Moreover, this bifunctional protein not only leads to the anticipated reduction in tumor-associated macrophages but also triggers proliferation, activation, and metabolic reprogramming of CD8+ TĀ cells. Furthermore, it extends the clonotype diversity of tumor-infiltrated TĀ cells and shifts the tumor microenvironment (TME) to an immune-active state. This study suggests an efficient strategy for designing immunotherapeutic agents by fusing a potent immunostimulatory molecule to an antibody targeting TME-enriched factors. Copyright Ā© 2023 The Author(s). Published by Elsevier Inc. All rights reserved.

    • COVID-19
    SARS-CoV-2 mouse adaptation selects virulence mutations that cause TNF-driven age-dependent severe disease with human correlates.

    In Proceedings of the National Academy of Sciences of the United States of America on 8 August 2023 by Bader, S. M., Cooney, J., et al.

    PubMed

    The diversity of COVID-19 disease in otherwise healthy people, from seemingly asymptomatic infection to severe life-threatening disease, is not clearly understood. We passaged a naturally occurring near-ancestral SARS-CoV-2 variant, capable of infecting wild-type mice, and identified viral genomic mutations coinciding with the acquisition of severe disease in young adult mice and lethality in aged animals. Transcriptomic analysis of lung tissues from mice with severe disease elucidated a host antiviral response dominated mainly by interferon and IL-6 pathway activation in young mice, while in aged animals, a fatal outcome was dominated by TNF and TGF-Ī² signaling. Congruent with our pathway analysis, we showed that young TNF-deficient mice had mild disease compared to controls and aged TNF-deficient animals were more likely to survive infection. Emerging clinical correlates of disease are consistent with our preclinical studies, and our model may provide value in defining aberrant host responses that are causative of severe COVID-19.

    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Localized cytotoxic T cell-associated antigen 4 and antioxidant islet encapsulation alters macrophage signaling and induces regulatory and anergic T cells to enhance allograft survival.

    In American Journal of Transplantation : Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons on 1 April 2023 by Barra, J. M., Kozlovskaya, V., et al.

    PubMed

    The loss of functional Ī²-cell mass is a hallmark of type 1 diabetes. Islet transplantation represents a promising alternative approach, but immune-mediated graft destruction remains a major challenge. We sought to use islet encapsulation technologies to improve graft survival and function without systemic immunosuppression. We hypothesized islet encapsulation with nanothin coatings consisting of tannic acid (TA), an antioxidant; poly(N-vinylpyrrolidone) (PVPON), a biocompatible polymer; and cytotoxic T cell-associated antigen 4 immunoglobulin (CTLA-4-Ig), an inhibitory immune receptor, will elicit localized immunosuppression to prolong islet allograft function and suppress effector T cell responses. In the absence of systemic immunosuppression, we demonstrated (PVPON/TA/CTLA-4-Ig)-encapsulated NOD.Rag islet grafts maintain function significantly longer than control IgG-containing (PVPON/TA/IgG) and nonencapsulated controls after transplantation into diabetic C57BL/6 mice. This protection coincided with diminished proinflammatory macrophage responses mediated by signal transducer and activator of transcription 1 signaling, decreased proinflammatory T cell effector responses, and CTLA-4-Ig-specific concomitant increases in anergic CD4+ T cells and regulatory T cells. Our results provide evidence that conjugation of CTLA-4-Ig to (PVPON/TA) coatings can suppress T cell activation, enhance regulatory T cell populations, prolong islet allograft survival, and induce localized immunosuppression after transplantation. Copyright Ā© 2023 American Society of Transplantation & American Society of Transplant Surgeons. Published by Elsevier Inc. All rights reserved.

    • In Vivo
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    TNF hampers intestinal tissue repair in colitis by restricting IL-22 bioavailability.

    In Mucosal Immunology on 1 April 2022 by Ninnemann, J., Winsauer, C., et al.

    PubMed

    Successful treatment of chronic inflammatory diseases integrates both the cessation of inflammation and the induction of adequate tissue repair processes. Strikingly, targeting a single proinflammatory cytokine, tumor necrosis factor (TNF), induces both processes in a relevant cohort of inflammatory bowel disease (IBD) patients. However, the molecular mechanisms underlying intestinal repair following TNF blockade during IBD remain elusive. Using a novel humanized model of experimental colitis, we demonstrate that TNF interfered with the tissue repair program via induction of a soluble natural antagonist of IL-22 (IL-22Ra2; IL-22BP) in the colon and abrogated IL-22/STAT3-mediated mucosal repair during colitis. Furthermore, membrane-bound TNF expressed by T cells perpetuated colonic inflammation, while soluble TNF produced by epithelial cells (IECs) induced IL-22BP expression in colonic dendritic cells (DCs) and dampened IL-22-driven restitution of colonic epithelial functions. Finally, TNF induced IL-22BP expression in human monocyte-derived DCs and levels of IL22-BP correlated with TNF in sera of IBD patients. Thus, our data can explain how anti-TNF therapy induces mucosal healing by increasing IL-22 availability and implicates new therapeutic opportunities for IBD. Ā© 2022. The Author(s).

    • In Vivo
    • ,
    • IHC
    • ,
    • Mus musculus (House mouse)
    • ,
    • Cancer Research
    Preclinical characterization of bemarituzumab, an anti-FGFR2b antibody for the treatment of cancer.

    In MAbs on 2 November 2021 by Xiang, H., Chan, A. G., et al.

    PubMed

    Bemarituzumab (FPA144) is a first-in-class, humanized, afucosylated immunoglobulin G1 monoclonal antibody (mAb) directed against fibroblast growth factor receptor 2b (FGFR2b) with two mechanisms of action against FGFR2b-overexpressing tumors: inhibition of FGFR2b signaling and enhanced antibody-dependent cell-mediated cytotoxicity (ADCC). Bemarituzumab is being developed as a cancer therapeutic, and we summarize here the key nonclinical data that supported moving it into clinical trials. Bemarituzumab displayed sub-nanomolar cross-species affinity for FGFR2b receptors, with >20-fold enhanced binding affinity to human Fc gamma receptor IIIa compared with the fucosylated version. In vitro, bemarituzumab induced potent ADCC against FGFR2b-expressing tumor cells, and inhibited FGFR2 phosphorylation and proliferation of SNU-16 gastric cancer cells in a concentration-dependent manner. In vivo, bemarituzumab inhibited tumor growth through inhibition of the FGFR2b pathway and/or ADCC in mouse models. Bemarituzumab demonstrated enhanced anti-tumor activity in combination with chemotherapy, and due to bemarituzumab-induced natural killer cell-dependent increase in programmed death-ligand 1, also resulted in enhanced anti-tumor activity when combined with an anti-programmed death-1 antibody. Repeat-dose toxicity studies established the highest non-severely-toxic dose at 1 and 100 mg/kg in rats and cynomolgus monkeys, respectively. In pharmacokinetic (PK) studies, bemarituzumab exposure increase was greater than dose-proportional, with the linear clearance in the expected dose range for a mAb. The PK data in cynomolgus monkeys were used to project bemarituzumab linear PK in humans, which were consistent with the observed human Phase 1 data. These key nonclinical studies facilitated the successful advancement of bemarituzumab into the clinic.

    • Cell Culture
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Niche-specific MHC II and PD-L1 regulate CD4+CD8Ī±Ī±+ intraepithelial lymphocyte differentiation.

    In The Journal of Experimental Medicine on 5 April 2021 by Moon, S., Park, Y., et al.

    PubMed

    Conventional CD4+ T cells are differentiated into CD4+CD8Ī±Ī±+ intraepithelial lymphocytes (IELs) in the intestine; however, the roles of intestinal epithelial cells (IECs) are poorly understood. Here, we showed that IECs expressed MHC class II (MHC II) and programmed death-ligand 1 (PD-L1) induced by the microbiota and IFN-Ī³ in the distal part of the small intestine, where CD4+ T cells were transformed into CD4+CD8Ī±Ī±+ IELs. Therefore, IEC-specific deletion of MHC II and PD-L1 hindered the development of CD4+CD8Ī±Ī±+ IELs. Intracellularly, PD-1 signals supported the acquisition of CD8Ī±Ī± by down-regulating the CD4-lineage transcription factor, T helper-inducing POZ/KrĆ¼ppel-like factor (ThPOK), via the Src homology 2 domain-containing tyrosine phosphatase (SHP) pathway. Our results demonstrate that noncanonical antigen presentation with cosignals from IECs constitutes niche adaptation signals to develop tissue-resident CD4+CD8Ī±Ī±+ IELs. Ā© 2021 Moon et al.

    • In Vivo
    • ,
    • Mus musculus (House mouse)
    • ,
    • Cancer Research
    • ,
    • Immunology and Microbiology
    Inhibition of MICA and MICB Shedding Elicits NK-Cell-Mediated Immunity against Tumors Resistant to Cytotoxic T Cells.

    In Cancer Immunology Research on 1 June 2020 by Ferrari de Andrade, L., Kumar, S., et al.

    PubMed

    Resistance to cytotoxic T cells is frequently mediated by loss of MHC class I expression or IFNĪ³ signaling in tumor cells, such as mutations of B2M or JAK1 genes. Natural killer (NK) cells could potentially target such resistant tumors, but suitable NK-cell-based strategies remain to be developed. We hypothesized that such tumors could be targeted by NK cells if sufficient activating signals were provided. Human tumors frequently express the MICA and MICB ligands of the activating NKG2D receptor, but proteolytic shedding of MICA/B represents an important immune evasion mechanism in many human cancers. We showed that B2M- and JAK1-deficient metastases were targeted by NK cells following treatment with a mAb that blocks MICA/B shedding. We also demonstrated that the FDA-approved HDAC inhibitor panobinostat and a MICA/B antibody acted synergistically to enhance MICA/B surface expression on tumor cells. The HDAC inhibitor enhanced MICA/B gene expression, whereas the MICA/B antibody stabilized the synthesized protein on the cell surface. The combination of panobinostat and the MICA/B antibody reduced the number of pulmonary metastases formed by a human melanoma cell line in NOD/SCID gamma mice reconstituted with human NK cells. NK-cell-mediated immunity induced by a mAb specific for MICA/B, therefore, provides an opportunity to target tumors with mutations that render them resistant to cytotoxic T cells. Ā©2020 American Association for Cancer Research.

    • In Vivo
    • ,
    • Mus musculus (House mouse)
    • ,
    • Cancer Research
    Therapeutic Targeting of CD146/MCAM Reduces Bone Metastasis in Prostate Cancer.

    In Molecular Cancer Research on 1 May 2019 by Zoni, E., Astrologo, L., et al.

    PubMed

    Prostate Cancer is the most common cancer and the second leading cause of cancer-related death in males. When prostate cancer acquires castration resistance, incurable metastases, primarily in the bone, occur. The aim of this study is to test the applicability of targeting melanoma cell adhesion molecule (MCAM; CD146) with a mAb for the treatment of lytic prostate cancer bone metastasis. We evaluated the effect of targeting MCAM using in vivo preclinical bone metastasis models and an in vitro bone niche coculture system. We utilized FACS, cell proliferation assays, and gene expression profiling to study the phenotype and function of MCAM knockdown in vitro and in vivo. To demonstrate the impact of MCAM targeting and therapeutic applicability, we employed an anti-MCAM mAb in vivo. MCAM is elevated in prostate cancer metastases resistant to androgen ablation. Treatment with DHT showed MCAM upregulation upon castration. We investigated the function of MCAM in a direct coculture model of human prostate cancer cells with human osteoblasts and found that there is a reduced influence of human osteoblasts on human prostate cancer cells in which MCAM has been knocked down. Furthermore, we observed a strongly reduced formation of osteolytic lesions upon bone inoculation of MCAM-depleted human prostate cancer cells in animal model of prostate cancer bone metastasis. This phenotype is supported by RNA sequencing (RNA-seq) analysis. Importantly, in vivo administration of an anti-MCAM human mAb reduced the tumor growth and lytic lesions. These results highlight the functional role for MCAM in the development of lytic bone metastasis and suggest that MCAM is a potential therapeutic target in prostate cancer bone metastasis. IMPLICATIONS: This study highlights the functional application of an anti-MCAM mAb to target prostate cancer bone metastasis. Ā©2019 American Association for Cancer Research.

    • Immunology and Microbiology
    Regulation of autoimmune germinal center reactions in lupus-prone BXD2 mice by follicular helper T cells.

    In PLoS ONE on 15 March 2015 by Kim, Y. U., Lim, H., et al.

    PubMed

    BXD2 mice spontaneously develop autoantibodies and subsequent glomerulonephritis, offering a useful animal model to study autoimmune lupus. Although initial studies showed a critical contribution of IL-17 and Th17 cells in mediating autoimmune B cell responses in BXD2 mice, the role of follicular helper T (Tfh) cells remains incompletely understood. We found that both the frequency of Th17 cells and the levels of IL-17 in circulation in BXD2 mice were comparable to those of wild-type. By contrast, the frequency of PD-1+ CXCR5+ Tfh cells was significantly increased in BXD2 mice compared with wild-type mice, while the frequency of PD-1+ CXCR5+ Foxp3+ follicular regulatory T (Tfr) cells was reduced in the former group. The frequency of Tfh cells rather than that of Th17 cells was positively correlated with the frequency of germinal center B cells as well as the levels of autoantibodies to dsDNA. More importantly, CXCR5+ CD4+ T cells isolated from BXD2 mice induced the production of IgG from naĆÆve B cells in an IL-21-dependent manner, while CCR6+ CD4+ T cells failed to do so. These results together demonstrate that Tfh cells rather than Th17 cells contribute to the autoimmune germinal center reactions in BXD2 mice.