Specificity of immunoglobulin heavy chain switch correlates with activity of germline heavy chain genes prior to switching.

Stavnezer-Nordgren, Janet; Sirlin, Sonia

doi:10.1002/j.1460-2075.1986.tb04182.x

Cited by 330 publications

(180 citation statements)

References 45 publications

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“…Expression of germ-line transcripts is an essential step preceding Ig CSR (16,25). These transcripts, expressed from C H promoters, are induced in response to stimulation by Th1-or Th2-type cytokines (9).…”

Section: Transcription At Multiple Ch Loci Precedes Csr In Individualmentioning

confidence: 99%

Tracking germinal center B cells expressing germ-line immunoglobulin γ1 transcripts by conditional gene targeting

Casola

Cattoretti

Uyttersprot

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

207

266

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Germinal centers (GCs) represent the main sites for the generation of high-affinity, class-switched antibodies during T cell-dependent antibody responses. To study gene function specifically in GC B cells, we generated Cγ1-cre mice in which the expression of Cre recombinase is induced by transcription of the Ig γ1 constant region gene segment (Cγ1). In these mice, Cre-mediated recombination at the fas , Ig β, IgH , and Rosa26 loci occurred in GC B cells as early as 4 days after immunization with T cell-dependent antigens and involved >85% of GC B cells at the peak of the GC reaction. Less than 2% of IgM + B cells showed Cre-mediated recombination. These cells carried few Ig somatic mutations, expressed germ-line Cγ1- and activation-induced cytidine deaminase-specific transcripts and likely include GC B cell founders and/or plasma cell precursors. Cre-mediated recombination involved most IgG1, but also a fraction of IgG3-, IgG2a-, IgG2b-, and IgA-expressing GC and post-GC B cells. This result indicates that a GC B cell can transcribe more than one downstream C H gene before undergoing class switch recombination. The efficient induction of Cre expression in GC B cells makes the Cγ1-cre allele a powerful tool for the genetic analysis of these cells, as well as, in combination with a suitable marker for Cre-mediated recombination, the tracking of class-switched memory B and plasma cells in vivo . To expedite the genetic analysis of GC B cells, we have established Cγ1-cre F 1 embryonic stem cells, allowing further rounds of gene targeting and the cloning of compound mutants by tetraploid embryo complementation.

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Section: Transcription At Multiple Ch Loci Precedes Csr In Individualmentioning

confidence: 99%

Tracking germinal center B cells expressing germ-line immunoglobulin γ1 transcripts by conditional gene targeting

Casola

Cattoretti

Uyttersprot

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

207

266

View full text Add to dashboard Cite

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“…Finally, the IgG 1 and IgG 3 production-inducing capacity of IL-21 is not related to the origin of the B cells, because production of both isotypes was observed in cultures of PBMC, as well as anti-CD40 mAb-activated purified peripheral blood-derived B cells, in the presence of this cytokine (data not shown). The appearance of small C H -specific germline RNA transcripts is considered to be an obligatory event, preceding isotype switching in both mouse and human B cells (4,17). Indeed, C␥1 and C␥3 sterile transcripts were detectable in B cells that had been stimulated with anti-CD40 mAb and rIL-21 (Fig.…”

Section: Resultsmentioning

confidence: 99%

Cutting Edge: IL-21 Is a Switch Factor for the Production of IgG1 and IgG3 by Human B Cells

Pène

Gauchat

Lécart

et al. 2004

The Journal of Immunology

279

211

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IL-21 is a cytokine that regulates the activation of T and NK cells and promotes the proliferation of B cells activated via CD40. In this study, we show that rIL-21 strongly induces the production of all IgG isotypes by purified CD19+ human spleen or peripheral blood B cells stimulated with anti-CD40 mAb. Moreover, it was found to specifically induce the production of IgG1 and IgG3 by CD40-activated CD19+CD27− naive human B cells. Although stimulation of CD19+ B cells via CD40 alone induced γ1 and γ3 germline transcripts, as well as the expression of activation-induced cytidine deaminase, only stimulation with both anti-CD40 mAb and rIL-21 resulted in the production of Sγ/Sμ switch circular DNA. These results show that IL-21, in addition to promoting growth and differentiation of committed B cells, is a specific switch factor for the production of IgG1 and IgG3.

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“…DNA lesions associated with CSR would be expected to form after initiation of germline transcription and before expression of mature switch transcripts 17,18 . To determine when IgH-associated Nbs1/ γ-H2AX foci appear relative to these events, we assayed germline Ig1 transcription (Iγ1-Cγ1), mature IgG1 transcripts, Sμ-Sγ1 DNA rearrangements, and surface IgG1 expression (Fig.…”

Section: Hhs Public Accessmentioning

confidence: 99%

AID is required to initiate Nbs1/γ-H2AX focus formation and mutations at sites of class switching

Petersen

Casellas

Reina‐San‐Martin

et al. 2001

Nature

460

438

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Class switch recombination (CSR) is a region-specific DNA recombination reaction that replaces one immunoglobulin heavy-chain constant region (CH) gene with another. This enables a single variable (V) region gene to be used in conjunction with different downstream CH genes, each having a unique biological activity. The molecular mechanisms that mediate CSR have not been defined, but activation-induced cytidine deaminase (AID), a putative RNA-editing enzyme, is required for this reaction 1 . Here we report that the Nijmegen breakage syndrome protein (Nbs1) and phosphorylated H2A histone family member X (γ-H2AX, also known as γ-H2afx), which facilitate DNA double-strand break (DSB) repair 2-4 , form nuclear foci at the CH region in the G1 phase of the cell cycle in cells undergoing CSR, and that switching is impaired in H2AX -/-mice. Localization of Nbs1 and γ-H2AX to the IgH locus during CSR is dependent on AID. In addition, AID is required for induction of switch region (Sμ)-specific DNA lesions that precede CSR. These results place AID function upstream of the DNA modifications that initiate CSR.Correspondence and requests for materials should be addressed to A.N. (andre_nussenzweig@nih.gov) or M.C.N. (nussen@mail.rockefeller.edu).. Supplementary Information accompanies the paper on Nature's website (http://www.nature.com). Competing interests statementThe authors declare that they have no competing financial interests. To determine whether DNA repair factors associate with DSBs at the switch regions, we first examined the intracellular localization of γ-H2AX, Nbs1, Rad51 and Brca1 in activated B cells by immunofluorescence. Brca1 and Rad51 are required for homologous recombination, the Mre11-Rad50-Nbs1 complex has been implicated in both homologous recombination and non-homologous end-joining (NHEJ), and γ-H2AX is critical for recruiting these repair factors to DSBs 6 and facilitates NHEJ in Saccharomyces cerevisiae 4 . All four proteins showed diffuse nuclear staining in most of the resting B cells from C57BL/6 wild-type mice. High local concentrations of these factors (nuclear foci) were detected in a very small percentage of cells (<5%), which increased significantly when the cells were stimulated to undergo CSR in vitro with lipopolysaccharide (LPS) and interleukin (IL)-4 (Fig. 1a). After 3 days of stimulation, 37% of the B cells contained discrete Brca1 foci (12 ± 6 per cell) and 43% contained Rad51 foci (7 ± 3 per cell), consistent with previous results 7 ; the remaining cells exhibited a weak, diffuse pattern of nuclear staining (Fig. 1a). Many of the stimulated B cells also formed Nbs1 foci (32% contained, on average, 3 ± 2 per cell) and γ-H2AX foci (40% contained, on average, 4.5 ± 3 per cell). To determine which of these repair factors are co-localized in activated B cells, we performed two colour immunofluoresence experiments (Fig. 1b). Only 20% of the cells that contained Rad51 and Nbs1 (n = 687) or Brca1 and Nbs1 foci (n = 431) exhibited co-localization. In contrast, γ-H2AX foci co-localiz...

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Specificity of immunoglobulin heavy chain switch correlates with activity of germline heavy chain genes prior to switching.

Cited by 330 publications

References 45 publications

Tracking germinal center B cells expressing germ-line immunoglobulin γ1 transcripts by conditional gene targeting

Tracking germinal center B cells expressing germ-line immunoglobulin γ1 transcripts by conditional gene targeting

Cutting Edge: IL-21 Is a Switch Factor for the Production of IgG1 and IgG3 by Human B Cells

AID is required to initiate Nbs1/γ-H2AX focus formation and mutations at sites of class switching

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