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Location and length distribution of somatic hypermutation-associated DNA insertions and deletions reveals regions of antibody structural plasticity. Genes Immun 2012; 13:523-9. [PMID: 22717702 PMCID: PMC3449029 DOI: 10.1038/gene.2012.28] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Following the initial diversity generated by V(D)J recombination, somatic hypermutation is the principal mechanism for producing further antibody repertoire diversity in antigen-experienced B cells. While somatic hypermutation typically results in single nucleotide substitutions, the infrequent incorporation of genetic insertions and deletions has also been associated with the somatic hypermutation process. We used high throughput antibody sequencing to determine the sequence of thousands of antibody genes containing somatic hypermutation-associated insertions and deletions (SHA indels), which revealed significant differences between the location of SHA indels and somatic mutations. Further, we identified a cluster of insertions and deletions in the antibody framework 3 region which corresponds to the hypervariable region 4 (HV4) in T cell receptors. We propose that this HV4-like region, identified by SHA indel analysis, represents a region of under-appreciated affinity maturation potential. Finally, through analysis of both location and length distribution of SHA indels, we have determined regions of structural plasticity within the antibody protein.
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2
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Sozzi E, Amato T, Sahota SS, Nuti S, Raspadori D, Sicuranza A, Cencini E, Tosi P, Lauria F, Forconi F. Lack of allelic exclusion by secondary rearrangements of tumour B-cell receptor light chains in hairy cell leukaemia. Hematol Oncol 2011; 29:31-7. [PMID: 20658474 DOI: 10.1002/hon.952] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Analyses of the tumour immunoglobulin (Ig) gene (IG) heavy (H) and light chains show heterogeneity of mutational status, but reveal common features of ongoing IGH isotype-switching with multiple IGH isotype expression and preference of IG lambda (IGL) light chain with selective use of IGLJ3. Phenotypic and immunogenetic analyses were performed in a series of 105 HCL patients to estimate prevalence of multiple IG light chain expression by the tumour cells. By phenotype, 3/105 HCL (2.9%) expressed double tumour-related Ig kappa (K) and L light chain proteins. By immunogenetic analysis, functional mutated double IGK(I) /IGK(II) , IGK(I) /IGL(I) and IGL(I) /IGL(II) transcripts were cloned and sequenced in 3/71 (4.2%) HCL. These latter three HCL expressed multiple IGH isotypes with mutated IGHVDJ rearrangements at the time of AID transcript expression. Most interestingly, the three cases had reinduced RAG1 transcript. In the double IGL expresser, single-cell analysis documented co-expression of the tumour-related IGLs in 5/6 cells (83%). In the IGK/IGL co-expresser, evidence of surface IgK/IgL isotype proteins confirmed functionality of the tumour-derived transcripts. The evidence of double light chain expression in single HCs and the new observation of RAG re-induction suggest ongoing selective influences on the BCR that may promote or maintain the HCL clone in the periphery.
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Affiliation(s)
- Elisa Sozzi
- Sezione and Unità di Ematologia, Università di Siena & AOUS, Italy
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3
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Crystal structure of PG16 and chimeric dissection with somatically related PG9: structure-function analysis of two quaternary-specific antibodies that effectively neutralize HIV-1. J Virol 2010; 84:8098-110. [PMID: 20538861 DOI: 10.1128/jvi.00966-10] [Citation(s) in RCA: 183] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV-1 resists neutralization by most antibodies. Two somatically related human antibodies, PG9 and PG16, however, each neutralize 70 to 80% of circulating HIV-1 isolates. Here we present the structure of the antigen-binding fragment of PG16 in monoclinic and orthorhombic lattices at 2.4 and 4.0 A, respectively, and use a combination of structural analysis, paratope dissection, and neutralization assessment to determine the functional relevance of three unusual PG9/PG16 features: N-linked glycosylation, extensive affinity maturation, and a heavy chain-third complementarity-determining region (CDR H3) that is one of the longest observed in human antibodies. Glycosylation extended off the side of the light chain variable domain and was not required for neutralization. The CDR H3 formed an axe-shaped subdomain, which comprised 42% of the CDR surface, with the axe head looming approximately 20 A above the other combining loops. Comprehensive sets of chimeric swaps between PG9 and PG16 of light chain, heavy chain, and CDR H3 were employed to decipher structure-function relationships. Chimeric swaps generally complemented functionally, with differences in PG9/PG16 neutralization related primarily to residue differences in CDR H3. Meanwhile, chimeric reversions to genomic V genes showed isolate-dependent effects, with affinity maturation playing a significant role in augmenting neutralization breadth (P = 0.036) and potency (P < 0.0001). The structural and functional details of extraordinary CDR H3 and extensive affinity maturation provide insights into the neutralization mechanism of and the elicitation pathway for broadly neutralizing antibodies like PG9 and PG16.
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Kobrin C, Cha SC, Qin H, Raffeld M, Fend F, Quintanilla-Martinez L, Grove S, Jaffe ES, Kwak LW. Molecular analysis of light-chain switch and acute lymphoblastic leukemia transformation in two follicular lymphomas: Implications for lymphomagenesis. Leuk Lymphoma 2009; 47:1523-34. [PMID: 16966263 DOI: 10.1080/10428190600612909] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
We observed novel transformations of follicular lymphoma (FL), first, a switch in immunoglobulin (Ig) light chain, and second, transformation of FL to acute lymphoblastic leukemia (ALL). Each set of tumors shared a common clonal origin, as demonstrated by expression of identical, unique CDR IIIH sequences, shared somatic mutations in JH, and identical bcl-2 translocation breakpoints of microdissected ALL cells. Molecular analysis of lambda V-gene expression demonstrated lambda-bearing cells in the original kappa tumor, while expansion of the lambda subclone at relapse occurred after active immunotherapy targeting the Ig receptor. These exceptional cases are compatible with a more contemporary model of lymphomagenesis in which critical events originate from genetic mechanisms which normally occur in germinal center (GC) B cells and challenge the current paradigm of parallel generation of subclones from an early, pre-GC precursor. It is also possible that the outgrowth of these variants was a consequence of immunoselection.
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Affiliation(s)
- Carol Kobrin
- Intramural Research Support Program, SAIC-Frederick, National Cancer Institute-Frederick Cancer Research and Development Center, USA
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5
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Tian C, Luskin GK, Dischert KM, Higginbotham JN, Shepherd BE, Crowe JE. Evidence for preferential Ig gene usage and differential TdT and exonuclease activities in human naïve and memory B cells. Mol Immunol 2006; 44:2173-83. [PMID: 17196657 PMCID: PMC1859862 DOI: 10.1016/j.molimm.2006.11.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2006] [Revised: 11/13/2006] [Accepted: 11/18/2006] [Indexed: 11/20/2022]
Abstract
Memory B cells and the antibodies they encode are important for protective immunity against infectious pathogens. Characterization of naïve and memory B cell antibody repertoires will elucidate the molecular basis for the generation of antibody diversity in human B cells and the optimization of antibody structures that bind microbial antigens. In this study we aimed to investigate the influence of antigenic selection on the antibody genes of the two CD27+ memory B cell subsets, comparing them with the naïve repertoire in CD27- cells. We analyzed and compared the Ig heavy chain gene transcripts in three recently defined circulating naïve and memory B cell subsets (CD19+IgD+CD27- [naïve], CD19+IgD+CD27+ [un-class-switched memory] or CD19+IgD- CD27+ [class-switched memory]) at the single cell level. We found similar biased patterns of variable, diversity and joining heavy chain gene usages in all three groups of cells. CD19+IgD+CD27+ memory B cells harbored as diverse an antibody gene repertoire as CD19+IgD-CD27+ memory B cells. Interestingly, CD19+IgD+CD27+ memory B cells possessed a lower frequency of somatic mutations, a higher incidence of exonuclease activity at the 3' end of D regions, and a lower frequency of N and P nucleotide additions at both VH-D and D-JH junctions of CDR3 regions compared to CD19+IgD-CD27+ memory B cells. These data suggest distinct functional mechanisms underlying selection of this unique subset of un-class-switched memory B cells.
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Affiliation(s)
- Cuixia Tian
- Department of Pediatrics, Vanderbilt University Medical Center, 21st Avenue South, Nashville, Tennessee, 37232
| | - Grace K. Luskin
- Department of Pediatrics, Vanderbilt University Medical Center, 21st Avenue South, Nashville, Tennessee, 37232
| | - Kevin M. Dischert
- Department of Pediatrics, Vanderbilt University Medical Center, 21st Avenue South, Nashville, Tennessee, 37232
| | - James N. Higginbotham
- Department of Pediatrics, Vanderbilt University Medical Center, 21st Avenue South, Nashville, Tennessee, 37232
| | - Bryan E. Shepherd
- Department of Biostatistics, Vanderbilt University Medical Center, 21st Avenue South, Nashville, Tennessee, 37232
| | - James E. Crowe
- Department of Pediatrics, Vanderbilt University Medical Center, 21st Avenue South, Nashville, Tennessee, 37232
- Department of Microbiology and Immunology, Vanderbilt University Medical Center, 21st Avenue South, Nashville, Tennessee, 37232
- * Corresponding author: James E. Crowe, Jr., M.D., Vanderbilt University Medical Center, Department of Pediatrics, T-2220 Medical Center North, 1161 21st Avenue South, Nashville, TN 37232-2905, USA, Tel.: (615) 343-8064, Fax: (615) 343-4456, e-mail:
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6
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Inogès S, Rodrìguez-Calvillo M, Zabalegui N, Lòpez-Dìaz de Cerio A, Villanueva H, Soria E, Suárez L, Rodríguez-Caballero A, Pastor F, García-Muñóz R, Panizo C, Pèrez-Calvo J, Melero I, Rocha E, Orfao A, Bendandi M. Clinical benefit associated with idiotypic vaccination in patients with follicular lymphoma. J Natl Cancer Inst 2006; 98:1292-301. [PMID: 16985248 DOI: 10.1093/jnci/djj358] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Follicular lymphoma is considered incurable, although cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy can induce sequential remissions. A patient's second complete response is typically shorter than that patient's first complete response. Idiotype vaccines can elicit specific immune responses and molecular remissions in patients with follicular lymphoma. However, a clinical benefit has never been formally proven. METHODS Thirty-three consecutive follicular lymphoma patients in first relapse received six monthly cycles of CHOP-like chemotherapy. Patients who achieved a second complete response were vaccinated periodically for more than 2 years with autologous lymphoma-derived idiotype protein vaccine. Specific humoral and cellular responses were assessed, and patients were followed for disease recurrence. Statistical tests were two-sided. RESULTS Idiotype vaccine could be produced for 25 patients who had a second complete response. In 20 patients (80%), a humoral (13/20) and/or a cellular (18/20) idiotype-specific response was detected. The median duration of the second complete response has not been reached, but it exceeds 33 months (range = 20+ to 51+ months). None of the 20 responders relapsed while undergoing active vaccination. All responders with enough follow-up for the comparison to be made experienced a second complete response that was statistically significantly (P<.0001) longer than both their first complete response (18 of 18 patients) and than the median duration of a CHOP-induced second complete response, i.e., 13 months (20 of 20 patients). The five nonresponders all had a second complete response that was shorter (median = 10 months; range = 8-13 months) than their first complete response (median = 17 months; range = 10-39 months). CONCLUSIONS Idiotypic vaccination induced a specific immune response in the majority of patients with follicular lymphoma. Specific immune response was associated with a dramatic and highly statistically significant increase in disease-free survival. This is the first formal demonstration of clinical benefit associated with the use of a human cancer vaccine.
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Affiliation(s)
- Susana Inogès
- Lab of Immunotherapy, Oncology Division, Center for Applied Medical Research (CIMA), Avda. Pio XII, 55, 31008 Pamplona (Navarra), Spain
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7
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Babbage G, Ottensmeier CH, Blaydes J, Stevenson FK, Sahota SS. Immunoglobulin heavy chain locus events and expression of activation-induced cytidine deaminase in epithelial breast cancer cell lines. Cancer Res 2006; 66:3996-4000. [PMID: 16618718 DOI: 10.1158/0008-5472.can-05-3704] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
When cells transform, phenotypic and genetic profiles can be dramatically altered. Nevertheless, a recent report identifying IgG in breast cancer cells was unexpected, revealing differentiation features normally associated with B lymphocytes. To extend these findings, we focused on immunoglobulin variable (V) region gene analysis using well-defined breast cancer cell lines expressing the epithelial marker, epithelial cell adhesion molecule (EpCAM). V(H) gene transcripts were identifiable by nested reverse transcription-PCR either as single or dual V, diversity (D), and joining (J) rearrangements in four of six lines, most being potentially functional. V(D)J transcripts were observed in sequential cultures, indicating stable expression. To exclude coexisting lymphocytes, each cell line was shown to be EBV negative, with CD19/CD20 and cytoplasmic/surface immunoglobulin also absent by flow cytometry. Identified V(H) transcripts were then sought in individual tumor cells, isolated as EpCAM+ single cells by flow cytometry. Importantly, in three of three selected cell lines, V(H) genes were identifiable in a significant fraction (approximately 32%) of single cells. In five of six identified V(H) genes, somatic mutations were apparent with no intraclonal variation, indicating cessation of mutational activity. V(H) transcripts were pre- and post-isotype switch, with activation of switch events evident from expressed germ-line switch transcripts in two of six lines. Strikingly, six of six cell lines expressed activation-induced cytidine deaminase (AID) essential for mutational and switch activity. These data suggest either a de novo rearrangement and modification of V(H) genes in epithelial tumor cells or assimilation of lymphocyte-derived chromatin. Constitutive AID activation in malignant epithelial cells further raises a potential for inducing aberrant mutational activity.
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Affiliation(s)
- Gavin Babbage
- Genetic Vaccine Group and Cancer Sciences Division, School of Medicine, University of Southampton, Southampton, United Kingdom
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8
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Darlow JM, Stott DI. Gene conversion in human rearranged immunoglobulin genes. Immunogenetics 2006; 58:511-22. [PMID: 16705406 DOI: 10.1007/s00251-006-0113-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 02/23/2006] [Accepted: 03/16/2006] [Indexed: 11/26/2022]
Abstract
Over the past 20 years, many DNA sequences have been published suggesting that all or part of the V(H) segment of a rearranged immunoglobulin gene may be replaced in vivo. Two different mechanisms appear to be operating. One of these is very similar to primary V(D)J recombination, involving the RAG proteins acting upon recombination signal sequences, and this has recently been proven to occur. Other sequences, many of which show partial V(H) replacements with no addition of untemplated nucleotides at the V(H)-V(H) joint, have been proposed to occur by an unusual RAG-mediated recombination with the formation of hybrid (coding-to-signal) joints. These appear to occur in cells already undergoing somatic hypermutation in which, some authors are convinced, RAG genes are silenced. We recently proposed that the latter type of V(H) replacement might occur by homologous recombination initiated by the activity of AID (activation-induced cytidine deaminase), which is essential for somatic hypermutation and gene conversion. The latter has been observed in other species, but not in human Ig genes, so far. In this paper, we present a new analysis of sequences published as examples of the second type of rearrangement. This not only shows that AID recognition motifs occur in recombination regions but also that some sequences show replacement of central sections by a sequence from another gene, similar to gene conversion in the immunoglobulin genes of other species. These observations support the proposal that this type of rearrangement is likely to be AID-mediated rather than RAG-mediated and is consistent with gene conversion.
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Affiliation(s)
- John M Darlow
- Department of Immunology, Level 4, Glasgow Biomedical Research Centre, 120 University Place, Glasgow, G12 8TA, UK.
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Yáñez R, Barrios Y, Cabrera R, Díaz-Espada F. Intraclonal Variability of VH Genes in Follicular Lymphoma Patients Who Have Received Anti-Idiotypic Immunotherapy. J Immunother 2006; 29:61-6. [PMID: 16365601 DOI: 10.1097/01.cji.0000182270.66506.e1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Subclonal heterogeneity can affect idiotypic determinants present in the clonotypic immunoglobulin of B-cell follicular lymphomas (FLs) and may limit the effect of antilymphoma treatments performed by immunization of patients with their own tumor-associated idiotypic immunoglobulin. Idiotype-secreting hybridomas were obtained by fusion of tumor cells from 5 patients with FL, and the K6H6/B5 human heteromyeloma and rearranged VH genes from tumor samples and hybridomas were amplified, cloned, and sequenced. Sequences were aligned with germline genes and somatic mutations, intraclonal heterogeneity and genealogic relations of the B-cell clones in the different biopsy specimens were determined. The VH sequence of the progenitor clone was determined in samples of the tumoral population. Further diversification resulted in the presence of 2 to 6 subclones in 4 of the 5 samples studied. Only in 1 patient did the hypermutation mechanism introduce differences among most of the potential idiotopes present in individual subclones. The VH sequence of the hybridoma that provided the idiotypic-vaccine was identified in one of the tumor subclones in all cases. No relapse has been demonstrated in 3 of the 4 vaccinated patients (follow-up: 29-103 months). We conclude that despite potential differences in the idiotypic region expressed by individual tumor cells, at least some potential idiotopes may be preserved among all the tumor subclones in most cases studied. All vaccinated patients developed immune responses against the autologous tumor idiotypic immunoglobulin. Polyclonal anti-idiotypic immune responses induced with a vaccine obtained from 1 hybridoma may be effective against all the idiotypic variants present in the tumor population.
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Affiliation(s)
- Rosa Yáñez
- Department of Immunology, Hospital Clínica Puerta de Hierro, Madrid, Spain
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10
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Neelapu SS, Kwak LW, Kobrin CB, Reynolds CW, Janik JE, Dunleavy K, White T, Harvey L, Pennington R, Stetler-Stevenson M, Jaffe ES, Steinberg SM, Gress R, Hakim F, Wilson WH. Vaccine-induced tumor-specific immunity despite severe B-cell depletion in mantle cell lymphoma. Nat Med 2005; 11:986-91. [PMID: 16116429 DOI: 10.1038/nm1290] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 07/26/2005] [Indexed: 11/08/2022]
Abstract
The role of B cells in T-cell priming is unclear, and the effects of B-cell depletion on immune responses to cancer vaccines are unknown. Although results from some mouse models suggest that B cells may inhibit induction of T cell-dependent immunity by competing with antigen-presenting cells for antigens, skewing T helper response toward a T helper 2 profile and/or inducing T-cell tolerance, results from others suggest that B cells are necessary for priming as well as generation of T-cell memory. We assessed immune responses to a well-characterized idiotype vaccine in individuals with severe B-cell depletion but normal T cells after CD20-specific antibody-based chemotherapy of mantle cell lymphoma in first remission. Humoral antigen- and tumor-specific responses were detectable but delayed, and they correlated with peripheral blood B-cell recovery. In contrast, vigorous CD4(+) and CD8(+) antitumor type I T-cell cytokine responses were induced in most individuals in the absence of circulating B cells. Analysis of relapsing tumors showed no mutations or change in expression of target antigen to explain escape from therapy. These results show that severe B-cell depletion does not impair T-cell priming in humans. Based on these results, it is justifiable to administer vaccines in the setting of B-cell depletion; however, vaccine boosts after B-cell recovery may be necessary for optimal humoral responses.
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Affiliation(s)
- Sattva S Neelapu
- Experimental and Transplantation Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 10 Center Drive, Bethesda, Maryland 20892, USA
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11
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Abstract
Examples suggesting that all or part of the V(H) segment of a rearranged V(H)DJ(H) may be replaced by all or part of another V(H) have been appearing since the 1980s. Evidence has been presented of two rather different types of replacement. One of these has gained acceptance and has now been clearly demonstrated to occur. The other, proposed more recently, has not yet gained general acceptance because the same effect can be produced by polymerase chain reaction artefact. We review both types of replacement including a critical examination of evidence for the latter. The first type involves RAG proteins and recombination signal sequences (RSS) and occurs in immature B cells. The second was also thought to be brought about by RAG proteins and RSS. However, it has been reported in hypermutating cells which are not thought to express RAG proteins but in which activation-induced cytidine deaminase (AID) has recently been shown to initiate homologous recombination. Re-examination of the published sequences reveals AID target sites in V(H)-V(H) junction regions and examples that resemble gene conversion.
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Affiliation(s)
- John M Darlow
- Department of Immunology, Division of Immunology, Infection and Inflammation, University of Glasgow, Western Infirmary, Glasgow, UK.
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12
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Hardianti MS, Tatsumi E, Syampurnawati M, Furuta K, Suzuki A, Saigo K, Kawano S, Takenokuchi M, Kumagai S, Matsuo Y, Koizumi T, Takeuchi M. Presence of somatic hypermutation and activation-induced cytidine deaminase in acute lymphoblastic leukemia L2 with t(14;18)(q32;q21). Eur J Haematol 2005; 74:11-9. [PMID: 15613101 DOI: 10.1111/j.1600-0609.2004.00338.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM Acute lymphoblastic leukemia (ALL) with L2 (FAB) morphology has rarely been reported to show t(14;18)(q32;q21). We aimed to delineate the stage at which this type of ALL is derived in B-lineage differentiation. METHODS The somatic hypermutation (SHM) of the variable region of immunoglobulin heavy chain (IgV(H)) gene and the expression of terminal deoxynucleotidyl transferase (TdT), recombination-activating gene 1 and 2 (RAG-1 and -2), and activation-induced cytidine deaminase (AID) were investigated in three cell lines and two fresh samples, including a pair of matched fresh and cell line cells. RESULTS TdT, RAG-1, and RAG-2 were variably expressed. AID was expressed in four of five samples. SHM of the IgV(H) gene was found in all samples with high average frequency (11.84%) comparable with that in follicular lymphoma. Ongoing mutation was seen in two fresh samples. CONCLUSION As AID and SHM are generally regarded as properties exhibited by mature B cells, the presence of AID and SHM in this study seems to be incompatible with the general understanding of the early stage derivation of ALL in B-lineage differentiation. The results here give some insight into the relationship between disease type (ALL or lymphoma) and derivation stage, the overlapping of the early stage phenotype and the mature genomic characteristics, and the probable relationship between the mechanism of the occurrence of t(14;18)(q32;q21) and the machinery causing SHM.
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MESH Headings
- Base Sequence
- Cell Line, Tumor
- Chromosomes, Human, Pair 14/genetics
- Chromosomes, Human, Pair 18/genetics
- Cytidine Deaminase
- Cytosine Deaminase/genetics
- DNA Nucleotidylexotransferase/genetics
- DNA, Neoplasm/genetics
- DNA-Binding Proteins/genetics
- Gene Expression
- Genes, RAG-1
- Humans
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Variable Region/genetics
- Nuclear Proteins
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/enzymology
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/immunology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Neoplasm/genetics
- RNA, Neoplasm/metabolism
- Somatic Hypermutation, Immunoglobulin
- Translocation, Genetic
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Affiliation(s)
- Mardiah Suci Hardianti
- International Center for Medical Research (ICMR), Graduate School of Medicine, Kobe University, Kobe, Japan
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Hojo H, Sasaki Y, Nakamura N, Sato M, Abe M. HBL-3 cell line, derived from precursor B-cell lymphoblastic leukemia, lacks somatic hypermutation of immunoglobulin heavy chain variable region genes. Pediatr Dev Pathol 2004; 7:250-7. [PMID: 15022065 DOI: 10.1007/s10024-003-8085-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2003] [Accepted: 12/11/2003] [Indexed: 10/26/2022]
Abstract
Somatic mutation (SM) analysis provides a useful tool for understanding the stages at which neoplastic differentiate from normal B-cells. B-cell precursor neoplasms are considered to be somatically premutational. However, the variable frequency of SM of the variable region (VH) genes has been described in cases of precursor B-cell acute lymphoblastic leukemia (PB-ALL). To better characterize PB-ALL based on the differentiation stage, we investigated the SM of the VH genes expressed by tumor cells of the surface immunoglobulin (sIg)(-) HBL-3 cell line derived from childhood PB-ALL. In the HBL-3 cell line, the rearranged Ig heavy chain VH gene sequence showed no SM in the complementarity-determining regions of 1, 2, and 3, or in the framework regions of 1, 2, and 3 relative to the putative germline VH gene sequences. In addition, the VH segment of HBL-3 cells showed no intraclonal sequence heterogeneity, indicating ongoing SM. Our data demonstrated that HBL-3 cells express unmutated and developmentally regulated rearrangement of VH genes at the stage of B-cell precursor cells. HBL-3 cells, which are derived only from the sIg(-) PB-ALL, showed that SM cannot be recognized in VH genes of tumor cells before the expression of sIg.
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Affiliation(s)
- Hiroshi Hojo
- First Department of Pathology, Fukushima Medical University School of Medicine, 1 Hikariga-oka, Fukushima, 960-1295, Japan.
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14
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Kroft SH. Lymphoma transformation: genetic relatedness, stealth lymphomas, and the final frontier. Am J Clin Pathol 2001; 116:811-4. [PMID: 11764068 DOI: 10.1309/vjyb-cjel-tah2-a947] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Affiliation(s)
- S H Kroft
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas 75390-9073, USA
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