Clonal instability of V region hypermutation in the Ramos Burkitt's lymphoma cell line

W. Zhang, P. D. Bardwell, C. J. Woo, V. Poltoratsky, Matthew D. Scharff, A. Martin

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

Affinity maturation of the humoral immune response is caused by single base changes that are introduced into the V regions of the Ig genes during a brief period of B cell differentiation. It has recently become possible to study V region mutation in some human Burkitt's lymphoma cell lines that mutate their V regions and express surface markers that suggest they arose from the malignant transformation of germinal center B cells. Ramos Burkitt's cells constitutively mutate their V regions at a rate of ∼2 × 10-5 mutations/bp/generation. However, the sequencing of unselected V regions suggested that our Ramos cell line was progressively losing its ability to undergo V region hypermutation. To accurately quantify this process, subclones with different nonsense mutations in the μ heavy chain V region were identified. Reversion analysis and sequencing of unselected V regions were used to examine the clonal stability of V region hypermutation. Even after only 1 month in culture, stable and unstable subclones could be identified. The identification of mutating and non-mutating subclones of Ramos provided a unique opportunity to identify factors involved in the mutational process. Differential gene expression between mutating and non-mutating Ramos clones was examined by RT-PCR and cDNA microarray analyses. We found that the expression of activation-induced cytidine deaminase (AID), a putative cytidine deaminase, correlated with mutation rates in Ramos subclones. These results suggest that the hypermutation phenotype is inherently unstable in Ramos and that long culture periods favor outgrowth of non-mutating cells that express lower levels of AID.

Original languageEnglish (US)
Pages (from-to)1175-1184
Number of pages10
JournalInternational Immunology
Volume13
Issue number9
StatePublished - 2001

Fingerprint

Burkitt Lymphoma
B-Lymphocytes
Cytidine Deaminase
Cell Line
Immunoglobulin Genes
Mutation
Germinal Center
Nonsense Codon
Mutation Rate
Microarray Analysis
Humoral Immunity
Oligonucleotide Array Sequence Analysis
Cell Differentiation
Clone Cells
Phenotype
Gene Expression
Polymerase Chain Reaction
AICDA (activation-induced cytidine deaminase)

Keywords

  • Antibody
  • B lymphocytes
  • Burkitt's lymphoma
  • Somatic mutation

ASJC Scopus subject areas

  • Immunology

Cite this

Zhang, W., Bardwell, P. D., Woo, C. J., Poltoratsky, V., Scharff, M. D., & Martin, A. (2001). Clonal instability of V region hypermutation in the Ramos Burkitt's lymphoma cell line. International Immunology, 13(9), 1175-1184.

Clonal instability of V region hypermutation in the Ramos Burkitt's lymphoma cell line. / Zhang, W.; Bardwell, P. D.; Woo, C. J.; Poltoratsky, V.; Scharff, Matthew D.; Martin, A.

In: International Immunology, Vol. 13, No. 9, 2001, p. 1175-1184.

Research output: Contribution to journalArticle

Zhang, W, Bardwell, PD, Woo, CJ, Poltoratsky, V, Scharff, MD & Martin, A 2001, 'Clonal instability of V region hypermutation in the Ramos Burkitt's lymphoma cell line', International Immunology, vol. 13, no. 9, pp. 1175-1184.
Zhang, W. ; Bardwell, P. D. ; Woo, C. J. ; Poltoratsky, V. ; Scharff, Matthew D. ; Martin, A. / Clonal instability of V region hypermutation in the Ramos Burkitt's lymphoma cell line. In: International Immunology. 2001 ; Vol. 13, No. 9. pp. 1175-1184.
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