p53 represses class switch recombination to IgG2a through its antioxidant function

UMMS Affiliation

Department of Microbiology and Physiological Systems; Department of Pathology; Department of Cancer Biology; Program in Gene Function and Expression; Program in Molecular Medicine; Program in Immunology and Virology

Publication Date


Document Type



Animals; Antioxidants; Blotting, Western; Cell Separation; Cytidine Deaminase; DNA Breaks, Double-Stranded; Flow Cytometry; Immunoglobulin Class Switching; Immunoglobulin G; Mice; Mice, Inbred C57BL; Mice, Knockout; Reactive Oxygen Species; Reverse Transcriptase Polymerase Chain Reaction; Tumor Suppressor Protein p53


Genetics and Genomics | Immunology and Infectious Disease


Ig class switch recombination (CSR) occurs in activated mature B cells, and causes an exchange of the IgM isotype for IgG, IgE, or IgA isotypes, which increases the effectiveness of the humoral immune response. DNA ds breaks in recombining switch (S) regions, where CSR occurs, are required for recombination. Activation-induced cytidine deaminase initiates DNA ds break formation by deamination of cytosines in S regions. This reaction requires reactive oxygen species (ROS) intermediates, such as hydroxyl radicals. In this study we show that the ROS scavenger N-acetylcysteine inhibits CSR. We also demonstrate that IFN-gamma treatment, which is used to induce IgG2a switching, increases intracellular ROS levels, and activates p53 in switching B cells, and show that p53 inhibits IgG2a class switching through its antioxidant-regulating function. Finally, we show that p53 inhibits DNA breaks and mutations in S regions in B cells undergoing CSR, suggesting that p53 inhibits the activity of activation-induced cytidine deaminase.

DOI of Published Version



J Immunol. 2010 Jun 1;184(11):6177-87. doi: 10.4049/jimmunol.0904085. Link to article on publisher's site

Journal/Book/Conference Title

Journal of immunology (Baltimore, Md. : 1950)

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Link to Article in PubMed

PubMed ID