Most chromosomal t(8;14) translocations in sporadic Burkitt lymphomas (BL) are mediated by immunoglobulin class switch recombination (CSR), yet all tumors express IgM, suggesting an incomplete or exclusively monoallelic CSR event. We studied the exact configuration of both the nontranslocated IGH allele and the MYC/IGH breakpoint by applying a combination of low- and high-resolution methods (in...

Small resting B lymphocytes all start out producing IgM Abs. Upon encountering Ag, the cells become activated and make a switch from IgM to other Ig classes. This class switch serves to distribute a particular V region to different Ig C regions. Each C region mediates a specialized effector function, and so, through switching, an organism can guide its Abs to various sites. Creating the new H c...

• Vol 9 • May 2007 406 Ataxia-telangiectasia is a rare autosomal recessive multisystem disorder characterized by progressive cerebellar ataxia, oculocutaneous telangiectasia, recurrent sinopulmonary infection – all due to immune defects, and a high incidence of mainly B lymphoid malignancy [1]. Ataxiatelangiectasia results from mutations in a single gene, ataxia telangiectasia mutated (ATM). Th...

We have developed an efficient in vitro class switching system using a subclone (CH12F3) of the IgM+ CH12.LX lymphoma cell line. CH12F3 cells switched from surface IgM+ cells to surface IgA+ cells at a high frequency (50%) after 72 h stimulation with IL-4, transforming growth factor (TGF)-beta and CD40L. No other class isotype-producing cells were detected, indicating that the CH12F3 clone is e...

Mehmet Halil Celiksoy1, Stephan Borte2, Aydan İkincioğulları3, Meltem Ceyhan Bilgici4, Filiz Karagöz5, Ayhan Gazi Kalaycı6, Alişan Yıldıran3 1Ondokuz Mayıs University Faculty of Medicine, Department of Pediatric Allergy and Immunology, Samsun, Turkey 2Leipzig University Faculty of Medicine, Department of Clinical Immunolgy, Leipzig, Germany 3Ankara University Faculty of Medicine, Department of ...