Antibodies directed against the protein CD20, which is expressed by immune cells known as B cells, are used to treat B cell non-Hodgkin lymphoma and rheumatoid arthritis. Despite this, the function of CD20 has not been determined.
Now, a team of researchers led by Renι van Lier, at the Academic Medical Center, The Netherlands, has determined that CD20 has a nonredundant role in generating optimal B cell immune responses by analyzing a patient lacking the protein.
The research appears in the Journal of Clinical Investigation.
The patient was referred to the Academic Medical Center at four years of age, with a history of intermittent respiratory infections and recurrent bronchopneumonia. Detailed analysis of immune cells from the patient revealed that the B cells lacked CD20 expression due to a mutation in the CD20 gene. These CD20-deficient B cells failed to respond normally to certain stimuli in vitro, specifically those known as T-independent antigens. Further, vaccination of the patient with a T-independent antigen led to a markedly impaired B cell response.
The authors therefore conclude that CD20 has an important role in enabling B cells to respond optimally to T-independent antigens and that absence of this protein causes an immunodeficiency characterized by a reduced capacity to make B cell responses to T-independent antigens.
- Taco W. Kuijpers, Richard J. Bende, Paul A. Baars, Annette Grummels, Ingrid A.m. Derks, Koert M. Dolman, Tim Beaumont, Thomas F. Tedder, Carel J.m. Van Noesel, Eric Eldering and Renι A.w. Van Lier. CD20 deficiency in humans results in impaired T cell-independent antibody responses. Journal of Clinical Investigation, 2009; DOI: 10.1172/JCI40231
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