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Both the pre‐BCR and the IL‐7Rα are essential for expansion at the pre‐BII cell stage in vivo
Author(s) -
Erlandsson Lena,
Licence Steve,
Gaspal Fabrina,
Lane Peter,
Corcoran Anne E.,
Mårtensson IngaLill
Publication year - 2005
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.200425821
Subject(s) - biology , in vivo , microbiology and biotechnology , genetics
Abstract During B cell development, proliferative expansion takes place after expression of the pre‐BCR. At this pre‐BII cell stage, the IL‐7Rα is also expressed. Some in vitro studies suggest that pre‐BCR‐dependent expansion relies on the IL‐7Rα, and others that it does not. It has also been suggested that the pre‐BCR mediates down‐regulation of the IL‐7Rα. However, the in vivo relationship between the pre‐BCR and the IL‐7Rα has not been previously examined. Here, we have investigated this by establishing mice lacking both receptors. Our results show that in the absence of the IL‐7Rα, the pre‐BII population is reduced, as previously seen in mice lacking the pre‐BCR, demonstrating that the IL‐7Rα is important at this stage. A deficiency in both receptors results in a further reduction of the pre‐BII cell population. We conclude that both the IL‐7Rα and the pre‐BCR are required for optimal pre‐BII cell expansion. Furthermore, IL‐7Rα expression levels are normal in pre‐BCR‐deficient mice, suggesting that the pre‐BCR does not mediate its down‐regulation. As a consequence of the absence of both receptors, the peripheral B cell pool is severely depleted, resulting in atypical splenic B cell structures and reduced serum Ig levels.