Distinct roles of BCNP1 in B-cell development and activation

• Published in: International immunology 2020-01, Vol.32 (1), p.17-26
• Main Authors: Hong, Rongjian, Lai, Nannan, Xiong, Ermeng, Ouchida, Rika, Sun, Jiping, Zhou, Yang, Tang, Yue, Hikida, Masaki, Tsubata, Takeshi, Tagawa, Masatoshi, Wang, Yanqing, Wang, Ji-Yang
• Format: Article
• Language: English
• ISSN: 1460-2377; 1460-2377
• DOI: 10.1093/intimm/dxz055

BCNP1 regulates a wide variety of B cell functions Abstract B-cell novel protein 1 (BCNP1) has recently been identified as a new B-cell receptor (BCR) signaling molecule but its physiological function remains unknown. Here, we demonstrate that mice deficient in BCNP1 exhibit impaired B-cell maturation and a reduction of B-1a cells. BCNP1-deficient spleen B cells show enhanced survival, proliferation and Ca2+ influx in response to BCR cross-linking as compared with wild-type spleen B cells. Consistently, mutant B cells show elevated phosphorylation of SYK, B-cell linker protein (BLNK) and PLCγ2 upon BCR cross-linking. In vivo, BCNP1-deficient mice exhibit enhanced humoral immune responses to T-independent and T-dependent antigens. Moreover, aged mutant mice contain elevated levels of serum IgM and IgG3 antibodies and exhibit polyclonal and monoclonal B-cell expansion in lymphoid organs. These results reveal distinct roles for BCNP1 in B-cell development, activation and homeostasis.