FcγRIIB functions as an IgG transporter in the mammary gland - Xin Li; Lijuan Du; Zihui Wan; Zhiren Jin; Yuanhao Peng; Yongliang Fan; Cuncun Ke; Yonghe Ma; Haitang Han; Shuyang Yu; Gengsheng Cao; Tian Huang; et al. (Proceedings of the National Academy of Sciences, 2026)