An isolated antibody, comprising: heavy chain complementary determining regions CDR1, CDR2, and CDR3 of a heavy chain variable region sequence selected from SEQ ID NOs: 2, 6, 10, and 14; and light chain complementary determining regions CDR1, CDR2, and CDR3 of a light chain variable region sequence selected from SEQ ID NOs: 4, 8, 12, and 16; wherein the antibody binds specifically to a RSPO3 protein.一種分離的抗體,包含:重鏈可變區序列的重鏈互補決定區CDR1、CDR2和CDR3,該重鏈可變區序列係選自SEQ ID NOs:2、6、10和14;以及輕鏈可變區序列的輕鏈互補決定區CDR1、CDR2和CDR3,該輕鏈可變區序列係選自SEQ ID NOs:4、8、12和16;其中,該抗體與RSPO3蛋白特異性地結合。