The present invention relates to antagonist antibodies that specifically bind to Notch 3 and inhibit its activation. The present invention includes antibodies binding to a conformational epitope comprising the first Lin 12 domain and the second dimerization domain. The present invention also includes uses of these antibodies to treat or prevent Notch 3 related diseases or disorders.本發明係關於特異結合至Notch 3且抑制其活化之拮抗劑抗體。本發明包括結合至一種包含第一Lin12域及第二二聚域之構形抗原決定基(epitope)之抗體。本發明亦包括該等抗體用於治療或預防Notch 3相關疾病或病症之用途。