The present invention encompasses PRLR binding proteins. Specifically, the invention relates to antibodies that are chimeric, CDR grafted and humanized antibodies. Preferred antibodies have high affinity for hPRLR and neutralize hPRLR activity in vitro and in vivo. An antibody of the invention can be a full-length antibody or an antigen-binding portion thereof. Methods of making and methods of using the antibodies of the invention are also provided. The antibodies, or antibody portions, of the invention are useful for detecting hPRLR and for inhibiting hPRLR activity, e.g., in a human subject suffering from a disorder in which hPRLR activity is detrimental. Also included in the invention are anti-PRLR antibody drug conjugates (ADCs).本發明包含PRLR結合蛋白質。特定言之,本發明係關於抗體,該等抗體為嵌合、CDR移植及人類化抗體。較佳抗體對hPRLR具有高親和力且在活體外及活體內中和hPRLR活性。本發明之抗體可為全長抗體或其抗原結合部分。亦提供本發明抗體之製造方法及使用方法。本發明之抗體或抗體部分適用於偵測hPRLR及例如在罹患其中hPRLR活性有害之病症的人類個體中抑制hPRLR活性。本發明亦包括抗-PRLR抗體藥物結合物(ADC)。