The invention relates to antibodies directed against CD127 the alpha chain of the interleukin 7 (IL-7) receptor IL-7R) and which have antagonist properties for IL-7-IL-7R interaction may present cytotoxic activity against CD127 positive cells but do not increase the maturation of dendritic cells (DCs) induced by TSLP a cytokine also using CD127 as part of its receptor. Alternatively or in addition these antibodies do not induce the internalization of CD127 and/or inhibit the IL7 induced internalization of CD127. According to another aspect of the invention antibodies are provided which recognize a human CD127 epitope comprising sequences from the 2b site of CD127 in particular the epitope comprising comprises the human CD127 sequences of domain D1 and of the 2b site of CD127 in particular the epitope comprises at least one sequence from D1 comprising SEQ ID No: 115 (in particular comprising SEQ ID No: 10) and/or SEQ ID No: 111 and / or a sequence from the 2b site comprising the sequence of SEQ ID No: 116 and optionally also comprises SEQ ID No: 117 (in particular comprises SEQ ID No: 111).The antibodies of the invention are suitable for use inorder to remedy to a condition diagnosed in a human patient which results from pathogenesis related to lymphopoiesis when IL 7 signalling pathways provide contribution to said pathogenesis especially when an increase in the maturation more precisely the upregulation of costimulatory molecules of dendritic cells is undesirable.
