Monoclonal antibodies against the human interleukin-11 receptor alpha-chain (IL-11R alpha) and their use in studies of human mononuclear cells

A panel of 14 hybridoma cell lines secreting monoclonal antibodies against the human interleukin-11 receptor alpha chain (hIL-11R alpha) was obtained using two different approaches. Two antibodies were raised against peptides of the N- and C-terminal sequences, respectively, of the extracellular par t of the hIL-11R alpha. Another group of 12 antibodies was generated agains t a hybrid protein consisting of the extracellular part of the hIL-11R alph a fused to mature full-length human IL-2. All these antibodies recognized n ative hIL-11R alpha and most also recognized the denatured receptor on immu noblots after SDS-PAGE. Four different epitopes were identified on the extr acellular part of the hIL-11R alpha. One epitope, defined by the E27 antibo dy, is located at the N-terminus and the other three epitopes are clustered in the membrane-proximal, C-terminal region. The antibodies defining epito pes I and II recognized membrane-bound hIL-11R alpha expressed in gp130/hIL -11R alpha-cotransfected Ba/F3 cells. The E27 antibody cross-reacted with m urine IL-11R alpha, in agreement with the fact that the N-terminal region i s highly conserved between species. The other 13 antibodies all recognized a region between amino acids 319 and 363, which is the membrane-proximal pa rt of the hIL-11R alpha. This region, which is less conserved between mouse and human, is shown here to be an immunodominant region. Anti-IL-11R alpha monoclonal antibodies, which have not been described previously enabled us to explore the expression and tissue distribution of IL-11R alpha on human peripheral blood mononuclear cells and cell lines. The antibodies provide powerful tools for the study of the regulation and function of the receptor . (C) 2000 Elsevier Science B.V. All rights reserved.