Open AccessCross-linking of interleukin 4 to surface molecules on murine T and B lymphocytes.
Author(s) -
Rafael FernandezBotran,
Jonathan W. Uhr,
Ellen S. Vitetta
Publication year - 1989
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.86.11.4235
Subject(s) - lymphokine , receptor , interleukin 2 , population , cell surface receptor , interleukin 4 , monoclonal antibody , cell , biology , chemistry , interleukin , biochemistry , cytokine , antibody , microbiology and biotechnology , in vitro , immunology , demography , sociology
Interleukin 4 (IL-4) is a T-cell derived lymphokine with multiple activities on a variety of cells. An intriguing feature of the different IL-4-mediated activities is their requirements for markedly different concentrations of IL-4 even on the same cell population. To gain some insight into the phenomenon, we have analyzed the structure of IL-4-binding proteins on T and B cells by cross-linking different concentrations of 125I-labeled IL-4 (125I-IL-4) to cells. Cross-linking of 125I-IL-4 at relatively low concentrations in the presence of the cross-linking agent 3,3'-dithiobis(propionic acid hydroxysuccinimide ester) resulted in the detection of the previously described 60- to 75-kDa protein. At higher 125I-IL-4 concentrations, however, an additional molecule of 105 kDa was observed. Cross-linking of 125I-IL-4 to both molecules was specific; it was inhibited by the presence of a 50-fold excess of either unlabeled IL-4 or monoclonal anti-IL-4 antibody. Furthermore, considerable size heterogeneity of the IL-4-binding proteins was evident in different cell populations. These results suggest that IL-4 receptors might have a more complex structure than originally reported and/or that high concentrations of IL-4 might induce interactions of the previously described IL-4 receptor (60-75 kDa) with a 105-kDa molecule. Hence, it is possible that IL-4 might generate a different signal at high concentrations through interaction of its receptor with another membrane molecule.