A monoclonal mouse anti-human IL-2 receptor antibody (anti-Tac) will recognize molecules on the surface of Xenopus laevis immunocytes which specifically bind rIL-2 and are only slightly larger than the human Tac protein

Laurens N. Ruben, Lorene Langeberg, Arthur Malley, Richard H. Clothier, Carol Beadling, Rachel Lee, Stanley Shiigi

Research output: Contribution to journalArticle

2 Scopus citations


We have made visible the binding of a mouse monoclonal anti-human interleukin 2 (IL-2) receptor (anti-Tac) antibody on the surface of phytohemagglutinin (PHA)-stimulated Xenopusthymocytes using a colloidal gold-conjugated goat anti-mouse antibody and transmission electron microscopy. No binding was found when a different mouse monoclonal antibody (mAb) of the same isotype and subclass was tested, or when the anti-Tac antibody was omitted from the procedure. After metabolic radiolabeling of the IL-2 receptors with [35S]methionine using PHA-stimulated thymocytes of Xenopus laevis, the South African clawed toad, we show that a concentrated preparation of the mouse anti-human Tac antibody will immunoprecipitate a radiolabeled molecule just slightly larger than 55 kDa. Phorbol dibutyrate (PDB), an effective T cell mitogen, and cyclosporin A, an inhibitor of T cell mitogenesis in this species, are both capable of regulating the expression of this IL-2-binding molecule on Xenopus immunocytes [1]. Here, we use the calcium ionophore A23187 to show that the relationship between IL-2 receptor expression and mitogenesis, which was previously established in X. laevis [1], is associated with a calciumion flux. Flow cytometry is used for assaying alterations in epitope expression after binding the lectin-stimulated cells under test with a fluorescence (Fl*) conjugate of the anti-Tac antibody or a control mAb, which is either anti-DNP or anti-keyhole limpet hemocyanin (KLH) in specificity, but of the same mouse isotype and subclass as the anti-IL-2 receptor antibody.

Original languageEnglish (US)
Pages (from-to)117-125
Number of pages9
JournalImmunology Letters
Issue number2
Publication statusPublished - 1990
Externally publishedYes



  • Calcium ion flux
  • Cytokine
  • IL-2
  • IL-2 receptor
  • Molecular conservation

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy

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