A second human interleukin-2 binding protein that may be a component of high-affinity interleukin-2 receptors.

Journal Article

Although activated human T and B lymphocytes express both high-affinity and low-affinity membrane receptors for interleukin-2 (IL-2), the structural features that distinguish these receptors have remained unresolved. The high-affinity receptors appear to mediate IL-2 induced T cell growth and internalization of IL-2, whereas no function has yet been ascribed to the low-affinity receptors. The Tac antigen is an IL-2 binding protein of relative molecular mass 55,000 (Mr 55K) that participates in the formation of both high- and low-affinity receptors. But Tac complementary DNA transfection and membrane fusion studies have suggested that additional T-cell components are required to produce high-affinity IL-2 receptors. In this study, we report the identification of a second human IL-2 binding protein that (1) has an Mr of approximately 70K, (2) lacks reactivity with the anti-Tac antibody, (3) binds IL-2 with intermediate affinity and (4) is present on the surface of resting T cells, large granular lymphocytes (natural killer cells), and certain T and B cell lines in the absence of the Tac antigen. Chemical crosslinking of 125I-labelled IL-2 bound to high-affinity IL-2 receptors produces labelling of both the p70 protein and the Tac antigen and the anti-Tac antibody blocks the crosslink detection of both of these proteins. Expression of Tac cDNA in a T cell line expressing the p70 protein, but lacking both Tac and high-affinity receptors, results in the reconstitution of high-affinity IL-2 receptors in these cells. Together, these findings suggest that the high-affinity human IL-2 receptor may be a membrane complex composed of at least the p70 protein and Tac antigen.

Full Text

Duke Authors

Cited Authors

  • Dukovich, M; Wano, Y; Le thi Bich Thuy, ; Katz, P; Cullen, BR; Kehrl, JH; Greene, WC

Published Date

  • June 11, 1987

Published In

Volume / Issue

  • 327 / 6122

Start / End Page

  • 518 - 522

PubMed ID

  • 3108674

International Standard Serial Number (ISSN)

  • 0028-0836

Digital Object Identifier (DOI)

  • 10.1038/327518a0

Language

  • eng

Conference Location

  • England