Rat interleukin-2 immunoglobulin M fusion proteins are cytotoxic in vitro for cells expressing the IL-2 receptor and can abolish cell-mediated immunity in vivo

Transplantation. 1994 Oct 27;58(8):932-9. doi: 10.1097/00007890-199410270-00013.


A hybrid cDNA coding for a fusion protein between rat interleukin 2 (IL-2) and a truncated heavy chain from rat immunoglobulin M (IgM) was constructed. The rat IL-2 and rat IgM CH2-3-4 hybrid gene was subcloned into a vector (PKCR6) for expression of the fusion molecule in Chinese hamster ovary (CHO) cells. Cells transfected with the hybrid cDNA secrete multimeric forms of the fusion protein (IL-2-Mu). Size analysis of the construct revealed that the majority (95%) of the secreted proteins have a high mw (> 500 kDa). The IL-2-Mu construct bind specifically to cells bearing the IL-2 receptors (IL-2R) with a binding affinity around 5 nM. The specific binding to IL-2R leads to T cell proliferation or, if rabbit complement is added, to T cell lysis. Multimeric forms (> 500 kDa) of the fusion protein mediate complement-dependent lysis but trigger only weak proliferation when compared with the low-mw forms (< 500 kDa). In contrast, the latter only efficiently mediate T cell proliferation without inducing complement-dependent lysis. After intravenous administration of CHO supernatant containing IL-2-Mu, or purified IL-2-Mu proteins into rats, the fusion proteins disappeared from the circulation with a t1/2 of 1 hr. The circulating IL-2-Mu constructs in the rat serum retained their capacity to induce complement-dependent lysis of IL-2R-bearing T cells in vitro. Furthermore, the IL-2-Mu construct was able to suppress the delayed-type hypersensitivity (DTH) reaction (an IL-2R, T helper cell-dependent event) in mice. A weak immune response (antirat IL-2-Mu antibodies) was observed when rats received multiple daily injections of the construct.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibody Formation
  • Base Sequence
  • CHO Cells / chemistry
  • Cell Line / chemistry
  • Cricetinae
  • Cytotoxicity, Immunologic
  • Hypersensitivity, Delayed / prevention & control
  • Immunity, Cellular / immunology
  • Immunoglobulin M / chemistry
  • Interleukin-2 / immunology*
  • Mice
  • Molecular Sequence Data
  • Rats
  • Rats, Inbred BN
  • Receptors, Interleukin-2 / immunology*
  • Recombinant Fusion Proteins


  • Immunoglobulin M
  • Interleukin-2
  • Receptors, Interleukin-2
  • Recombinant Fusion Proteins