The role of IL-2 interaction with p75 and p55 receptor molecules in the stimulation of cell proliferation.
This report addresses the role of individual IL-2 binding proteins of the IL-2 receptor in the stimulation of cell proliferation by IL-2. Murine IL-3-dependent cell lines were established which expressed the human p75 IL-2-binding protein, in the absence or presence of the human p55 IL-2-binding protein. Whereas p75 expression was sufficient to confer response to an intermediate (half-maximal stimulation at 100 pM) concentration of IL-2, additional expression of p55 increased the sensitivity of the cells to half-maximal stimulation at 10 pM IL-2. A mutant IL-2 molecule, Lys-20 IL-2 which is known to be defective of p75 interaction, was unable to stimulate cells expressing only p75: p55 co-expression could restore its activity. Under conditions of low p75 expression, Lys-20 IL-2 could act as an antagonist of wild-type IL-2 action. These data support a role for p55 in the enhancement of responsiveness to IL-2.
Perkins
G R
GR
Chester Beatty Laboratories, Institute of Cancer Research, London, UK.
Flemming
C L
CL
Kabat
D
D
Collins
M K
MK
D000818:Animals; D001667:Binding, Competitive; D002460:Cell Line; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008970:Molecular Weight; D009154:Mutation; D015375:Receptors, Interleukin-2 / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins