BAY 50-4798, a novel, high-affinity receptor-specific recombinant interleukin-2 analog, induces dose-dependent increases in CD25 expression and proliferation among unstimulated, human peripheral blood mononuclear cells in vitro

Clin Immunol. 2004 Dec;113(3):248-55. doi: 10.1016/j.clim.2004.07.009.


Interleukin-2 administration induces CD4 T cell expansion in HIV-infected patients, however, toxicity can limit dosing. BAY 50-4798 is a recombinant IL-2 analog with >1000-fold specificity for the high-affinity IL-2 receptor. The effects of this compound on unstimulated human PBMC were evaluated. PBMC from HIV(-) and HIV(+) donors were cultured in vitro with incremental doses of BAY 50-4798 or aldesleukin. CD25 expression and proliferation were evaluated with flow cytometry. Cytokine levels were measured by ELISA in culture supernatants. BAY 50-4798 induced dose-dependent increases in CD25 expression and proliferation of T cells, NK, and B cells and showed selectivity for CD4 T cells expressing CD25. Induction of pro-inflammatory cytokines was also dose-dependent and was observed at the concentrations of BAY 50-4798 with the highest biologic activity. These data suggest that BAY 50-4798 can induce proliferation of unstimulated T cells but loss of T cell selectivity and induction of pro-inflammatory cytokines occur at concentrations exerting the highest biologic activity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • B-Lymphocytes / cytology
  • B-Lymphocytes / drug effects
  • B-Lymphocytes / immunology
  • B-Lymphocytes / metabolism
  • Cell Proliferation / drug effects
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • HIV Infections / immunology
  • HIV Infections / pathology
  • Humans
  • Inflammation / immunology
  • Interleukin-2 / analogs & derivatives*
  • Interleukin-2 / pharmacology*
  • Ki-67 Antigen / metabolism
  • Killer Cells, Natural / cytology
  • Killer Cells, Natural / drug effects
  • Killer Cells, Natural / immunology
  • Killer Cells, Natural / metabolism
  • Leukocytes, Mononuclear / cytology*
  • Leukocytes, Mononuclear / drug effects
  • Leukocytes, Mononuclear / metabolism*
  • Leukocytes, Mononuclear / virology
  • Receptors, Interleukin-2 / metabolism*
  • Recombinant Proteins / pharmacology*
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / virology
  • Up-Regulation / drug effects


  • Interleukin-2
  • Ki-67 Antigen
  • Receptors, Interleukin-2
  • Recombinant Proteins
  • aldesleukin