The immune response modifiers imiquimod and R-848 are potent activators of B lymphocytes

Cell Immunol. 2000 Jul 10;203(1):55-65. doi: 10.1006/cimm.2000.1673.


Imiquimod and R-848 are members of a family of immune response modifiers that stimulate cytokine production in monocyte/macrophages and dendritic cell cultures. This study evaluated the effects of the imidazoquinolines, imiquimod and R-848, on B lymphocyte activation. Both agents induced proliferation of murine T-cell-depleted and highly purified splenic B cell preparations as well as purified human B cells. Resting and activated B cells responded to these agents, with activated cells responding more efficiently. B cells from the LPS-hyporesponsive C3H/HeJ mice and guanosine-hyporesponsive SJL mice proliferated in response to imiquimod and R-848, indicating a different mechanism of action than lipopolysaccharide and guanine nucleosides. B cells were also stimulated by imiquimod and R-848 to produce increased immunoglobulin levels. Increased expression of a number of B cell activation markers were seen following imiquimod or R-848 stimulation. Finally, R-848 was shown to act as a vaccine adjuvant enhancing OVA-specific IgG2a levels while suppressing total IgE. These results indicate that R-848 and imiquimod are potent activators of B lymphocytes and are capable of augmenting antigen-specific immunoglobulin production.

MeSH terms

  • Adjuvants, Immunologic / pharmacology*
  • Aminoquinolines / pharmacology*
  • Animals
  • Antibody Specificity
  • Antigens, CD / immunology
  • B-Lymphocytes / drug effects
  • B-Lymphocytes / immunology*
  • B7-2 Antigen
  • Cells, Cultured
  • Guanosine / immunology
  • Humans
  • Imidazoles / pharmacology*
  • Imiquimod
  • Immunoglobulin Class Switching
  • Immunoglobulin E / biosynthesis
  • Immunoglobulin E / immunology
  • Immunoglobulin G / biosynthesis
  • Immunoglobulin G / immunology
  • Lipopolysaccharides / immunology
  • Lymphocyte Activation / drug effects*
  • Membrane Glycoproteins / immunology
  • Mice
  • Mice, Inbred Strains
  • Ovalbumin / immunology
  • Spleen / cytology
  • Spleen / immunology


  • Adjuvants, Immunologic
  • Aminoquinolines
  • Antigens, CD
  • B7-2 Antigen
  • CD86 protein, human
  • Cd86 protein, mouse
  • Imidazoles
  • Immunoglobulin G
  • Lipopolysaccharides
  • Membrane Glycoproteins
  • Guanosine
  • Immunoglobulin E
  • Ovalbumin
  • Imiquimod
  • resiquimod