Sj. Gibson et al., CELLULAR-REQUIREMENTS FOR CYTOKINE PRODUCTION IN RESPONSE TO THE IMMUNOMODULATORS IMIQUIMOD AND S-27609, Journal of interferon & cytokine research, 15(6), 1995, pp. 537-545
Imiquimod (R-837) and its analog, S-27609, belong to a class of imidaz
oquinolinamines that have potent antitumor and antiviral effects in an
imals, Much of their biologic activity is a result of the induction of
cytokines, including interferon-alpha (IFN-alpha), tumor necrosis fac
tor alpha (TNF), and others, In this study, the cells responsible for
S-27609- and imiquimod-induced cytokine production were characterized.
E rosette(+) T cells were not the major cell population responsible f
or IFN-alpha and TNF in response to S-27609 or imiquimod, In contrast,
E rosette(-) cells and unseparated PBMC produced similar concentratio
ns of IFN-alpha and TNF in response to S-27609 and imiquimod, Eliminat
ion of monocytes by treatment with the lysosomotropic agent L-leucine
methyl ester (LME) or depletion using antibody to CD14 and immunomagne
tic beads abrogated IFN-alpha and TNF production induced by S-27609, i
miquimod, or LPS but not poly(I)/(C). LME treatment also abolished int
erleukin (IL)-1 alpha, IL-beta, IL-6, and IL-8 production stimulated b
y S-27609 and imiquimod, Removal of HLA-DR(+) or CD36(+) monocytes als
o caused a significant reduction in S-27609- and imiquimod-induced IFN
-alpha and TNF, Elimination of B cells, NK cells, and dendritic cells
did not significantly reduce cytokine induction in response to S-27609
, Thus, the cell population responsible for the majority of cytokine r
elease in human PBMC in response to S-27609 and imiquimod is a E roset
te(-), CD14(+), CD36(+), HLA-DR(+) monocyte.