Y. Mita et al., Toll-like receptor 2 and 4 surface expressions on human monocytes are modulated by interferon-gamma and macrophage colony-stimulating factor, IMMUNOL LET, 78(2), 2001, pp. 97-101
Human Toll-like receptor 2 (TLR2) and TLR4 are recently identified receptor
s. TLR4 was shown to be the main protein involved in recognizing Gram-negat
ive bacteria, whereas TLR2 is apparently the key factor in responses to oth
er types of microbial pathogens. We examined regulations of TLR2 and TLR4 s
urface expressions in human peripheral blood monocytes by interferon-gamma
(IFN-gamma) and macrophage colony-stimulating factor (M-CSF). IFN-gamma up-
regulated both TLR2 and TLR4, but enhanced the surface expression, on human
peripheral blood monocytes of TLR4 more than that of TLR2. On the other ha
nd, M-CSF up-regulated both TLR2 and TLR4 surface expression on human perip
heral blood monocytes, with no change in the ratio of TLR2/TLR4 surface exp
ression. These results indicate that IFN-gamma enhances receptors involved
in the response to Gram-negative bacteria more than those involved in respo
nses to other types of microbial pathogens, whereas M-CSF enhances the rece
ptor response to Gram-negative bacteria in the same manner as to other type
s of microbial pathogens. (C) 2001 Elsevier Science BN. All rights reserved
.