[PDF][PDF] Phagosome maturation proceeds independently of stimulation of toll-like receptors 2 and 4

RM Yates, DG Russell - Immunity, 2005 - cell.com
RM Yates, DG Russell
Immunity, 2005cell.com
Toll-like receptors modulate many aspects of the innate immune response. Recent reports
suggest that the maturation of phagosomes following particle uptake is modulated through
signaling of Toll-like receptors. In the current study, the kinetics of phagosome maturation
was evaluated quantitatively by ratio fluorometry to determine the lumenal pH of the
phagosomes and a FRET-based technique to determine the degree of
phagosome/lysosome fusion. Profiles generated for phagosomes containing experimental …
Summary
Toll-like receptors modulate many aspects of the innate immune response. Recent reports suggest that the maturation of phagosomes following particle uptake is modulated through signaling of Toll-like receptors. In the current study, the kinetics of phagosome maturation was evaluated quantitatively by ratio fluorometry to determine the lumenal pH of the phagosomes and a FRET-based technique to determine the degree of phagosome/lysosome fusion. Profiles generated for phagosomes containing experimental particles with or without the TLR ligands Pam3Cys-Ser-(Lys)4 or LPS failed to reveal a difference in maturation despite activating TLR-signaling pathways. Moreover, while macrophages defective in individual TLRs generated phagosome maturation profiles identical to wild-type macrophages, MyD88-deficient macrophages exhibited a marked depression in phagosome/lysosome fusion that appears independent of short-term TLR-mediated effects. The results demonstrate that the rate of maturation of phagosomes proceeds independently of TLR signaling pathways.
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