Analysis of poly(D,L-lactic-co-glycolic acid) nanosphere uptake by human dendritic cells and macrophages in vitro.
OBJECTIVE
The purpose of this study was to demonstrate and characterize phagocytosis of poly(D,L-lactic-co-glycolic acid) (PLGA) nanospheres by human dendritic cells (DCs).


METHODS
Parallel cultures of DCs and macrophages (Mphi) were established from peripheral blood leukocytes using media supplemented with granulocyte-macrophage colony stimulator factor and interleukin-4 (for DC) or granulocyte-macrophage colony stimulator factor alone (for Mphi). PLGA nanospheres containing tetramethylrhodamine-labeled dextran with or without an adjuvant, monophosphoryl lipid A, were prepared using a water/oil/water solvent evaporation technique. Cells were incubated with the nanospheres for 24 h. Confocal laser scanning microscopy was used to determine the intracellular location of the nanospheres and flow cytometry to measure the fraction of phagocytic cells in the culture and the amount of uptake per cell. After phagocytosis, cells were stained for MHC class II molecules, CD14, CD80, and CD86 to identify the phagocytic population.


RESULTS
DCs phagocytosed PLGA nanospheres as efficiently as Mphi. Cell-surface marker expression conclusively established that the phagocytic cells were DC.


CONCLUSIONS
DCs can take up PLGA nanospheres. Because DCs are the key professional antigen-presenting cells capable of stimulating naive T cells, our data suggest that PLGA nanospheres can be used as an efficient delivery system for vaccines designed to activate T cell-mediated immune responses.
Lutsiak
M E Christine
ME
Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.
Robinson
Deborah R
DR
Coester
Conrad
C
Kwon
Glen S
GS
Samuel
John
J
D002478:Cells, Cultured; D003713:Dendritic Cells / Q000378:metabolism*; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D008863:Microspheres; D036103:Nanotechnology / Q000379:methods*; D010587:Phagocytosis / Q000502:physiology; D011100:Polyglycolic Acid / Q000378:metabolism*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000378:metabolism*
D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid