Intracellular multiplication of Legionella pneumophila in HL-60 cells functionally differentiated in response to 22-oxacalcitriol.
The agent 1,25-dihydroxyvitamin D3 (D3) induces the differentiation of HL-60 human leukemia cells into functional monocyte-like cells that can support the intracellular multiplication of Legionella pneumophila. 22-Oxacalcitriol (OCT), a synthetic analogue of D3, exhibits greater differentiation-inducing activity than D3 in WEHI-3 mouse leukemia cells and has been suggested to be clinically more useful because of its lower hypercalcemic activity. The abilities of OCT and D3 to induce the functional differentiation of human leukemia HL-60 cells have now been investigated. OCT induced the differentiation of HL-60 cells into monocyte-like cells to a similar extent as D3. Thus, both OCT and D3 increased (1) the surface expression of CD11b, CD11c, CD14, and CD35; (2) nonspecific esterase staining; and (3) phagocytic activity toward fluorescent beads. HL-60 cells differentiated in response to OCT also supported the intracellular multiplication of L. pneumophila. Activation of both OCT- and D3-treated HL-60 cells with human recombinant interferon-gamma (IFN-gamma) for 24 h before infection markedly inhibited L. pneumophila multiplication. IFN-gamma activation enhanced superoxide anion generation by D3-treated HL-60 cells but not by OCT-treated HL-60 cells, suggesting that the inhibition of L. pneumophila multiplication in IFN-gamma-activated cells is independent of superoxide generation. Finally, D3, but not OCT, markedly stimulated the formation of osteoclast-like multinucleated cells from mouse bone marrow cells, consistent with the lower hypercalcemic activity of OCT.
Matsuzaki
M
M
Department of Internal Medicine, Saga Medical School, Japan.
Shimamoto
Y
Y
Watanabe
M
M
Kukita
A
A
Yoshida
S
S
Tadano
J
J
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001853:Bone Marrow / Q000187:drug effects; D001854:Bone Marrow Cells; D002117:Calcitriol / Q000031:analogs & derivatives* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D007424:Intracellular Fluid / Q000382:microbiology; D016952:Legionella pneumophila / Q000254:growth & development*; D007951:Leukemia, Myeloid / Q000188:drug therapy* / Q000382:microbiology* / Q000473:pathology; D051379:Mice; D009000:Monocytes / Q000166:cytology / Q000187:drug effects; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects / Q000648:ultrastructure; D011994:Recombinant Proteins; D013481:Superoxides / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects
D000970:Antineoplastic Agents; D011994:Recombinant Proteins; D013481:Superoxides; D007371:Interferon-gamma; D002117:Calcitriol; C051883:maxacalcitol