IL-6 attenuates apoptosis, while neither IL-6 nor IL-10 affect the numbers or protease phenotype of fetal liver-derived human mast cells.
BACKGROUND
The combination of recombinant human stem cell factor (rhSCF), rh interleukin (IL)-6 and rhIL-10 was reported to be optimal for mast cell development from cord blood progenitors and to induce chymase expression in all such mast cells earlier in their development than tryptase.


OBJECTIVE
The effects of rhIL-6 and rhIL-10 in various combinations on the rhSCF-dependent development of human mast cells from fetal liver progenitors were examined in serum-free media.


METHODS
Dispersed fetal liver cells were cultured in serum-free AIM-V medium with rhSCF alone, or with combinations of rhIL-6 and rhIL-10. Tryptase and chymase expression, surface Kit expression, metachromasia with toluidine blue and apoptosis were measured.


RESULTS
Neither rhIL-6 nor rhIL-10 nor the two interleukins together, when included from day 0 of culture, affected the number or protease phenotype of mast cells at 1 or 3 weeks. Expression of tryptase paralleled the appearance of metachromasia and surface Kit, both of which preceded chymase expression, regardless whether a rabbit polyclonal or mouse monoclonal anti-chymase antibody preparation was used. On the other hand, rhIL-6 markedly attenuated baseline levels of apoptosis in the presence of rhSCF as well as apoptosis occurring after withdrawal of rhSCF, whereas rhIL-10 had no effect.


CONCLUSIONS
RhIL-6 protected fetal liver-derived mast cells from apoptosis, particularly after withdrawal of rhSCF, but neither rhIL-6 nor rhIL-10 nor the combination of these interleukins affected the numbers or protease phenotype of these mast cells.
Kambe
M
M
Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298-0263, USA.
Kambe
N
N
Oskeritzian
C A
CA
Schechter
N
N
Schwartz
L B
LB
D017209:Apoptosis / Q000276:immunology*; D002452:Cell Count; D002478:Cells, Cultured; D053818:Chymases; D006801:Humans; D016130:Immunophenotyping; D016753:Interleukin-10 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D008099:Liver / Q000166:cytology / Q000201:enzymology* / Q000276:immunology*; D008407:Mast Cells / Q000201:enzymology* / Q000276:immunology*; D011994:Recombinant Proteins / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D019089:Stem Cell Factor / Q000494:pharmacology; D053802:Tryptases
D015850:Interleukin-6; D011994:Recombinant Proteins; D019089:Stem Cell Factor; C509190:Tpsb2 protein, mouse; D016753:Interleukin-10; D012697:Serine Endopeptidases; D053818:Chymases; C509222:Tpsab1 protein, mouse; D053802:Tryptases