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Biomedical subjects

Y Okayama

Publications and source records attributed to Y Okayama.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Further characterization of FcgammaRII and FcgammaRIII expression by cultured human mast cells.

BACKGROUND: We have reported that resting human mast cells exhibit minimal expression for FcgammaRI, and that interferon-gamma will upregulate this expression. The expression of FcgammaRII and FcgammaRIII by human mast cells remains to be fully examined. METHODS: To investigate FcgammaRII and FcgammaRIII expression, we determined mRNA and protein expression of FcgammaRII and FcgammaRIII in human peripheral blood CD34+ derived cultured mast cells by RT-PCR and flow cytometry. The expression of FcgammaRII and FcgammaRIII in intact and permeabilized mast cells was also compared. We measured histamine release to monitor mast cell degranulation following cross-linking of FcgammaRII. RESULTS: We found by RT-PCR that resting human mast cells exhibit mRNA for FcgammaRIIA, FcgammaRIIb1, FcgammaRIIb2 and FcgammaRIII but not FcgammaRIIC. FACS analysis of Fcgamma receptors in intact versus permeabilized mast cells showed expression of FcgammaRII to be 42.2 +/- 3.9% and this was unchanged by permeabilization. FcgammaRIII protein expression was minimal and this was also unchanged by permeabilization. Aggregation of FcgammaRII on human mast cells led to no significant degranulation as evidenced by histamine release. CONCLUSIONS: In addition to FcgammaRI expression, human mast cells express FcgammaRIIA, FcgammaRIIb1, FcgammaRIIb2 and FcgammaRIII mRNA, and significant surface expression of FcgammaRII. Aggregation of FcgammaRII on cultured human mast cells in this model was not followed by histamine release.

Cells, Cultured↗
PubMedDate not supplied

Multiple cytokine mRNA expression in human mast cells stimulated via Fc epsilon RI.

Cross-linkage of Fc epsilon RI on human lung mast cells purified by affinity magnetic selection with monoclonal antibody YB5.B8 against c-kit (purity > 90%) expressed mRNA for multiple cytokines. There was no constitutive expression of interleukin (IL)-4 mRNA. Mast cell stimulation with anti-IgE induced IL-4 mRNA expression which appeared maximal at 2 h and waned slowly over the next 24 h. IL-5, IL-6, IL-8 and tumour necrosis factor (TNF)-alpha mRNA were constitutively expressed. Mast cell activation with anti-IgE led to an increase of IL-5 and TNF-alpha mRNA signals within 2 h and which persisted for at least 24-48 h. On the other hand, IL-6 and IL-8 mRNA expression were not affected by anti-IgE challenge.

Antibodies, Anti-Idiotypic↗