| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1999: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
We immunized mice with intact cells of neuroblastoma GOTO cells and melanoma G361 cells and obtained two interesting monoclonal antibodies(mAbs), mAb I-13 and mAb AG23, which respectively recognized cell surface antigens. I tried to identify the antigens for two mAbs, and I investigated the differentiation of GOTO cells using these mAbs.
By fluorescence-activated cell sorter(FACS)analysis of various cells, the mAb I-13 recognized neuroblastoma cells GOTO and IMR-32 very well, but did not recognize other cells tested. On the other hand, the mAb AG23 recognized all cells tested except GOTO.It turned out that the antigen for mAb I-13 was a sphingolipid and that for AG23 was a glycoprotein, CD44.
5-Bromo-2' -deoxyuridine(BrdU)-treated GOTo cells, which are differentiated int Schwann cells, expressed CD44 on the cell surface. The CD44 species expressed was the hemopoietic form(CD44H)encoding long cytoplasmic tail. GOTO cells differentiated into neural cells by serum depletion did not express CD44. On the other hand, GOTO cells became a little less responsive with the mAb I-13 after the differentiation into Schwann as well as neural cells.
The antigen lipid was found exclusively in membrane microdomain, called lipid rafts. CD44 in BrdU-treated GOTO cells also partitioned itself into lipid rafts, although it was found in both plasma membrane fractions and lipid rafts fractions in the case of melanoma G361 cells. I think that CD44 in BrdU-treated GOTO cells might play an important role in cells differentiated into Schwann cells.
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