| Summary: | 碩士 === 長庚醫學暨工程學院 === 基礎醫學研究所 === 85 === MCS2A 是注射人類軟組織黑色素瘤細胞株 (MST-2) 至裸鼠腹腔後產
生腹水 (ascites),在試管中所培養出的細胞株. 由於此細胞株的形態及
特性均和人類軟組織黑色素瘤細胞株(MST-2) 不同, 因此利用染色體分析
才發現: MCS2A 原來是被誘發出的一種小鼠惡性腫瘤細 胞. 依據細胞生
長的特性, MCS2A 可被區分為二大族群, 一為飄浮的細胞, 一為貼壁的細
胞. 以不同之單株抗體及免疫螢光反應/細胞流體力學分析後發現此群飄
浮的惡性細胞是為小鼠惡性 B 淋巴細胞 (表現 CD40 與 k-輕鏈). 免疫
化學染色結果, 可看到 MCS2A 細胞表現出巨噬細胞與顆粒性細胞的特性,
推斷小鼠 B 細胞可能和骨髓細胞 (myeloid cells) 具有相同來源
(common lineage). MCS2A 之另一項令人感到驚奇的是其表面具有和抗人
類主要組織複合體抗原第一型抗 HLA-ABC 之單株抗體 (W6/32) 有強烈的
反應, 但這並不意味 著 MCS2A 細胞有 HLA-ABC 分子的表現, 因為五種
和 W6/32 具有不同抗 HLA-ABC 抗原決定位的單株抗體和一種抗B2-微球
蛋白之單株抗體均不與 MCS2A 細胞作用. 以免疫螢光染色/ 細胞流體力
學分析配合限制性吸釋 (limiting dilution) 的方法, 分出一系列的單
株細胞亞群 (clonal sublines), 發現飄浮的細胞群中可以大致分出大的
細胞亞群及小的細胞亞群. 而飄浮的大細胞與大部份的貼壁細胞可表現出
W6/32 認知的抗原決定位, 以西方點墨分析, 到目前為止我們尚未能確定
MCS2A 細胞上被 W6/32 認知的分子. 另外, 貼壁的細胞表現出許多不同
的細胞特性, 包括: 纖維母細胞及類表皮細胞. 同時, 我們也發現貼壁
的細胞會分泌 GM-CSF 生長因子, 但是飄浮的細胞中沒有認何亞群會分泌
此生長因子. 綜合上述之結果, 此 MCS2A 惡性細胞株的特性顯示出它含
有多種不同之亞細胞群, 可以提供我們一有價值的材料來更進一步評估小
鼠 B 細胞成長與分化, 包括 B 細胞的發生路徑(ontology), 並且提供研
究人類血癌之生長分化與使用抗體 (例如: HLA-ABC) 治療之動物模式.
This study was designed to characterize a mouse cell line, MCS2
A, which was established from ascites of a nude mouse after i.p.
injection with cells of the human soft tissue melanoma cell
line, MST-2. Chromosome analysisi showed that all MCS2A cells
were of mouse origin. MCS2A cells could be grossly categorized
into 3 populations based on their in vitro growth patterns:
plastic-adherent (H2Dd+/-, W6/32+, k-, CD40-), small-sized
nonadherent (H2Dd-, W6/32-, k+, CD40+, CD5+) and large-sized
nonadherent (H2D+, W6/32+, k-, CD40+, CD5+). Theexpression of
CD40, CD45 and k-light chain on the surface of MCS2A nonadherent
cells suggested their B lymphoid nature. Interestingly, these
cells also expressed monocyte/macrophage (MOMA-2) and
granulocyte (Ly-6G) markers, suggesting that mouse B cells and
myeloid cells may share the same common lineage, or
alternatively that there are biopotential precursors of both B
cellsand myeloid cells. Unexpectedly, we found that adherent
cells, and large-sized but not small-sized nonadherent cells of
MCS2A reacted strongly with amonoclonal antibody (MAb W6/32)
against a monomorphic determinant of humanMHC class I molecules.
However, MCS2A cells did not react with 5 other anti-HLA-ABC
MAbs to different epitopes, nor with MAb to B2-microglobulin
antibody. To characterize MCS2A cells further, analysis of 37
clonal sublines confirmed what had been observed with MCS2A
cells of mass cultures. Interestingly, both small-sized and
large-sized cells were present in eachof 11 nonadherent sublines
established. So far, attempts made to define the molecular
nature of the antigen on MCS2A recognized by W6/32 antibody
usingimmunobloitting were not successful.The sublines of
adherent cells appeared to be mostly fibroblast-like and a few
epitheloid cells, and were able to secret granulocyte-macrophage
colony stimulating factor (GM-CSF), which was notdetectable in
any of the subclones of nonadherent cells by GM-CSF-dependent
cellgrowth assays. The surface molecule bearing the W6/32
epitope could be a new early B cell marker or a new tumor-
associated antigen, which deserves furtherinvestigation.
Induction of B cell differentiation may help understand the
relationships between the 2 nonadherent cell types. MCS2A cells
should providevaluable materials for (i) the study of murine B
cell ontology, and (ii)animal models in studies of
leukemogenesis, regulation of leukemia cell growth,and
differentiation, and therapeutic strategies using MAbs, such as
W6/32.
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