近年來，許多研究報告指出CD8+ T細胞可依其分泌之細胞激素 ( cytokine ) 類型而分群 : 第一型T細胞又稱Tc1 T細胞主要分泌IL-2，IFN-和TNF- ; 及第二型T細胞又稱Tc2 T細胞主要分泌IL-4，IL-5和IL-10。而在初次活化培養時外加IL-4可迫使T細胞往第二型T細胞方向發展。
在活體中，已分化至第一型或第二型之CD4+和CD8+ T細胞其分化狀態之持續已有文獻報導。文獻中指出不論是在CD4+或CD8+ T細胞中，第一型和第二型T細胞在活體中存活期間不會改變其細胞激素分泌類型，亦即分化結果不可逆。
PMA和ionomycin皆為T細胞之活化原。綜合PMA，ionomycin及IL-4之作用可使從未被活化之CD8+ T細胞降低其細胞表面CD8分子之表現，往第二型T細胞之分化發展並且呈現有效的細胞毒殺能力。
此篇論文主要之目的是為了探討CD8+ T細胞在被PMA + ionomycin + IL-4於活體外活化後，其功能上之特性及其特性之穩定度。在此特別討論三功能特性之穩定性及可逆性 : IL-4分泌能力，CD8分子表現之失去及細胞毒殺能力。
結果中指出，被PMA + ionomycin + IL-4於活體外活化後，B10 T細胞可維持IL-4分泌能力，但2C轉殖基因T細胞無法維持其IL-4 分泌能力。B10及2C轉殖基因T細胞於失去細胞表面CD8分子表現後，不會再度回復其表現，則此為不可逆現象。被活化之B10 T細胞具有良好的細胞毒殺能力，且此能力於活體中可被維持下去。

According to distinct cytokine secreting profile, CD8+ T cells can be defined as two populations : type 1 or Tc1 T cells that secret IL-2, IFN- and TNF- ; type 2 or Tc2 T cells that secret IL-4, IL-5 and IL-10. The presence of IL-4 in primary activation culture will drive CD8+ T cells to differentiate into Tc2 phenotype.
In vivo persistence of type 1 and type 2 polarization have been documented in CD4+ and CD8+ T cells. The reports demonstrated that both in CD4+ and CD8+ T cells, neither type 1 or type 2 T cells would change their cytokine secreting profile after surviving in vivo.
PMA and ionomycin are mitogens for T cells. The combine actions of PMA + ionomycin + IL-4 can induce naive CD8+ T cells to down-regulate surface CD8 expression, undergo Tc2 differentiation and express efficient cytotoxic activity.
The main purpose of this study is to identify the functional fate of naive CD8+ T cells activated in vitro by PMA + ionomycin + IL-4. Specifically, stability and potential reversibility with respect to IL-4 producing ability, loss of CD8 expression and ctyotoxic activity were examined.
The results indicated that conferred IL-4 producing ability of B10 T cells can persist in vivo but 2C tg T cells can not retain this functional characteristic. Down-regulation of CD8 expression is irreversible both in B10 and 2C tg T cells. Activated B10 T cells are potent cytotoxic effectors, and their potentials of regaining cytotoxic activity can exist in vivo.

Abbreviation...................................................I
English Abstract.............................................III
中文摘要.......................................................V
Introduction...................................................1
Material and Method............................................6
Mice.........................................................6
Solution.....................................................6
Panning Plate................................................7
Staining and Sorting.........................................8
Purification of B10 / 2C naive CD8+ T cells .................9
Generation of P + I + IL-4 activation B10 / 2C T cells......10
Generation of B10 / 2C CD8- memory T cells..................11
Functional Assay............................................13
Preparation of B10 / B10A B cell blasts for stimulation...13
IL-2 / IL-4 Bioassay......................................15
IFN-gamma ELISA...........................................16
IL-4 Producing Ability....................................18
CD8 Expression............................................18
Cytotoxicity Activity.....................................19
Results.......................................................22
Discussion....................................................28
Figures.......................................................33
Reference.....................................................42

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