Identification of LAK-cell activation related gene using a substraction method.

LAK细胞疗法在美国NIH的Rosenberg博士首次应用后已进入临床，但要使其成为临床上常规的肿瘤治疗手段，其临床效果还有待进一步提高。我们发现LAK细胞上有膜光敏素（mLT）的表达，并建立了一种使特异性LAK细胞去mLT表达的方法。缺乏mLT表达的LAK细胞（mLT阴性LAK细胞）具有多种表面抗原如CD 3、CD 4和CD 8的表面表达，并保持LAK细胞的NK和LAK活性。另一方面，它对许多肿瘤细胞如HeLa细胞的抗肿瘤活性减弱。mLT阳性与阴性LAK细胞在产生细胞毒因子和杀伤肿瘤功能上可能存在一定差异。为了鉴定这些，我们制作了cDNA消减文库并进行随机测序。克隆片段的同源性分析使我们能够找到与LAK细胞活化相关的新克隆。我们将3个新克隆（LAK-1、LAK-4和LAK-5）的数据存入DDBJ数据库，并向DDBJ数据库提交了EST数据。

Lymphokine-activated killer (LAK) cell therapy has been applied clinically after the initial application carried by Dr.Rosenberg, NIH,U.S.A.However, the LAK cell therapy should be greatly improved of its clinical effects in order to be routine clinical cancer therapy. We discovered the expression of membrane lymphotoxin (mLT) on the LAK cells and established a method to make special LAK cells devoiding mLT expression. The LAK cells lacking mLT expression (mLT negative LAK cells) posess the surface expressions of many surface antigens such as CD3, CD4 and CD8, keep the LAK cell activities such as NK and LAK activities. On the other hand, it loose anti-tumor activities against many tumor cells such as HeLa cells. There should be some differences in the production cytotoxic factors and tumoricidic functions between mLT positive and negative LAK cells. To identify these, we made a cDNA-subtraction library and carried out ramdom sequencing. Homology investigation of cloned fragments enabled us to find out new clones that will be assocated with LAK cell activation. We deposited data of three new clones (LAK-1, LAK-4 and LAK-5) to the DDBJ data bank and also submitted a EST data to it.