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

淋巴因子激活杀伤（LAK）细胞疗法在美国国立卫生研究院的rosenberg博士首次应用后，已被应用于临床但要使LAK细胞疗法成为临床常规的肿瘤治疗手段，还需进一步提高其临床疗效。我们在LAK细胞上发现了膜淋巴毒素（mLT）的表达，并建立了一种分离mLT表达的LAK细胞的方法。缺乏mLT表达的LAK细胞（mLT阴性LAK细胞）具有CD3、CD4、CD8等多种表面抗原的表面表达，保持了LAK细胞NK、LAK活性等活性。另一方面，对HeLa细胞等多种肿瘤细胞具有较强的抗肿瘤活性。mLT阳性和阴性LAK细胞在细胞毒因子的产生和肿瘤杀伤功能上应该存在一定的差异。为了鉴定这些，我们制作了一个dna减法文库并进行了随机测序。克隆片段的同源性研究使我们能够发现与LAK细胞激活相关的新克隆。我们将三个新克隆（lake -1、lake -4和lake -5）的数据存入DDBJ数据库，并向其提交了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.