CD44分子在血细胞的表达及对T淋巴细胞增殖的影响

为了进一步探讨粘附分子CD44在血细胞的分布特点及与免疫功能的关系，利用荧光双染色一流式细胞仪技术检测各种血细胞的CD44分子的表达，利用^3H-TdR掺入法检测T细胞的DNA合成。结果显示：除血小板CD44分子的表达为阴性、胸腺细胞为弱阳性外，其他所有血细胞CD44分子的表达(包括红细胞、中性粒细胞、单核细胞、干细胞、T淋巴细胞、B淋巴细胞和NK细胞)均为阳性。单独抗CD3抗体可明显增强T细胞的DNA合成；但协同抗CD44抗体后，T细胞的DNA合成被明显抑制。单独抗CD44抗体对IL-2激活的T细胞DNA合成无明显影响；但协同抗CD2抗体后，可明显增强抗CD2抗体对IL-2激活的T细胞DNA合成的抑制。

Adhesion molecule CD44 expressions on blood cells and its effect on T lymphocyte proliferation

To further explore the characteristics of adhesion molecule CD44 distribution on various blood cells and the relationship between CD44 molecule and immune function,CD44 molecule expressions on various normal blood cells were assayed with the fluorescent double staining_FACS techniques and the effects of anti_CD44 antibody alone or anti_CD44 combined with anti_CD3 or anti_CD2 antibodies on the normal T lymphocyte proliferation were studied and the DNA synthesis in the T lymphocytes was determined with 3H_ TdR incorporation assay.The results showed that the CD44 molecule expression was positive in most blood cells including erythrocytes,neutrophils,monocytes(CD14+),stem cells (CD34+),T lymphocytes(CD3+),B lymphocytes( CD19+) and NK cells (CD16+/CD56+),but CD44 was negative in platelet and was dim positive in thymocyte (CD4+CD8+).Anti_CD3 antibody alone could increase t he DNA synthesis of T lymphocytes,but the combination of anti_CD3 with anti_CD44 antibodies could significantly inhibit the DNA synthesis of T lymphocytes.Anti_CD44 antibody alone had no influence on the DNA synthesis of T lymphocytes activated by IL_2,but when the combination of anti_CD44 with anti_CD2 antibodies could significantly increase the inhibitory effect of anti_CD2 antibody on the DNA synthesis of the IL_2 activated T lymphocytes.Therefore the CD44 molecule expressions on various blood cells further suggested that the CD44 molecule might widely mediate blood cell functions.Anti_CD3 antibody could up_regulate the CD44 molecule expression on T lymphocytes and the signaling induced by CD44 molecule could enhance T lymphocyte apoptosis.The inhibitory effects of T lymphocyte proliferation induced by the negative signal transduction resulted from the CD44_anti_CD44 cross_ligation might be associated with the cross_linkage with CD2 molecule.