抗CD4抗体不同地调节CD4，45RO~＋和CD4，45RA~＋T细胞的辅助性功能及TCR／CD3调节的Ca￣（2＋）信号

ANTI-CD4 ANTIBODIES DIFFERENTIALLY REGULATES THEHELPER FUNCTION OF CD4 , 45RA￣+VERSUS CD4, 45RO￣+TCELLSAND T CELL RECEPTOR-MEDIATED Ca￣(2+) SIGNALS

观察了抗ＣＤ４抗体（ａｎｔｉ－ＣＤ４）在体外对ＣＤ４Ｔ淋巴细胞亚群ＣＤ４，４５ＲＡ￣＋和ＣＤ４，４５ＲＯ￣＋Ｔ细胞的辅助性功能及Ｔ细胞受体调节的细胞内Ｃａ￣（２＋）信号的影响。ａｎｔｉ－ＣＤ４主要是通过影响Ｔ－Ｂ淋巴细胞相互作用早期而影响ＣＤ４，４５ＲＯ￣＋Ｔ细胞的辅助性功能；ａｎｔｉ－ＣＤ４对ＴＣＲ／ＣＤ３调节的Ｔ细胞增殖反应的抑制是由于抑制了细胞内Ｃａ￣（２＋）信号的传导，并且与ＣＤ４５的分子结构密切相关。

n this study , only CD4 , 45RO￣+ but not CD4 , 45RA￣+T cells were able to promote B cell dif-ferentiation and proliferation which could be inhibited by anti-CD4. However . neither IL-Z norIL-4 was dramatically influenced by anti-CD4 in CD4, 45RO￣+T cells. When we investigated theability of anti-CD4 to inhibite conjugate formation between T and B cells,we found that CD4,45RO￣+T cells formed more TB cell conjugates than CD4 . 45RA￣+T cells and only the conjugateformation by CD4 ,45RO￣+T cells was inhibited by anti-CD4. Anti-CD4 inhibited not only anti-CD3 (solid phase)induced proliferative response but also anti-CD3 mediated Ca￣(2+) sigmal in CD4 ,45RO￣+T cells. However. influx of extracellular calcium as mediated by a calcium-ionophore(ion-omycin)could overcome the inhibitory effect of anti-CD4 and completely restored the prolifera-tion response of CD4, 45RO￣+T cells. These results suggest that anti-CD4 inhibits helper functionof CD4, 45RO￣+ T cells at an early phase of T-B interaction and CD4, 45RO￣+T cells are moresusceptible to anti-CD4 inhibition on their proliferative response than CD4, 45RA￣+T cells corre-sponding with and probably depending on reduction of[Ca￣(2+)]i in CD4, 45RO￣+T cells.