Amplification of human B cell activation by a monoclonal antibody to the B cell-specific antigen CD22, Bp 130/140.
Amplification of human B cell activation by a monoclonal antibody to the B cell-specific antigen CD22, Bp 130/140.
复制标题
B 细胞特异性抗原 CD22 (Bp 130/140) 的单克隆抗体可放大人 B 细胞的活化。
作者：
A. Pezzutto;B. Dörken;G. Moldenhauer;E. Clark
B细胞特异性抗原CD 22是130/140-Kd复合物，并且在人B细胞抗原中是独特的，因为其表面表达限于IG+ B细胞的亚群。在此，通过使用针对分子上的一个表位的mAb HD 6来评价CD 22抗原的功能。HD 6抗体与抗Ig共刺激诱导小而致密的扁桃体细胞增殖;然而，抗体本身缺乏刺激活性。抗CD 22抗体也能诱导更多的抗Ig处理的B细胞脱离G 0期进入G1期。它也是低分子量的共刺激。BCGF和针对50-Kd多肽Bp 50的抗体，所述多肽Bp 50介导BCGF样活性。不同B细胞组分的动力学实验和分析结果表明，抗CD 22在B细胞活化的早期阶段起作用，可能是通过放大抗Ig信号。抗-CD 22 HD 6的F（ab '）2片段在诱导B细胞增殖增强方面与完整抗体一样有效，表明该分子的Fc部分不是活性所必需的。这些实验的结果，连同Bp 130/140抗原在B细胞个体发育中的有趣分布，表明该分子在导致B细胞活化和增殖的过程中起重要作用。
The B cell-specific antigen CD22 is a 130/140-Kd complex and is unique among human B cell antigens, since its surface expression is restricted to a subpopulation of Ig+ B cells. Here the function of the CD22 antigen was evaluated by using the mAb HD6, directed against one of the epitopes on the molecule. The HD6 antibody was constimulatory with anti-Ig in inducing small, dense tonsillar cells to proliferate; however, the antibody by itself was devoid of stimulatory activity. Anti-CD22 antibody also induced more anti-Ig-treated B cells to leave G0 and enter the G1 phase of the cell cycle. It also was constimulatory with low-m.w. BCGF and with an antibody to a 50-Kd polypeptide, Bp50, which mediates a BCGF-like activity. Results of kinetic experiments and analysis of different B cell fractions suggested that anti-CD22 acts during an early phase of B cell activation, probably by amplifying the anti-Ig signal. F(ab')2 fragments of anti-CD22 HD6 were as effective as the whole antibody in inducing augmentation of B cell proliferation, showing that the Fc portion of the molecule was not required for the activity. The results of these experiments, together with the intriguing distribution of the Bp 130/140 antigen in B cell ontogeny, suggest that this molecule plays an important role in the process that leads to B cell activation and proliferation.