[Apoptosis of human B cell lymphoma Raji cells induced by monovalent anti-CD20 antibody].
OBJECTIVE
The anti-CD20 antibodies and fragments have been applied for treatment of non-Hodgkin's lymphomas (NHL) in clinic. The new anti-CD20 antibodies and their fragments (unmodified or radiolabeled) yet have been exploited for those patients with incomplete response to rituximab. The chimeric antibody fragments Fab and F(ab) '(2) derived from HI(47)(a mouse anti-CD20 antibody) have been constructed. The present study was designed to determine the effect of HI(47) and chimeric anti-CD20 antibody fragments on growth inhibition and apoptosis of lymphoma cells.


METHODS
The binding of anti-CD20 antibodies to CD20 positive human B cell lymphoma Raji cells was examined using immunofluorescence assay. MTT method was used to evaluate the effect of chimeric antibody fragments on Raji cells growth. Annexin V staining and DNA ladder were used to examine the apoptosis of Raji cells induced by chimeric antibody fragments.


RESULTS
HI(47) and its chimeric antibody fragments were capable of binding to CD20 positive Raji cells with the binding rate of above 90%. HI(47) did not compete with rituximab in binding with Raji cells. The growth of Raji cells was inhibited by HI(47) and its fragments with the inhibition rates of (57+/-1.5)%, (65.2+/-2.5)%,and (77.2+/-3.2)%, respectively, at the concentration of 100 microg/ml. The monovalent antibody fragment Fab (20 microg/ml) induced the apoptosis of Raji cells with early apoptosis rate of 17%.


CONCLUSIONS
The chimeric anti-CD20 antibody fragments derived from HI(47) have inhibitory effect on Raji cells and can induce apoptosis of Raji cells.
Liu
Yin-Xing
YX
The National Laboratory of Experimental Hematology,Institute of Hematology,Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, PR China.
Fan
Dong-Mei
DM
Xiong
Dong-Sheng
DS
Xu
Yuan-Fu
YF
Shao
Xiao-Feng
XF
Xu
Yuan-Sheng
YS
Peng
Hui
H
Yang
Ming
M
Qin
Lan
L
Zhu
Zhen-Ping
ZP
Yang
Chun-Zheng
CZ
D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D018951:Antigens, CD20 / Q000276:immunology*; D017209:Apoptosis; D002455:Cell Division / Q000187:drug effects; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000494:pharmacology; D007128:Immunoglobulin Fragments / Q000494:pharmacology; D016393:Lymphoma, B-Cell / Q000473:pathology*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D018951:Antigens, CD20; D007140:Immunoglobulin Fab Fragments; D007128:Immunoglobulin Fragments; D011993:Recombinant Fusion Proteins