[Effect of CD(40) on the in vitro biological behavior of malignant B lymphocytes].
OBJECTIVE
To explore the effect of recombinant human soluble CD(40) ligand (rhsCD(40)L) and CD(40)L cDNA transfected cell (CD(40)L-TC) on the behavior of malignant B lymphocytes, and investigate the possibility of using rhsCD(40)L as a new bio-factor in tumor immunotherapy.


METHODS
rhsCD(40)L and CD(40)L-TC were obtained by gene recombinant techniques. Multiple myeloma cell lines, XG2, XG7, U266 and 8226, B-lymphoma cell lines, Raji and Daudi were selected to detect responses to rhsCD(40)L and CD(40)L-TC stimulation. Cell growth curve, cell cycle, early apoptosis as well as membrane surface molecules on these cell lines were analyzed.


RESULTS
(1) The expression levels of CD(40) molecule on malignant B lymphocytes showed heterogeneity. High level of CD(40) on XG2, moderate on 8266, Raji, and Daudi, and no expression on U266 and XG7 were detected. The rhsCD(40)L stimulation gave rise to a typical homo-type cell aggregation of XG2 and Daudi. Meanwhile, at least 10 to 20 of CD(40)(+) XG2 or CD(40)(+) Daudi cells were found adherent to one pre-treat ed CD(40)L-TC. (2) Co-incubation with rhsCD(40)L (5 micro g/ml), or CD(40)L-TC (tumor cell: CD(40) = 5:1) resulted in a significant inhibition of in vitro cell growth of XG2, Raji and Daudi, with G(1)-phase arrest for XG2 and G(2)-phase for Raji and Daudi. These two kinds of CD(40) stimulators induced XG2, Raji and Daudi cells to apoptosis in vitro. The apoptotic rate for XG2 was 23.3% (rhsCD(40)L) and 18.8% (CD(40)L-TC), for Daudi 14.2% and 15.9%, and for Raji 11.6% and 8.9% respectively. (3) Phenotype analysis showed that CD(95) expression levels were significantly up-regulated on XG2, Raji and Daudi after stimulation with rhsCD(40)L or CD(40)L-TC, and CD(80) and CD(18) expression levels on Raji were respectively enhanced and decreased.


CONCLUSIONS
The abilities to directly inhibit XG2, Daudi and Raji cell proliferation, to induce themapoptosis, as well as to up-regulate immune co-stimulator molecule CD(80) expression on Raji cells would make rhsCD(40)L a potential bio-factor for tumor immuno-therapy.
Shi
Hongzhen
H
Medical Biotech Institute, Life Sciences School of SuZhou University, Suzhou 215007, China.
Qi
Chunjian
C
Zhuang
Yumei
Y
Gu
Zongjiang
Z
Yu
Gehua
G
Zhao
Wenbao
W
Zhang
Xueguang
X
D001402:B-Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D019013:CD40 Antigens / Q000378:metabolism; D023201:CD40 Ligand / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D018920:Coculture Techniques; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D016393:Lymphoma, B-Cell / Q000378:metabolism / Q000473:pathology; D011994:Recombinant Proteins / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000187:drug effects
D019013:CD40 Antigens; D018076:DNA, Complementary; D011994:Recombinant Proteins; D023201:CD40 Ligand