In vitro anti-tumor immune mechanism of nasopharyngeal carcinoma bispecific anti-idiotype antibody.
OBJECTIVE
To compare the in vitro antitumor immune responses induced by bivalent bispecific anti-idiotype antibody G22-I50 and monovalent anti-idiotype antibody G22 and I50, and explore its possible mechanism.


METHODS
Proteins G22-I50, G22, and I50 were induced and identified by Western blot and ELISA. Peripheral blood monoclear cells (PBMC) were isolated and stimulated with G22-I50, G22, and I50 anti-idiotype antibodies, respectively. MTT assay and LDH release test were employed to examine the proliferation and cytotoxicity of the PBMC. The levels of IFN-gamma, IL-2, and IL-4 in the supernatant were detected by ELISA and changes of T lymphocyte subsets were determined by flow cytometry.


RESULTS
Western blot showed that G22-I50, G22, and I50 had specific binding capabilities to FC2 (Ab1). The activities of G22-I50, G22, and I50 had recovered and these proteins could be used in the in vitro study. The proliferation and cytotoxicity of the PBMC stimulated with G22-I50 were significantly higher than those stimulated with G22 or I50. The level of IFN-gamma and IL-2 in the culture supernatant of the PBMC stimulated with G22-I50 was higher than that in the G22 or I50 group, but the level of IL-4 did not increase. Compared with the G22 or I50 group, the proportion of CD4(+) and CD8(+) T cells and CD4(+)/CD8(+) ratio significantly increased, and the proportion of CD4(+)CD25(+) T cells significantly decreased in the PBMC stimulated with G22-I50.


CONCLUSIONS
G22-I50 has more potent immunogenicity and would enhance specific antitumor effect which might relate to improving PBMC proliferation, inducing the secretion of Th1 type cytokines, activating CD8(+)T cells, and suppressing the expression of CD4(+)CD25(+) T cells.
Wang
Jiajia
J
Cancer Research Institute, Central South University, Changsha 410078, China.
Li
Yalin
Y
Li
Yuehui
Y
Li
Guancheng
G
D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000912:Antibodies, Neoplasm / Q000276:immunology*; D000918:Antibody Specificity; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology
D000888:Antibodies, Anti-Idiotypic; D000912:Antibodies, Neoplasm