Preparation of HL-60 cell vaccine expressing BCG-HSP70 and its anti-leukemia effect / 临床儿科杂志

ABSTRACT

Objectives To prepare the HL-60 cell vaccine expressing heat shock protein 70 (HSP70) of Bacille calmette-Guérin (BCG), so as to study its anti-tumor effect and mechanism. Methods The whole BCG HSP70 gene was amplified from BCG genome by polymerase chain reaction (PCR) and sub-cloned into the polyclone endonuclease sites in pDisplay. The recom-binant vector of pDisplay-HSP70 was verified by sequencing. Then the HL-60 cell vaccine expressing the protein onto the cell surface was prepared by lipofectamine transfection. To detect the immunogenicity of HL-60 cells expressing HSP70, the test groups were divided into three subgroups, HL60-wt, HL60-pDisplay, and HL60-HSP70 respectively. Each group was cultured with peripheral blood T cells for 72 h, then the proliferation indices of T cells were assayed by CFSE-staining method, and IFN-γwere tested by enzyme-linked immunosorbent assay (ELISA). The HL-60 cells of different groups were cultured with peripher-al blood T cells for 6d. The wild-type HL-60 cells were added and co-cultured for another 12h. Cytotoxicity assay was measured by LDH release. Results (1) The fragment of BCG HSP70 was consistent with the theoretical value. DNA sequencing showed that the recombinant vector of pDisplay-HSP70 was correctly constructed. (2) BCG HSP70 expressed onto the HL-60 cells sur-face. (3) Detection of the immunogenicity ①The most significant T cell proliferation was observed in the group of HSP70-transfected HL-60 cells (P0.05).②The contents of IFN-γof the HSP70-HL60 group was the highest.③The inhibiting activity of CTLs on HL-60 cells in the group of HSP70-transfected HL-60 cells was more significant than that of wide-type and pDisplay--transfected HL-60 cells. And with the increase of the ET ratio, the inhibiting activity of CTLs in the HSP70-HL60 group was rising. Conclusions The recombinant eukaryotic expression vector (pDisplay-HSP70) of BCG HSP70 was successfully constructed. And the HL-60 cell vaccine expressing BCG HSP70 onto its surface was successfully prepared. The results showed that gene transfection of BCG HSP70 could significantly enhance the immunogenicity of HL-60 cells.