Superantigen-SEA gene modified tumor vaccine for hepatocellular carcinoma: Anin vitrostudy

Abstract

AIM:To construct an eukaryotic superantigen gene expression vector containing the recombinant gene of SEA and CD80 molecule transmembrane region (CD80TM), and to express staphylococcus enterotoxin A (SEA) on the membrane of hepatocellular carcinoma (HCC) cell to form a superantigen gene modified tumor vaccine for HCC. METHODS:SEA and linker-CD80TM gene were amplified through PCR from plasmid containing cDNA of SEA and CD80. Gene fragments were then subcloned into the multiple cloning sites of retroviral vector pLXSN. Recombinant plasmid was transferred into HepG2 cells mediated with lipofectamine, positive clones were selected in culture medium containing G418. RT-PCR and indirect immunofluorescence studies confirmed that SEA was expressed specifically on HCC cell membrane. INFγ-ELISPOT study demonstrated that SEA protein was expressed on the membrane of HCC cells. Cytotoxicity of HepG2-SEA primed CTLs (SEA-T) was analyzed by 51 Cr release assay. T cells cultured with rhIL-2 (IL-2-T) were used as control. RESULTS:Restriction digestion and sequence analyses confirmed the correctness of length, position and orientation of inserted fusion genes. SEA was expressed on the surface of HepG2 cells, HepG2-SEA had strong stimulating effect on production of HepG2 specific CTL (P<0.001). SEA-T had enhanced cytotoxicity to HepG2 cells (P<0.05). CONCLUSION:Tumor cell membrane expressed superantigen can be used to reinforce the immune effect of tumor cell vaccine for HCC, which provides a new method of the enhanced active immunotherapy for HCC.

Recombinant Staphylococcal Enterotoxin Type A Stimulate Antitumoral Cytokines

“… 9 In another study, Lu and colleagues found that the construct obtained from fusing cloned-SEA into pLXSN with linker-CD80TM can be used as an antitumor agent. 26 The studies of Yue et al and Xu et al used pET42b (+) and pET-22b (+) as expression vectors for cloning of SEA, respectively; they also used BL21(DE3) as an expression host, 27 , 28 whereas in our study, entA gene was cloned into the pET-21a vector and we believe that, this is the first report of expression of entA gene into pET-21a as an expression plasmid; also in our study, BL21(DE3) was used as an expression host like the other study mentioned above.…”

Preparation and In Vitro Evaluation of Antitumor Activity of TGFαL3-SEB as a Ligand-Targeted Superantigen

“…T-cells have multifarious antitumor effects via releasing tumor-suppressive cytokines (interferon γ [IFN-γ] and tumor necrosis factor α [TNF-α]) or cytotoxic effector molecules such as perforin, 22,25 –27 but generally the number of tumor-specific T-cells is insufficient to mediate potent antitumor responses against progressive tumor growth. 34…”

Immune reaction characteristics and the mechanism of anergy induced by recombinant enterotoxin a of Staphylococcus aureus

“…Their efficacy has also been considered superior to exogenous cell factor. With the development of relevant theory, superantigens have attracted much attention of studies [1,2]. Earlier studies applied superantigens independently in anticancer therapy.…”