Abstract
The present study aimed to establish a novel method for efficiently inducing cytotoxic T lymphocytes (CTLs) in vitro, in order to develop an immune-based therapy for suppressing and killing ovarian cancer cells with a high safety and efficacy. Peripheral blood mononuclear cells (PBMCs) were stimulated with CpG oligodeoxynucleotide (CpGODN) and ginsenoside Rg1, which were united as an immune adjuvant, and human epidermal growth factor receptor 2 (HER2/neu) antigen peptide, in order to establish a specific CTL culture system in vitro. Chromosome karyotype analysis, growth curve construction and flow cytometric analysis of immune phenotypes, including cluster of differentiation (CD)3, CD4 and CD8, were performed to characterize the stimulated PBMCs in vitro. Subsequently, SKOV3 ovarian cancer cells were treated with the specific CTL culture system in vitro, and MTT assays were performed to test the inhibitory and lethal effects of the CTLs on SKOV3 cells. The number of CTLs was significantly increased from day 7 of stimulation with the specific mixture (CpGODN, ginsenoside Rg1 and HER2/neu) (P<0.01), and plateaued on day 19. Following activation, the number of CD3+, CD3+CD4+ and CD3+CD8+ cells was significantly increased (P<0.01). The lymphocyte karyotype did not change following exposure to antigen. After treatment with the specific CTL system, the number of SKOV3 cells in the experimental group was significantly reduced compared with that in the control group (P<0.01). The results of the present study suggested that two novel immune adjuvants, CpGODN and ginsenoside Rg1, could be combined with the HER2/neu antigen peptide to establish a specific CTL culture system in vitro. This system demonstrated a high antigen specificity, safety and proliferative ability, and exerted significant lethal and inhibitory effects on SKOV3 cells in vitro.