The Experimental Study Of Treating Malignant Tumor With Recombinant Adenovirus Vector Containing Human MIP-1( Gene

Macrophage inflammatory protein-1 beta (MIP-1() is a new chemokine which has strong chematactic activity for T cells, B cells, mononeuclears, neutrocytes, dendritic cells and so on. MIP-1( involves in the activation and accumulation of lymphocytes and mononeuclears in tumor site and launchs efficient anti-tumor efforts. The effects of recombinant replication deficient-adenovirus containing human MIP-1( gene (AdhMIP-1() on the activation of systemic anti-tumor response were investigated in the present study. The hMIP-1( gene was transfected into murine CT26 colorectal adenocarcinoma cells by adenovirus , the level of hMIP-1( in the superntant of CT26 cells transfected with hMIP-1( gene (CT26-hMIP-1() was assayed and the change of biological peculiarities of CT26-hMIP-1( cells was observed .The BALB/C mice were immunized with CT26-hMIP-1( vaccine and the antitumor efforts were investigated; The treatment effects of injection of AdhMIP-1( into tumor nodules derived from the CT26 murine colorectal adenocarcinoma cells line were assayed and the antitumor immunological mechanism was probed. The results showed that: (1) hMIP-1( gene could be transfected into murine CT26 colorectal adenocarcinoma cells by AdhMIP-1( with efficiency over 95%. The level of hMIP-1( in the culture supernatant of CT26-hMIP-1( was 980pg/1(106cells/24h. This supernatant showed strong chematactic activity for CD8+ T cells, CD4+ T cells and NK cells. The growth rate of the CT26-hMIP-1( cells versus the parental CT26 cells didn't show any difference. When the CT26-hMIP-1( cells were subcutaneously injection into BALB/C mice, tumorigencity was delayed and suppressed, showing the potential immune responses. Histological examination of the modified tumor masses implanted with the tumor cells expressing hMIP-1( gene showed that the increase of necrosis and infiltration of lymphocytes. (2) The growth of rechallenged wild-type CT26 cells was more suppressed in the mice which were immunized with CT26- hMIP-1( vaccines. Detection the phenotype of that the various immunized splonocytes with FACS showed the ratio of CD4/CD8 T cells significantly decreased and the percentage of CD25 increased markedly in the mice which were immunized with CT26-hMIP-1( vaccines. Our results showed a dramatic increase in anti-CT26 CTL activity upon the mice which were immunized with CT26-hMIP-1( vaccines. (3) The treatment of injection of AdhMIP-1( into tumor nodules derived from CT26 cells line displayed that AdhMIP-1( transfection significantly inhibited the tumor growth and prolonged the survival time of tumor-bearing mice, and induced tumor regression in 2 of 8 cases. The result of the study on antitumor immunological mechanism showed that tumor cells could be transfected with hMIP -1( mediated by AdhMIP-1( and the secretion of hMIP-1( strongly attracted a great deal of immune function cells (including T cells, NK cells, mononeucleacs and so forth) in tumor site, then generated a powerful specific and nonspecific antitumor response. In vivo depletion of immune cell subsets with mAbs demonstrated that the antitumor response depended on both CD8+ T cells and CD4+ T cells.In summary, the present study suggested that the tumor vaccines modified with hMIP-1( gene play a potent role in preventing the metastasis and recurrence of malignant tumor. Intratumoral injection of AdhMIP-1( is a safe, reliable, simple and practical way of gene therapy for malignant tumor.