Study On The Mobilization Of Dendritic Cell Precursors By Administration Of Chemokine MIP-1α And Its Application For Gastric Cancer Therapy

Objective: This study was designed to investigate mobilization of dendritic cells into the circulation by administration of macrophage inflammation protein-1α (MIP-1α), furthermore, explore the mechanisms on their mobilization and traffic. Then, study on DC-based anti- gastric cancer efficacy.Methods: C57BL/6 (B6, WT) mice were injected, via the tail vein, with MIP-1α. Peripheral blood was obtained at the different time intervals after MIP-1α injection. Peripheral blood mononuclear cells (PBMNCs) were prepared from peripheral blood. F4/80^-B220^-CD11c⁺ cells were sorted from these PBMNCs by FACS. Then compare the quantitive change of F4/80^-B220^-CD11c⁺ cells in the PBMNCs. B6 mice were injected with the different dose MIP-1α. After 24 hours, F4/80^-B220^-CD11c⁺ cells were obtained from PBMNCs. Analyses the quantitve difference of F4/80^-B220^-CD11c⁺ cells. B6/WT, CCR1^-/-, and CCR5^-/- mice were injected with MIP-1α. After 24 hours, PBMNCs were prepared from peripheral blood, then F4/80^-B220^-CD11c⁺ cells were sorded by FACS. Compare the quantitive difference of F4/80^-B220^-CD11c⁺ cells among the different mice. (2) Freshly isolated F4/80^-B220^-CD11c⁺ cells and F4/80^-B220^-CD11c⁺ cells cultured with cytokines mGM-CSF, IL-4, and mTNF-α were analysed by morphological observation, phenotype analysis, and mixed lymphocyte reaction (MLR). (3) DC mobilized by MIP-1α injection were loaded with gastric cancer antigen obtained by frozen and thawed. Then the kill effect of T cells stimulated with those DC to gastric cancer cells was evaluated.Results: (1)F4/80^-B220^-CD11c⁺ cells increased in circulation 4h after MIP-1α injection, then gradually reached a peak level 24 hour after injection, account for13.31%±1.27% among PBMNCs. When the dose of MlP-la injection was 20|xg/per, F4/80^B220^CDllc+ cells reached a peak level (account for 13.29%±1.1% among PBMNCs). F4/80^B220^CDllc+ cells were higher in B6 mice (account for 13.47%±1.4% among PBMNCs), than in CCRl"7" and CCR5"'" (10.55%±0.79% and 5.87%±0.48%, respectively, both P < 0.01). (2)Freshly isolated F4/80"B220"CDllc+ cells did not show the character of mature DC. F4/80"B220^CDllc+ cells cultured with cytokines mGM-CSF, IL-4, and mTNF-oc were morphologically and phenotyically identical to typical DC, gained the capacity to stimulate allogeneic T cells. (3)T cells stimulated with MlP-la mobilized-DC loaded gastric cancer antigen showed the specific kill effect on gastric cancer cells.Conclusion: (1) A single administration of MlP-la could rapidly mobilize F4/80^B220^CDllc+ DC precursors into peripheral blood, and these cells can differentiate into mature DC in vitro. (2) The interaction of MlP-la and its receptors, CCRl and CCR5, mediated DC precursors into circulation. (3) DC mobilized by MlP-la injection can induce specific CTL to gastric cancer cells.