Khranovska N. The role of dendritic cells in activation of antitumor immunity (experimental and clinical-immunological study)

The thesis is devoted to the top problem of oncology - development of the ways to obtain functionally active dendritic cells (DCs) and antitumor DC based vaccines, the rationale for their use and study of the effectiveness of vaccines in the treatment of non-small cell lung cancer (NSCLC) and ovarian cancer (OC) patients.Cancer vaccines based on DCs and components of devitalized tumor cells (CDTC) - lyophilized tumor cells (LPTC), modified (M) LPTC, lysate of tumor cells (LOC), LOC obtained under the influence of cytotoxic lectins (CL) of B. subtilis have been created. MLPTC has ability to activate DCs changing their phenotype, functional and cytomorphological properties. Modification triggers an increase of the LPTC microparticles surface asymmetry and the level of free radicals in tumor material by 100 times. DCs incubation in the presence of MLPTC for 4 h enhances their phagocytic activity by 24%. In experimental studies found that DCs based vaccine therapy is an effective method for metastasis burden decreasing and primary tumor growth inhibition. The most effective vaccines are DCs loaded with MLPTC and DCs loaded with LOCCL. Inoculating of DCs loaded with MLPTC or LOCCL contributes significant inhibition of the metastatic process: index of metastasis inhibition was 66-95% in mice with Lewis lung carcinoma after removal of the primary tumor and 99% in mice with B16 melanoma. Efficacy of DCs based vaccine therapy could be increased by optimizing the method of DCs loading by CDTC and choice of ways of DCs cells inoculation, and by combination of DCs vaccine with low doses of cyclophosphamide (CP) and interferon (IFN)-gama in the chemoimmunotherapy (CIT) regimen. Index of metastasis inhibition is 99% when CIT were used vs 45% when DCs vaccine was used and 95% when DCs vaccine were used in combination with CP. The most effective ways of DCs vaccines inoculation are intravenous (i/v) and intradermal (i/d). It was revealed that DCs of NSCLC and OC patients are characterized by an increased content of partially mature cells - reduced quantity of CD83+, CD86+,HLA-DR+ DCs in cancer patients DCs cultures in comparison with DCs cultures of healthy donors, intact mRNA expression of CCR7, reduced capacity for bioactive IL-12 production, increased levels of immunosuppressive molecules TGF-gama and IDO, which is significantly reduced at the stages of immunotherapy. Platinum based chemotherapy in OC patients adversely affects myeloid DCs maturation in 35% of cases. Violations observed in phenotypic maturation of DCs within 2 months after the chemotherapy. Possibility of DCs generation from monocytes of cancer patients and regulation of their functional properties by IFN-alfa with toll-like receptor (TLR) agonist has been shown. The combination of two activating signals - IFN-alfa and lipopolysaccharide (LPS) has no advantages in inducing of phenotypic maturation of monocyte derived 50 DCs versus activation only via LPS, but significantly affects cytokine and chemokine producing potential causing the dominance of proinflammatory potential (increased mRNA expression of IFN-gama, TNF-beta, RANTES and MIP-1).The schemes of DCs based vaccine therapy of patients with NSCLC IIIA stage and ovarian cancer (OC) IIB and III-IV stage have been elaborated. Vaccines were administered in the adjuvant setting after standard treatment to prevent recurrence and metastasis. The course of vaccine therapy consists of 4 DCs vaccine i/v inoculations with monthly interval followed by immunomonitoring after 1 month after each injection. Vaccine therapy contributes significantly to improving the results of NSCLC and OC standard treatment. Thus, during the 5-year follow-up period DC based vaccine increased the overall survival of patients with NSCLC by 25% (HR 0.47; 95: CI = 0.9-0.74), disease-free period - by 26% (HR 0.38; 95: CI = 0.24-0.61) in patients with OC - by 35% (HR 0.42; 95: CI = 0.23-0.77) and 30% (HR 0.54; 95: CI = 0.31-0.92), respectively. DCs based cancer vaccines are an effective modulator of the immune system of between Th1- and Th2- type of immune response have been occurred. Prognostic significance of immunological parameters - TGF-gama mRNA expression level, the number of CD4+CD45RO+ cells in circulation, the ratio of CD3+IFN-gama+/CD3+IL-4+ after incubation with CDTC has been revealed. Their value as specific immunological markers for predicting clinical efficacy of DC based vaccine therapy in patients with NSCLC has been proved.