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Yonsei Medical Journal 2004;45(Suppl):S48-S52

Dendritic cells (DCs) play a pivotal role in T cell-mediated immunity and have been shown to induce strong antitumor immune responses in vitro and in vivo. Various approaches utilizing different vaccine cell formats, cell numbers, vaccination schedule, site of vaccination and maturation stages of DCs were investigated worldwide. While clinical trials have demonstrated the safety of such strategies, the clinical outcome was less than expected in most cases. This is due to in part host immunodeficiency imposed by tumors and immunoediting of tumor cells. To overcome these obstacles, new approaches to improve DC-mediated immunotherapeutic strategies are under investigation. First, functional enhancement of monocyte-derived DCs can be generated with using flt3-ligand (FL). Second, diverse antigenic determinants from heat shock-treated tumor cells may improve the immunogenicity of DC-based vaccines. Third, inclusion of ex vivo expanded NK/NKT cells in DC-based vaccines could be beneficial since the bidirectional interaction of these two cell types are known to enhance NK cell effector function and to induce DC maturation. Application of these approaches may induce a broadened antitumor immune response and thereby promote the elimination of tumor antigen-negative variant clones that had escaped immunosurveillance or undergone immunoediting. We are currently examining the feasibility of these immunotherapeutic approaches using a murine pancreatic cancer model system.
Animals ; Dendritic Cells/*immunology ; Humans ; Immunotherapy/*methods/*standards ; Neoplasms/*therapy

6.The potential of avian cytokines as immunotherapeutics and vaccine adjuvants.

Jian-He SUN ; Ping LU

Chinese Journal of Biotechnology 2003;19(2):141-146

With the imminent and widespread ban of the use of antibiotic feed additives and chemical antimicrobials in food production animals, alternative measures need to be sought to ensure that the livestock industry will not be adversely affected. Cytokines are proteins that control the type and extent of an immune response following infection or vaccination. They therefore represent excellent naturally occurring therapeutics. The identification, cloning and characterisation of cytokine genes in chickens have lagged somewhat behind similar work in mammals. Progress in isolating chicken homologues of mammalian cytokines has also been slowed by the generally low level of sequence similarity. Chicken cytokine genes that have been cloned to date include ChIFN-gamma, ChIL-1beta, ChIFN-alpha, ChIL-15, ChIL-18, ChIL-8, ChIL-2, ChIL-6, ChIL-16, SCF, MGF, TGFbeta, Lymphotactin, MIP-1beta, CXC and CC chemokines, so the use of cytokines in poultry has become more feasible with the discovery of a number of avian cytokine genes. The delivery methods for chicken cytokine are of prime importance and are required to be safe, easy to administer and cost-effective. Live viral vectors such as fowl adenovirus (FAV) expressing cytokine genes can be delivered via drinking water or aerosol sprays, making it very easy to administer. Since the immune system of chickens is similar to that of mammals, they offer an attractive model system to study the effectiveness of cytokine therapy in the control of disease in livestock. This review focus on the recent advances made in avian cytokines, with a particular focus on their assessment as therapeutic agents and vaccine adjuvants.
Adjuvants, Immunologic ; metabolism ; Animals ; Cytokines ; genetics ; immunology ; metabolism ; Immunotherapy ; methods