1. Ana Ferreira no.58446 Marta Meneses no.58415 MEBM Instituto Superior Técnico Biomolecular and Cellular Engineering 2010/2011

2. W HAT IS A C ANCER ? WHEN A CELL OR A GROUP OF CELLS DISPLAY: Uncontrolled growth; Invasion; Metastasis (sometimes); IS INDUCED BY A SET OF GENETICAL MUTATIONS: Virus; Drugs; Radiation… 2

3. 3 Cancer Immunology Study of interactions between the immune system and cancer cells Recognition of cancer-specific antigens Knowledge gained drives the development of new vaccines and antibody therapies. Over the past 10 years there has been notable progress and an accumulation of scientific evidence for the concept of cancer immunosurveillance and immunoediting Protection against development of spontaneous and chemically-induced tumors in animal systems Identification of targets for immune recognition of human cancer

4. Protects the host from infectious pathogens, evolving mechanisms to generate a diverse repertoire of antigens-specific T and B cells. 4 A DAPTATIVE I MMUNE S YSTEM DISADVANTAGE It contains cells that are able to recognise and attack the host’s own tissues, but such cells are controlled and prevented from responding to self tissues. This is controled by a network of antigen-presenting cells (APC) Most important

5. Process antigen material and present it on the surface to other cells of the immune system 5 D ENDRITIC C ELLS FUNCTION Tissues that are in contact with the external environment, mainly in skin and the inner lining of the nose, lungs, stomach and intestines. THEY ARE PRESENT IN…

6. Tumors do not induce an effective inflammatory response conducive for optimal activation of DCs. 6 The primary purpose of vaccinating individuals with cancer is LIMITATIONS: They are administered therapeutically in the cancer patient in the face of a preexisting antigenic load (the tumor); Immune responses are suppressed in cancer patients

7. Immunize cancer patients with autologous, patient-derived DCs loaded with tumor antigens ex vivo. 7 S OLUTION

8. Inability to fully recapitulate activation process 8 Ex-Vivo generation of DCs Human DCs Generated from CD34 + hematopoietic progenitors Peripheral blood-derived monocytes GoalGoal Generate population of antigen-loaded DCs that stimulates robust and long-lasting CD4 + and CD8 + T cell responses Rate-limiting step

9. Activation Process Two stages In Periphery Immature DCs undergo maturation process 9 Response to inflammatory stimuli consequently DCs acquire capacity to home to lymph nodes ( migration) DC migration controlled by leukotrienes ( LTD4 and LTE4), which act downstream of CCR7 signaling Reaching the lymhp node,antigen-loaded mature DCs undergo other activation step - Licensing

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11. TLRs Pathogen-mediated maturation of DCs is mediated mainly through the TLRs that are expressed on immature DCs. Cytokines Cytokines are also capable of promoting DC maturation but cannot substitute for TLR stimulation. 11 E NHANCING DC M ATURATION PROBLEM

12. O PTIMAL EX V IVO DC M ATURATION : Require a combination of both cytokines and TLR ligands, with enhanced antitumor immunity and clinical efficacy. 12 Extending the persistence and presentation of antigen by DCs in the lymph node enhances the ensuing immune response. DCs that are presenting antigen in the lymph node are prone to elimination by their cognate T cells. Generating DCs expressing antiapoptotic proteins or using siRNA to decrease the expression of proapoptotic proteins should also potentiate their immunogenicity. METHODS TO ENHANCE DC VIABILITY

13. 13 Design of cancer vaccines Important things to consider Form of antigen used to load DCs How much antigen Efficiency of loading Persistence Timing Form of antigen Exogenous Peptides,whole protein, tumor lysate or complexed with antibody Endogenous Transfection with mRNA or cDNA encoding the antigen

14. 14 Antigen quantity, persistence and timing Design of cancer vaccines There is a discrepancy between the amount of antigen expressed by DC and stimulatory capacity of DC in vivo Immune system is high sensitive in detection of antigen at very low concentrations Immune system has the ability to respond to antien at low concentration Antigen loading increased Protective immunity in patient might be diminished It takes several hours for DCs to reach lymoh nodes There is a correlation between antigen persistence in DC and magnitude of immune response Nucleic acid-encoded antigens provide supply of antigen over an extended period of time Loading immature DCs is more effective than loading mature DCs

15. 15 Design of cancer vaccines Which antigens? Debated issue Broadly expressed, well defined antigens Antigenic mixtures More potent form of antigen More potent form of antigen Contains tumor-specific immunodominant antigens Contains tumor-specific immunodominant antigens

16. Targeting different cancers using different methods of generating DCs, different antigens, and different antigen-loading techniques. 16 C LINICAL T RIALS GOAL

17. How the cells are frozen and thawed; How long the cells are matured; At what speed they are centrifugated; The mechanisms of their administration; Time intervals between boostings. DC V ACINATION I MPORTANT S TEPS 17 IT CAN HAVE A CRITICAL IMPACT ON THE OUTCOME OF THE TREATMENT

18. Only a few DCs from the vaccination mixture migrate to the lymph node. 18 H OW C AN DC V ACINES B E I MPROVED ? SOLUTION Use a multineedle device The current consensus is that longer time intervals between boostings are better RECENT STUDIES More frequent vaccinations generate a long-lasting response

19. 19 Are DCs the ultimate professional APC to use in the setting of cancer vaccination with ex vivo–derived APCs? What about monocytes, B cells or γδ T cells? Are DCs the ultimate professional APC to use in the setting of cancer vaccination with ex vivo–derived APCs? What about monocytes, B cells or γδ T cells? Vaccination with ex vivo–generated DCs: is it worth the trouble? Vaccination with ex vivo–generated DCs: is it worth the trouble?