How does the immune “security patrol” checking the body determine that all is well (or not well?) IT INSPECTS CELL SURFACE ANTIGENS Cells have distinct landmarks on their surfaces (antigens) that generally betray the nature of the cell within - normal or malignant, or is it infected with a virus?
B Cell Preeminent Cells of The Immune System T Cell Dendritic Cell Antibodies Humoral Immune System Cellular Immune System
T Cells The Major Player Responsible for Elimination of both Tumors and Viruses One trillion T cells in the human body
Two Types of T Cells The Killer T-cell (cytotoxic or cytolytic T-cell) The Helper T-cell.
Helper T Cells Unlike Killer T-cells, helper T-cells are not assassins. Like football quarterbacks, they are calling the plays of the immune response They tell Killer T cells and B cells what cells to attack
Killer T Cells Ability to identify and destroy cells harboring both viruses and cancers.
The Dendritic Cells Master Controllers of Immunity Dendritic cells are specialized for: Capture of antigens Processing of antigens into small fragments (peptides) Presentation of the peptides at their cell surfaces in association with MHC molecules so that an appropriate T cell can recognize the peptide-MHC complex and be activated
THE PROCEDURE IS READILY ADOPTABLE FOR CLINICAL USE Leukapheresis Intratumoral Injection Dendritic Cells Cryotherapy 1 2 3
RATIONALE Tumor Damage (Chemo/Cryo) Followed by Intratumoral Injection of Dendritic Cells After treatment with Cryo/Chemotherapy: -Dying (apoptotic/necrotic) tumors cells release multiple tumor antigens and “danger signals” -Intratumorally injected immature dendritic cells aquire tumor antigens in situ -Dendritic cells become activated, mature and migrate to the regional lymph nodes to set in motion anti-tumor activity of Tcells
Studies of Chemotherapy + Intra-tumoral Injection of DCs 1 2 3 1.Tanaka F, et al. Int J Ca 101:265-9, 2002. 2.Song W, Levy R. ASCO 2004 #2509. 3.Tong, et al. Ca Res 61:7530-5, 2001.
Tumor debulking Reduction of Immunosuppresive factors Increase antigen availability Intratumoral dendritic cell injection Uptake of tumor antigens from apoptotic & necrotic tumor cells Generation of immune response against tumor cells Systemic elimination of remaining tumors Cryotherapy
ADVANTAGES Cryo/Chemotherapy + Intratumoral Injection of Dendritic Cells Multiple antigens naturally selected from patient’s tumor by patient’s own dendritic cells Antigen-loading and maturation of dendritic cells occurs in vivo No need to search for tumor antigens (cost reduction) Combination with conventional cryotherapy (a standard care) which also reduce tumor burden
WHY CRYOTHERAPY? Freezing (cryotherapy) as a treatment for cancer has been around since the 1930s. During the last decade, cryotherapy technologies have been markedly improved and are becoming choice treatments for many different cancers. Unlike radiation and chemotherapy, cryotherapy does not damage the immune system and it can be repeated time and again.
Method of Action Cryotherapy results in massive tumor cell breakdown without damaging the immune system. This gives rise to innumerable antigens. Process can be repeated. Then, direct injection into the frozen tumor of millions of dendritic cells. The dendritic cells gobble up this mass of diverse antigens, and sensitize T cells that leads to tumor killing. Process can be repeated.
Human Phase I Trials in Progress Tumor Damage Followed by Intratumoral Injection of Autologous, Non-Loaded DCs Stanford University (liver cancer, thermal ablation). Sangretech Asia, Manila, The Philippines (prostate cancer, cryotherapy)
Cryoablation/Intra-Tumoral DC Combination cryoablationintra-tumoral DC injection uptake of dying tumor cells migration to lymph nodes and tumor-specific T cell activation tumor bed Benjamin Tjoa 2004
Conclusion The immunotherapy illustrated is essentially non-toxic. Can be added to other standard treatments Can be repeated time and again. Results in animals and humans are promising. It may be the only way to control metastatic disease?