Stem Cell Institute Philippines

novel inductions for the future...

Natural Killer Cells Attack Cancer and Virus

Autologous Dendritic Cell Therapy for Cancer is available at ASCI.

Cancer represents one of the major causes of mortality worldwide. More than half of patients suffering from cancer succumb to their condition. The primary approaches to treating cancer are surgical resection followed by radiation therapy and chemotherapy. These treatments have resulted in significant benefits to patients with the majority of tumor types, and the clinical outcomes have become more satisfactory. It is recognized that multidisciplinary treatments should be used in cancer treatments, another option proposed for this is immunotherapy. The combination of the traditional methods of surgery, chemotherapy and radiotherapy with immunotherapy, is a new way for anti-cancer therapies to reduce the mortality of cancer patients. The dysfunction of the antigen-specific T cells required to kill the cancer leads to cancer cells being able to grow in cancer patients. Active and adoptive T cell immunotherapies generate T cells that can target cancer cells.

Dendritic cells (DCs) are immune cells that function as antigen-presenting cells. They are able to activate naive CD4+ T helper cells and unprimed CD8+ cytotoxic T lymphocytes. Active immunotherapy, represented by DC-based regimens, has been used to produce tumor-specific antigen-presenting cells and to generate cytotoxic T lymphocyte responses against cancer cells. DCs can capture antigens, process them, and present them with co-stimulation cytokines/messengers to initiate an immune response, like inducing primary T-cell responses.

Adoptive immunotherapy, as conducted at our Asian Stem Cell Institute, is a personalized therapy that uses a patient’s own anti-tumor immune cells to kill cancer cells and may be used to treat several types of cancer, and represents another therapeutic approach against cancer. To date, the adoptive immunotherapy approach is one of the most effective methods for using the body’s immune system to treat cancer. To be used clinically, protocols for the development of these functional DCs must be established for in-clinic use via defined, xenobiotic-free medium conditions.

The purpose of the present study is to determine the cellular immune response in terms of the delayed-type hyper-sensitivity (DTH) skin test and evaluate the subjective clinical outcome and safety of the regimen in cancer patients receiving a DC vaccine.

Vaccination against a single antigen is available using purified and synthetic products, but these have disadvantages because it is unknown which of the identified antigens have the potential to induce an effective antitumor immune response. This study uses unfractionated, autologous, tumor-derived antigens in the form oftumor cell lysates which circumvents this disadvantage.

Tumor lysates as addressed in this protocol, contain multiple known as well as unknown antigens that can be presented to T cells by both MHC class I- and class II-pathways. Therefore, lysate-loaded DCs are more likely to induce the more preferred polyclonal expansion of T cells, including MHC class II restricted T-helper cells. These have been recognized to play an important role in the activation of Cytotoxic T Lymphocytes (CTLs), probably the most important cells in effecting an antitumor immune response. The generation of CTL clones with multiple specificities may be an advantage in heterogeneous tumors and could also reduce the risk of tumor escape variants. Furthermore, lysate from the autologous tumor can be used independently of the HLA type of the patient. A drawback of unfractionated tumor antigens is the possibility of inducing an autoimmune reactivity to epitopes that are shared by normal tissues. However, in clinical trials using lysate or whole tumor cells as the source of antigen, no clinically relevant autoimmune responses have ever been detected.

Personalized dendritic cell vaccines for cancer, via adoptive immunotherapy, are successfully developed and autologously administered to patients coming to Asia, and more specifically, within the Philippines at the Asian Stem Cell Institute in Manila. The results of this case study of cancer and immunotherapy via pulsed dendritic cells, can serve as another example of safety for future cancer vaccine development.

 

Dendritic Cell Therapy for Cancer:
Related Articles Tumor immune microenvironment characterization in clear cell renal cell carcinoma identifies prognostic and immunotherapeutically relevant messenger RNA signatures. Genome Biol. 2016 Nov 17;17(1):231 Authors: Şenbabaoğlu Y, Gejman RS, Winer AG, Liu M, Van Allen EM, de Velasco G, Miao D, Ostrovnaya I, Drill E, Luna A, Weinhold N, Lee W, Manley BJ, Khalil DN, Kaffenberger SD, Chen Y, Danilova L, Voss MH, Coleman JA, Russo P, Reuter VE, Chan TA, Cheng EH, Scheinberg DA, Li MO, Choueiri TK, Hsieh JJ, Sander C, Hakimi AA Abstract BACKGROUND: Tumor-infiltrating immune cells have been linked to prognosis and response to immunotherapy; however, the levels of distinct immune cell subsets and the signals that draw them into a tumor, such as the expression of antigen presenting machinery genes, remain poorly characterized. Here, we employ a gene expression-based computational method to profile the infiltration levels of 24 immune cell populations in 19 cancer types. RESULTS: We compare cancer types using an immune infiltration score and a T cell infiltration score and find that clear cell renal cell carcinoma (ccRCC) is among the highest for both scores. Using immune infiltration profiles as well as transcriptomic and proteomic datasets, we characterize three groups of ccRCC tumors: T cell enriched, heterogeneously infiltrated, and non-infiltrated. We observe that the immunogenicity of ccRCC tumors cannot be explained by mutation load or neo-antigen load, but is highly correlated with MHC class I antigen presenting machinery expression (APM). We explore the prognostic value of distinct T cell subsets and show in two cohorts that Th17 cells and CD8(+) T/Treg ratio are associated with improved survival, whereas Th2 cells and Tregs are associated with negative outcomes. Investigation of the association of immune infiltration patterns with the subclonal architecture of tumors shows that both APM and T cell levels are negatively associated with subclone number. CONCLUSIONS: Our analysis sheds light on the immune infiltration patterns of 19 human cancers and unravels mRNA signatures with prognostic utility and immunotherapeutic biomarker potential in ccRCC. PMID: 27855702 [PubMed - indexed for MEDLINE]
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Related Articles Absence of γ-chain in keratinocytes alters chemokine secretion resulting in reduced immune cell recruitment. J Invest Dermatol. 2017 Jun 17;: Authors: Nowak K, Linzner D, Thrasher AJ, Lambert PF, Di WL, Burns SO Abstract Loss of function mutations in the common gamma (γc) chain cytokine receptor subunit give rise to severe combined immunodeficiency (SCID) characterised by lack of T and natural killer cells and infant death from infection. Haematopoietic stem cell transplantation or gene therapy offer cure but despite successful replacement of lymphoid immune lineages a long-term risk of severe cutaneous human papilloma virus (HPV) infections persists, possibly related to persistent γc-deficiency in other cell types. Here we demonstrate that keratinocytes, the only cell type directly infected by HPV, express functional γc and its co-receptors. Following stimulation with the γc-ligand IL-15, γc-deficient keratinocytes demonstrate significantly impaired secretion of specific chemokines including CXCL1, CXCL8 and CCL20 resulting in reduced chemotaxis of dendritic cells and CD4+ T-cells. Furthermore, γc-deficient keratinocytes also exhibit defective induction of T-cell chemotaxis in a model of stable HPV18 infection. These findings suggest that persistent γc-deficiency in keratinocytes alters immune cell recruitment to the skin which may contribute to the development and persistence of warts in this condition and would require novel treatment approaches. PMID: 28634034 [PubMed - as supplied by publisher]
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Immunogenicity of AGS-004 Dendritic Cell Therapy in Patients Treated During Acute HIV Infection. AIDS Res Hum Retroviruses. 2017 Jun 21;: Authors: Gay CL, DeBenedette MA, Tcherepanova IY, Gamble A, Lewis WE, Cope AB, Kuruc JD, McGee KS, Kearney MF, Coffin JM, Archin NM, Hicks CB, Eron JJ, Nicolette CA, Margolis DM Abstract AGS-004 consists of matured autologous dendritic cells co-electroporated with in vitro transcribed RNA encoding autologous HIV antigens. In an open-label, single arm sub-study of AGS-004-003, AGS-004 was administered monthly to suppressed participants who started antiretroviral therapy (ART) during acute HIV infection. HIV-1 specific T cell responses were measured by multicolor flow cytometry after 3-4 doses. The frequency of resting CD4(+) T-cell infection (RCI) was measured by quantitative viral outgrowth assay. Participants demonstrating increased immune response postvaccination were eligible for analytic treatment interruption (ATI). AGS-004 induced a positive immune response defined as ≥2-fold increase from baseline in the number of multifunctional HIV-1 specific CD28(+)/CD45RA(-) CD8(+) effector/memory cytoxic T-lymphocytes (CTLs) in all six participants. All participants underwent ATI with rebound viremia at a median of 29 days. Immune correlates between time to viral rebound and the induction of effector CTLs were determined. Baseline RCI was low in most participants (0.043-0.767 IUPM). One participant had a >2-fold decrease (0.179-0.067 infectious units per million [IUPM]) in RCI at week 10. One participant with the lowest RCI had the longest ATI. AGS-004 dendritic cell administration increased multifunctional HIV-specific CD28(+)/CD45RA(-) CD8(+) memory T cell responses in all participants, but did not permit sustained ART interruption. However, greater expansion of CD28(-)/CCR7(-)/CD45RA(-) CD8(+) effector T cell responses correlated with a longer time to viral rebound. AGS-004 may be a useful tool to augment immune responses in the setting of latency reversal and eradication strategies. PMID: 28636433 [PubMed - as supplied by publisher]
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