We thank Ms. Deborah Postiff and Ms. Jackline Barikdar in the Tissue Procurement Core and Dr. Cindy DeLong in the Pluripotent Stem Cell Core Laboratory at the University of Michigan for her technical assistance. This study was supported by University of Michigan startup funding and grants from the Central Surgical Association, American College of Surgeons, Melanoma Research Alliance, and NIH/NCI (1K08CA197966-01) to F. Ito.

NOTE: Patients should give informed consent to participate in the Institutional Review Board and Human Pluripotent Stem Cell Committee approved study.
1. Isolation and Culture of TILs
<ol>
	<li>Obtain tumor material that is not required for histopathologic diagnosis from the pathology service/tissue procurement core. Place 20-100 g of tumor specimens in a 50-ml tube with 30 ml tumor collecting media (Table 1).</li>
	<li>Dissect solid, firm, normal tissue of the tumor specimen from fragile and/or bloody necrotic areas using scissors. After removing the necrotic tissue, use the scissors to mince the specimen as small as possible.</li>
	<li>Dissociate the minced specimen into a single-cell suspension using a dissociator and tumor dissociation kit (human) according to the manufacturer&#39;s instructions. Filter the suspension with a 70 &#181;m cell strainer that is set on a 50 ml tube and wash the strainer 2 times with 2 ml of RPMI 1640.</li>
	<li>Centrifuge at 200 x g at room temperature for 5 min. Discard the supernatant and resuspend the cells in 10 ml of T cell media (Table 1).</li>
	<li>Prepare a two-step gradient solution such as Ficoll (gradient solution) in a 50-ml tube, with a lower step of 10 ml of 100% gradient solution and a middle step of 30 ml of 75% gradient solution diluted with Dulbecco&#39;s phosphate-buffered saline, no calcium, no magnesium (D-PBS(-)).</li>
	<li>Layer the cell suspension (from Step 1.4) on the gradient solution (from Step 1.5). Centrifuge at 400 x g at 20 &#176;C for 45 min.</li>
	<li>Collect the layer containing the enriched TILs at the interface between the 100% gradient solution and the 75% gradient solution in a 50 ml tube. Dilute the layer of the solution with the enriched TILs by adding 20-30 ml of D-PBS(-).</li>
	<li>Centrifuge at 200 x g at room temperature for 5 min. Discard the supernatant and resuspend the TIL-enriched fraction in 10 ml of T cell media.</li>
	<li>Culture the fraction (from Step 1.8) with 2 ml of T cell media and 6,000 IU/ml recombinant human (rh) IL-2 in a 6-well plate at 37 &#176;C, 5% CO2.</li>
	<li>Change half the media on day 5 after culture initiation and every 2-3 days thereafter.</li>
	<li>Split the cells at a ratio of 1:2 without trypsinization after softly suspending, doubling the number of wells when reaching 80-90% confluency. Add a half volume (1 ml) of fresh T cell media and rhIL-2 at 6,000 IU/ml.</li>
</ol>
2. Preparation of Mitomycin-C-treated SNL Feeder Cell Plate
<ol>
	<li>Culture SNL feeder cells in 10 ml of SNL feeder cell media (Table 1) on a 0.1% gelatin-coated 10 cm dish until 80-90% confluence (3-4 x 106 cells) is reached.</li>
	<li>Add 310 &#181;l of 0.4 mg/ml mitomycin C solution directly into the SNL feeder cell culture dish and incubate at 37 &#176;C, 5% CO2 for 2 hr and 15 min. Aspirate the media and wash the cells twice with 5 ml D-PBS(-).</li>
	<li>Add 0.5 ml of 0.25% trypsin/1 mM EDTA and incubate at room temperature for 1 min to dissociate the cells. Add 4.5 ml of SNL feeder cell media to neutralize and re-suspend the cells into a single suspension.</li>
	<li>Transfer the cells into a 15 ml tube and centrifuge at 200 x g for 5 min. Aspirate the media and count the cells with a hemocytometer after re-suspending in 10 ml of SNL feeder cell media.</li>
	<li>Plate 1.5 x 106 cells per well of the SNL feeder cells on a 10 cm dish and incubate at 37 &#176;C, 5% CO2. Use the SNL feeder cells within 3 days.</li>
</ol>
3. Generation of iPSCs Using the Sendai Virus (SeV) Vector
<ol>
	<li>Harvest the TILs (from Step 1.11) and activate 5 x 105 cells of TILs with plate-bound mouse anti-human CD3 (1 &#181;g/ml) and soluble mouse anti-human CD28 (5 &#181;g/ml), with rhIL-2 (6,000 IU/ml) in 2 ml of T cell media in a 6-well plate at 37 &#176;C, 5% CO2 for 5 days.</li>
	<li>Harvest the TILs (from Step 3.1) in a 15 ml tube using a pipette and count the cell number with a hemocytometer.</li>
	<li>Reactivate 1 x 105 cells of TILs with plate-bound mouse anti-human CD3 (1 &#181;g/ml) and soluble mouse anti-human CD28 (5 &#181;g/ml), with rhIL-2 (60 IU/ml) in 500 &#181;l of reprogramming media (Table 1) per well in a 24-well plate at 37 &#176;C, 5% CO2 for 24 hr. Prepare 3 wells for SeV infection: OCT3/4, SOX2, KLF4, and c-MYC (1 well); SeV infection (GFP: green fluorescent protein) (1 well); and cell count (1 well).</li>
	<li>After 24 hr (from Step 3.3), count the cell number with a hemocytometer and determine the volume of each virus for various (3-20) multiplicities of infection (MOI). Remove one set of Sendai virus vector tubes from the -80 &#176;C storage. Thaw the SeV vectors quickly in a water bath (37 &#176;C) and place them on ice. 
	Volume of virus (&#181;l) = MOI (CIU/cell) x number of cells/titer of virus (CIU/ml) &#215; 10-3 (&#181;l/ml)</li>
	<li>Add the calculated volumes of each of the four Sendai virus vector tubes that individually carried OCT3/4, SOX2, KLF4, and c-MYC by adding a mixture of SeV vectors at 10-20 MOI into the media, including activated TILs.</li>
	<li>To determine the transduction efficiency, add the calculated volumes of SeV-GFP into a well of activated TILs.</li>
	<li>Place the dish (from Step 3.5 and Step 3.6) in the incubator at 37 &#176;C, 5% CO2 for 24 hr. After 24 hr, estimate the infection efficiency using TILs infected with SeV-GFP under fluorescence microscopy.</li>
	<li>Collect the cells (from Step 3.5) in a 15 ml tube. Centrifuge at 200 x g at room temperature for 5 min.</li>
	<li>Discard the supernatant and resuspend the pellet in 0.5 ml of hESC media with Primate ES Cell Medium and basic fibroblast growth factor (bFGF, 4 ng/ml).</li>
	<li>Transfer the suspension into a 10 cm dish that contains mitomycin-C-treated SNL feeder cells in 10 ml of hESC media. Change the hESC media every other day until the colonies are grown.</li>
	<li>Around day 18 to 21, remove the SNL feeder cells around the colonies under a microscope using a 10-&#181;l tip in the clean bench.</li>
	<li>Scrape the colonies using a 10-&#181;l tip and transfer them using a 200-&#181;l tip into 100 &#181;l of iPSCs media per well of a 96-well tissue culture plate. Pipet up and down at 2-3 times to break the colonies into small clumps with an average size of 50-100 &#181;m.</li>
	<li>Transfer the small clumps into 6-well tissue culture plates with mitomycin-C-treated SNL feeder cells (from Step 2) in 2 ml per well of iPSCs media with basic fibroblast growth factor (bFGF, 4 ng/ml). Change iPSCs media every day.</li>
	<li>Transfer the iPSCs to 6-well tissue culture plates with fresh mitomycin-C-treated SNL feeder cells with 1 mg/ml collagenase IV every 5-6 days. Prepare 2 wells per plates of each clone for immunostaining.</li>
	<li>Determine the full reprogramming of each clone by immunohistochemical staining of pluripotency markers (SSEA3, SSEA4, TRA-1-60, TRA-1-81, and OCT3/4)1. 
	NOTE: For further evaluation of pluripotency potential, confirm that fully-reprogrammed iPSC lines can differentiate into three germ layers by an embryoid body formation and differentiation assay or a teratoma formation assay16.</li>
	<li>Confirm that fully-reprogrammed iPSC lines demonstrate a normal karyotype by cytogenetic analysis.</li>
	<li>For teratoma formation, inject an undifferentiated TIL-derived iPSC (1 x 106) suspension in 100 &#181;l of DMEM containing 10% FCS into the subcutaneous tissue of 6-8 week old female NOD/SCID mice. Stain teratoma sections with hematoxylin and eosin.</li>
</ol>
4. Immunofluorescence Staining of iPSCs for SSEA3, SSEA4, TRA1-60 and TRA1-81
<ol>
	<li>Wash iPSCs with 1 ml of PBS and fix the iPSCs with 1 ml of 4% paraformaldehyde solution for 10 min. Remove the 4% paraformaldehyde solution and wash the iPSCs with 1 ml of PBS 3 times. 
	NOTE: Be careful when using paraformaldehyde because it is toxic.</li>
	<li>Pretreat the iPSCs with blocking buffer (Table 1) for 30 min. Meanwhile, dilute the primary antibodies (rat anti-human SSEA3, mouse anti-human SSEA4, mouse anti-human TRA1-60, and mouse anti-human TRA1-81) 1:50 in 1.5% goat serum solution diluted with PBS and TritonX-100 (total volume: 1 ml).</li>
	<li>Remove the blocking buffer (Table 1). Add the diluted primary antibody solution and incubate for 1 hr at room temperature. Meanwhile, dilute the secondary antibody (anti-mouse IgG and IgM or anti-rat IgM) 1:50 in 1.5% goat serum solution.</li>
	<li>Remove the diluted primary antibody solution and wash the iPSCs with 1 ml PBS 3 times, each for 5 min. Add the diluted secondary antibody solution and incubate for 45 min at room temperature in a dark room.</li>
	<li>Remove the diluted secondary antibody solution and wash the iPSCs with 1 ml of PBS 3 times, each for 5 min. Observe the iPSCs with immunofluorescence microscopy.</li>
</ol>
5. Immunofluorescence Staining of iPSCs for Oct3/4
<ol>
	<li>Wash iPSCs with 1 ml of PBS and fix the iPSCs with 1 ml of 4% paraformaldehyde solution for 10 min. Remove the 4% paraformaldehyde solution and wash the iPSCs with PBS 3 times.</li>
	<li>Add permeabilization buffer (Table 1) and incubate at room temperature for 10 min. Remove the permeabilization buffer and add blocking buffer (Table 1).</li>
	<li>Incubate at room temperature for 30 min. Meanwhile, dilute the primary antibody (mouse anti-human Oct3/4) 1:50 in blocking buffer.</li>
	<li>Add the diluted primary antibody solution and incubate at 4 &#176;C overnight.</li>
	<li>Remove the diluted primary antibody solution and wash the iPSCs with 1ml of PBS 3 times, each for 5 min. Meanwhile, dilute the secondary antibody (goat anti-mouse IgG/IgM) 1:100 in blocking buffer.</li>
	<li>Add the diluted secondary antibody solution and incubate at room temperature in a dark room for 45 min.</li>
	<li>Remove the diluted secondary solution and wash the iPSCs with 1 ml of PBS 3 times, each for 5 min. Observe the iPSCs under immunofluorescence microscopy.</li>
</ol>

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The authors declare that they have no competing financial interests.

Here, we demonstrated a protocol for reprogramming melanoma TILs to iPSCs by SeV-mediated transduction of the four transcription factors OCT3/4, SOX2, KLF4, and c-MYC. This approach, using a SeV system to reprogram T cells, offers the advantage of a non-integrating method7.
A previous study showed that a SeV reprogramming system was highly efficient and reliable to reprogram not only fibroblasts but also peripheral blood T cells7,17. In addition, we have recently shown th...

Cellular reprogramming technology that allows generation of induced pluripotent stem cells (iPSCs) via overexpression of a defined set of transcription factors holds great promise in the field of cell-based therapies1,2. These iPSCs exhibit transcriptional and epigenetic features and have the capacity for self-renewal and pluripotency, similarly to embryonic stem cells (ESCs)3-5. Remarkable progress made in reprogramming technology over the past decade has allowed us to generate human iPSCs even from terminally differentiated cells, such as T cells6-8. T cell-derived iPSCs (TiPSCs) retain the same rearranged configuration of T cell receptor (TCR) chain genes as the original T cells, which allows regeneration of antigen-specific T cells from TiPSCs9-11.
Nearly 80% of melanoma-infiltrating lymphocytes (TILs) obtained from a patient&#39;s tumor specifically recognize tumor-associated antigens and maintain cytotoxicity against the original cancer cells12. Notably, the expression of programmed cell death protein-1 (PD-1) on TILs was found to identify the autologous tumor-reactive repertoire, including mutated neoantigen-specific CD8+ lymphocytes13. Adoptive transfer of ex-vivo expanded autologous TILs in combination with preparative lymphodepleting regimens and systemic administration of Interleukin-2 (IL-2) can cause substantial regression of metastatic melanoma in subsets of patients14. Despite encouraging results in preclinical models and in patients, poor survival of infused T cells and the existence of immune suppressive pathways appear to compromise the full potential of adoptive T cell therapy. Current clinical protocols require extensive ex vivo manipulation of autologous T cells in order to obtain large numbers. This results in the generation of terminally differentiated T cells that have poor survival, reduced proliferative capacity, and high levels of PD-115.
This limitation of adoptive T cell therapy can be theoretically overcome by using iPSCs that can provide an unlimited source of autologous T cells for immunotherapy. We have recently reported the reprogramming of melanoma TILs expressing high levels of PD-1 by Sendai virus (SeV)-mediated transduction of the four transcription factors, OCT3/4, SOX2, KLF4, and c-MYC16. While retrovirus vectors require integration into host chromosomes to express reprogramming genes, SeV vectors are non-integrating and are eventually eliminated from the cytoplasm. Reprogramming efficiency is much higher with a SeV system compared with lentivirus or retrovirus vectors6-8. Furthermore, SeV can specifically reprogram T cells in peripheral blood mononuclear cells (PBMCs), while some iPSC clones generated by lentivirus or retrovirus vectors can be from nonlymphoid lineages6-8. Here, we detail the procedures implemented for the isolation and activation of human melanoma TILs and for the generation of TIL-derived iPSCs using a SeV reprogramming system.

<table><tbody><tr><td>gentle MACS C Tubes</td><td>Miltenyi Biotec</td><td>130-093-237</td><td></td></tr><tr><td>gentle MACS Dissociator</td><td>Miltenyi Biotec</td><td>130-093-235</td><td></td></tr><tr><td>Tumor Dissociation Kit, human</td><td>Miltenyi Biotec</td><td>130-095-929</td><td></td></tr><tr><td>RPMI 1640</td><td>Life technologies</td><td>11875-093</td><td></td></tr><tr><td>Falcon 70 um Cell Strainer</td><td>BD</td><td>352350</td><td></td></tr><tr><td>BD Falcon 50ml Conical Cntrifuge tubes</td><td>BD</td><td>352070</td><td></td></tr><tr><td>IMDM</td><td>Life technologies</td><td>12440053</td><td></td></tr><tr><td>human AB serum</td><td>Life technologies</td><td>34005100</td><td></td></tr><tr><td>L-glutamine (200mM)</td><td>Life technologies</td><td>25030-081</td><td></td></tr><tr><td>2-mercaptoethanol (1000x, 55mM)</td><td>Life technologies</td><td>21985-023</td><td></td></tr><tr><td>Penicillin-Streptomycin&amp;nbsp;</td><td>Life technologies</td><td>15140-122</td><td></td></tr><tr><td>gentamicin</td><td>Life technologies</td><td>15750-060</td><td></td></tr><tr><td>Ficoll-Paque PLUS</td><td>GE</td><td>17-1440-02</td><td></td></tr><tr><td>D-PBS (-)</td><td>Life technologies</td><td>14040-133</td><td></td></tr><tr><td>recombinant human (rh) IL-2</td><td>Aldesleukin, Prometheus Laboratories Inc.</td><td></td><td></td></tr><tr><td>Purified NA/LE Mouse Anti-Human CD3</td><td>BD</td><td>555329</td><td></td></tr><tr><td>Purified NA/LE Mouse Anti-Human CD28</td><td>BD</td><td>555725</td><td></td></tr><tr><td>X-VIVO 15</td><td>Lonza</td><td>04-418Q</td><td></td></tr><tr><td>FBS</td><td>Gibco</td><td>26140-079</td><td></td></tr><tr><td>HEPES</td><td>Life technologies</td><td>15630-080</td><td></td></tr><tr><td>N-Acetylcysteine</td><td>Cumberland Pharmaceuticals Inc.</td><td>NDC 66220-207-30</td><td></td></tr><tr><td>Falcon Tissue Culture Plates (6-well)</td><td>Corning</td><td>353046</td><td></td></tr><tr><td>Falcon Tissue Culture Plates (24-well)</td><td>Corning</td><td>353047</td><td></td></tr><tr><td>Sendai virus vector</td><td>DNAVEC</td><td></td><td></td></tr><tr><td>SNL feeder cells</td><td>Cell Biolabs, Inc</td><td>CBA-316</td><td></td></tr><tr><td>mitomycin C</td><td>SIGMA</td><td>M4287</td><td>soluble in water (0.5 mg/ml)</td></tr><tr><td>gelatin</td><td>SIGMA</td><td>G1890</td><td></td></tr><tr><td>basic fibroblast growth factor (bFGF)</td><td>Life technologies</td><td>PHG0264</td><td></td></tr></tbody></table>

generation of induced pluripotent stem cells from human melanoma tumor-infiltrating lymphocytes

Adoptive transfer of ex vivo expanded autologous tumor-infiltrating lymphocytes (TILs) can mediate durable and complete responses in significant subsets of patients with metastatic melanoma. Major obstacles of this approach are the reduced viability of transferred T cells, caused by telomere shortening, and the limited number of TILs obtained from patients. Less-differentiated T cells with long telomeres would be an ideal T cell subset for adoptive T cell therapy;however, generating large numbers of these less-differentiated T cells is problematic. This limitation of adoptive T cell therapy can be theoretically overcome by using induced pluripotent stem cells (iPSCs) that self-renew, maintain pluripotency, have elongated telomeres, and provide an unlimited source of autologous T cells for immunotherapy. Here, we present a protocol to generate iPSCs using Sendai virus vectors for the transduction of reprogramming factors into TILs. This protocol generates fully reprogrammed, vector-free clones. These TIL-derived iPSCs might be able to generate less-differentiated patient- and tumor-specific T cells for adoptive T cell therapy.

Figure 1 shows the overview of the procedure that involves the initial expansion of melanoma TILs with rhIL-2, which is followed by activation with anti-CD3/CD28 and gene transfer of OCT3/4, KLF4, SOX2, and c-MYC to TILs for the generation of iPSCs. Usually, TILs on culture with rhIL-2 start to form spheres 21-28 days after initiation of culture. At this point, TILs are ready to be activated with anti-CD3/CD28. Figure 2A shows TILs, on culture with rhIL-2...

Watch this Scientific Journal Video about Generation of Induced Pluripotent Stem Cells from Human Melanoma Tumor-infiltrating Lymphocytes at JoVE.com

Generation of Induced Pluripotent Stem Cells from Human Melanoma Tumor-infiltrating Lymphocytes

The goal of this protocol is to show the protocol for reprogramming melanoma tumor-infiltrating lymphocytes into induced pluripotent stem cells.

Adoptive transfer of ex vivo expanded autologous tumor-infiltrating lymphocytes (TILs) can mediate durable and complete responses in significant subsets ...

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9.8K Views.  University of Michigan. The goal of this protocol is to show the protocol for reprogramming melanoma tumor-infiltrating lymphocytes into induced pluripotent stem cells.

Video: Generation of Induced Pluripotent Stem Cells from Human Melanoma Tumor-infiltrating Lymphocytes

Generation of Integration-free Human Induced Pluripotent Stem Cells Using Hair-derived Keratinocytes

Recent advances in reprogramming allow us to turn somatic cells into human induced pluripotent stem cells (hiPSCs). Disease modeling using patient-specific hiPSCs allows the study of the underlying mechanism for pathogenesis, also providing a platform for the development of in vitro drug screening and gene therapy to improve treatment options. The promising potential of hiPSCs for regenerative medicine is also evident from the increasing number of publications (>7000) on iPSCs in recent years. Various cell types from distinct lineages have been successfully used for hiPSC generation, including skin fibroblasts, hematopoietic cells and epidermal keratinocytes. While skin biopsies and blood collection are routinely performed in many labs as a source of somatic cells for the generation of hiPSCs, the collection and subsequent derivation of hair keratinocytes are less commonly used. Hair-derived keratinocytes represent a non-invasive approach to obtain cell samples from patients. Here we outline a simple non-invasive method for the derivation of keratinocytes from plucked hair. We also provide instructions for maintenance of keratinocytes and subsequent reprogramming to generate integration-free hiPSC using episomal vectors.

This manuscript provides a step-by-step procedure for the derivation and maintenance of human keratinocytes from plucked hair and subsequent generation of integration-free human induced pluripotent stem cells (hiPSCs) by episomal vectors.

Recent advances in reprogramming allow us to turn somatic cells into human induced pluripotent stem cells (hiPSCs). Disease modeling using ...

Feeder-free Derivation of Melanocytes from Human Pluripotent Stem Cells

Human pluripotent stem cells (hPSCs) represent a platform to study human development in vitro under both normal and disease conditions. Researchers can direct the differentiation of hPSCs into the cell type of interest by manipulating the culture conditions to recapitulate signals seen during development. One such cell type is the melanocyte, a pigment-producing cell of neural crest (NC) origin responsible for protecting the skin against UV irradiation. This protocol presents an extension of a currently available in vitro Neural Crest differentiation protocol from hPSCs to further differentiate NC into fully pigmented melanocytes. Melanocyte precursors can be enriched from the Neural Crest protocol via a timed exposure to activators of WNT, BMP, and EDN3 signaling under dual-SMAD-inhibition conditions. The resultant melanocyte precursors are then purified and matured into fully pigmented melanocytes by culture in a selective medium. The resultant melanocytes are fully pigmented and stain appropriately for proteins characteristic of mature melanocytes.

This work describes an in vitro differentiation protocol to produce pigmented, mature melanocytes from human pluripotent stem cells via a neural crest and melanoblast intermediate stage using a feeder-free, 25 day protocol.

Human pluripotent stem cells (hPSCs) represent a platform to study human development in vitro under both normal and disease conditions. Researchers can ...

A Three-dimensional Thymic Culture System to Generate Murine Induced Pluripotent Stem Cell-derived Tumor Antigen-specific Thymic Emigrants

The inheritance of pre-rearranged T cell receptors (TCRs) and their epigenetic rejuvenation make induced pluripotent stem cell (iPSC)-derived T cells a promising source for adoptive T cell therapy (ACT). However, classical in vitro methods for producing regenerated T cells from iPSC result in either innate-like or terminally differentiated T cells, which are phenotypically and functionally distinct from na&#239;ve T cells. Recently, a novel three-dimensional (3D) thymic culture system was developed to generate a homogenous subset of CD8&#945;&#946;+ antigen-specific T cells with a na&#239;ve T cell-like functional phenotype, including the capacity for proliferation, memory formation, and tumor suppression in vivo. This protocol avoids aberrant developmental fates, allowing for the generation of clinically relevant iPSC-derived T cells, designated as iPSC-derived thymic emigrants (iTE), while also providing a potent tool to elucidate the subsequent functions necessary for T cell maturation after thymic selection.

This article describes a novel method to generate tumor antigen-specific induced pluripotent stem cell-derived thymic emigrants (iTE) by a three-dimensional (3D) thymic culture system. iTE are a homogenous subset of T cells closely related to na&#239;ve T cells with the capacity for proliferation, memory formation, and tumor suppression.

The inheritance of pre-rearranged T cell receptors (TCRs) and their epigenetic rejuvenation make induced pluripotent stem cell (iPSC)-derived T cells a ...

Cancer Research

Directed Differentiation of Induced Pluripotent Stem Cells towards T Lymphocytes

Adoptive cell transfer (ACT) of antigen-specific CD8+ cytotoxic T lymphocytes (CTLs) is a promising treatment for a variety of malignancies 1. CTLs can recognize malignant cells by interacting tumor antigens with the T cell receptors (TCR), and release cytotoxins as well as cytokines to kill malignant cells. It is known that less-differentiated and central-memory-like (termed highly reactive) CTLs are the optimal population for ACT-based immunotherapy, because these CTLs have a high proliferative potential, are less prone to apoptosis than more differentiated cells and have a higher ability to respond to homeostatic cytokines 2-7. However, due to difficulties in obtaining a high number of such CTLs from patients, there is an urgent need to find a new approach to generate highly reactive Ag-specific CTLs for successful ACT-based therapies.
TCR transduction of the self-renewable stem cells for immune reconstitution has a therapeutic potential for the treatment of diseases 8-10. However, the approach to obtain embryonic stem cells (ESCs) from patients is not feasible. Although the use of hematopoietic stem cells (HSCs) for therapeutic purposes has been widely applied in clinic 11-13, HSCs have reduced differentiation and proliferative capacities, and HSCs are difficult to expand in in vitro cell culture 14-16. Recent iPS cell technology and the development of an in vitro system for gene delivery are capable of generating iPS cells from patients without any surgical approach. In addition, like ESCs, iPS cells possess indefinite proliferative capacity in vitro, and have been shown to differentiate into hematopoietic cells. Thus, iPS cells have greater potential to be used in ACT-based immunotherapy compared to ESCs or HSCs.
Here, we present methods for the generation of T lymphocytes from iPS cells in vitro, and in vivo programming of antigen-specific CTLs from iPS cells for promoting cancer immune surveillance. Stimulation in vitro with a Notch ligand drives T cell differentiation from iPS cells, and TCR gene transduction results in iPS cells differentiating into antigen-specific T cells in vivo, which prevents tumor growth. Thus, we demonstrate antigen-specific T cell differentiation from iPS cells. Our studies provide a potentially more efficient approach for generating antigen-specific CTLs for ACT-based therapies and facilitate the development of therapeutic strategies for diseases.

Generation of T lymphocytes from induced pluripotent stem (iPS) cells gives an alternative approach of using embryonic stem cells for T cell-based immunotherapy. The method shows that by utilizing either in vitro or in vivo induction system, iPS cells are able to differentiate into both conventional and antigen-specific T lymphocytes.

Adoptive cell transfer (ACT) of antigen-specific CD8+  cytotoxic T lymphocytes (CTLs) is a promising treatment for a variety of  malignancies 1. CTLs can  ...

Immunology and Infection

Using Human Induced Pluripotent Stem Cells for the Generation of Tumor Antigen-specific T Cells

The generation and expansion of functional T cells in vitro can lead to a broad range of clinical applications. One such use is for the treatment of patients with advanced cancer. Adoptive T cell transfer (ACT) of highly enriched tumor antigen-specific T cells has been shown to cause durable regression of metastatic cancer in some patients. However, during expansion, these cells may become exhausted or senescent, limiting their effector function and persistence in vivo. Induced pluripotent stem cell (iPSC) technology may overcome these obstacles by leading to in vitro generation of large numbers of less differentiated tumor antigen-specific T cells. Human iPSC (hiPSC) have the capacity to differentiate into any type of somatic cell, including lymphocytes, which retain the original T cell receptor (TCR) genomic rearrangement when a T cell is used as a starting cell. Therefore, reprogramming of human tumor antigen-specific T cells to hiPSC followed by redifferentiation to T cell lineage has the potential to produce rejuvenated tumor antigen-specific T cells. Described here is a method for generating tumor antigen-specific CD8&#945;&#946;+ single positive (SP) T cells from hiPSC using OP9/DLL1 co-culture system. This method is a powerful tool for in vitro T cell lineage generation and will facilitate the development of in vitro derived T cells for use in regenerative medicine and cell-based therapies.

This article describes a method to generate functional tumor antigen-specific induced pluripotent stem cell-derived CD8&#945;&#946;+ single positive T cells using OP9/DLL1 co-culture system.

The generation and expansion of functional T cells in vitro can lead to a broad range of clinical applications. One such use is for the treatment of ...

Patient Derived Cell Culture and Isolation of CD133+ Putative Cancer Stem Cells from Melanoma

Despite improved treatments options for melanoma available today, patients with advanced malignant melanoma still have a poor prognosis for progression-free and overall survival. Therefore, translational research needs to provide further molecular evidence to improve targeted therapies for malignant melanomas. In the past, oncogenic mechanisms related to melanoma were extensively studied in established cell lines. On the way to more personalized treatment regimens based on individual genetic profiles, we propose to use patient-derived cell lines instead of generic cell lines. Together with high quality clinical data, especially on patient follow-up, these cells will be instrumental to better understand the molecular mechanisms behind melanoma progression.
Here, we report the establishment of primary melanoma cultures from dissected fresh tumor tissue. This procedure includes mincing and dissociation of the tissue into single cells, removal of contaminations with erythrocytes and fibroblasts as well as primary culture and reliable verification of the cells' melanoma origin.
Recent reports revealed that melanomas, like the majority of tumors, harbor a small subpopulation of cancer stem cells (CSCs), which seem to exclusively fuel tumor initiation and progression towards the metastatic state. One of the key markers for CSC identification and isolation in melanoma is CD133. To isolate CD133+ CSCs from primary melanoma cultures, we have modified and optimized the Magnetic-Activated Cell Sorting (MACS) procedure from Miltenyi resulting in high sorting purity and viability of CD133+ CSCs and CD133- bulk, which can be cultivated and functionally analyzed thereafter.

Patient Derived Cell Culture and Isolation of CD133+ Putative Cancer Stem Cells from Melanoma

This article describes the preparation of freshly obtained melanoma tissue into primary cell cultures, and how to remove contaminations of erythrocytes and fibroblasts from the tumor cells. Finally, we describe how CD133+ putative melanoma stem cells are sorted from the CD133- bulk using Magnetic Activated Cell Sorting (MACS).

Despite improved treatments options for melanoma available today, patients with advanced malignant melanoma still have a poor prognosis for ...

Medicine

Direct Reprogramming of Mouse Fibroblasts into Melanocytes

The loss of function of melanocytes leads to vitiligo, which seriously affects the physical and mental health of the affected individuals. Presently, there is no effective long-term treatment for vitiligo. Therefore, it is imperative to develop a convenient and effective treatment for vitiligo. Regenerative medicine technology for direct reprogramming of skin cells into melanocytes seems to be a promising novel treatment of vitiligo. This involves the direct reprogramming of the patient's skin cells into functional melanocytes to help ameliorate the loss of melanocytes in patients with vitiligo. However, this method needs to be first tested on mice. Although direct reprogramming is widely used, there is no clear protocol for direct reprogramming into melanocytes. Moreover, the number of available transcription factors is overwhelming. 
Here, a concentrated lentivirus packaging system protocol is presented to produce transcription factors selected for reprogramming skin cells to melanocytes, including Sox10, Mitf, Pax3, Sox2, Sox9, and Snai2. Mouse embryonic fibroblasts (MEFs) were infected with the concentrated lentivirus for all these transcription factors for the direct reprogramming of the MEFs into induced melanocytes (iMels) in vitro. Furthermore, these transcription factors were screened, and the system was optimized for direct reprogramming to melanocytes. The expression of the characteristic markers of melanin in iMels at the gene or protein level was significantly increased. These results suggest that direct reprogramming of fibroblasts to melanocytes could be a successful new therapeutic strategy for vitiligo and confirm the mechanism of melanocyte development, which will provide the basis for further direct reprogramming of fibroblasts into melanocytes in vivo.

Here, we describe an optimized direct reprogramming system for melanocytes and a high-efficiency, concentrated virus packaging system that ensures smooth direct reprogramming.

The loss of function of melanocytes leads to vitiligo, which seriously affects the physical and mental health of the affected individuals. Presently, ...

Patient-Derived Melanoma Organoids: A Frontier in Cancer Immunotherapy

Unveiling Therapeutic Opportunities with Melanoma Patient-derived Organoid Models

With the development of immunotherapy, there is an ongoing need to develop models that can recapitulate the tumor microenvironment of native tumors. While traditional two- and three-dimensional models can offer insights into cancer development and progression, these lack crucial aspects that hinder a faithful mimic of native tumors. An alternative model that has gained a lot of attention is the patient-derived organoid. The development of these organoids recapitulates the complex intercellular communication, tumor microenvironment, and histoarchitecture of tumors. This paper describes the protocol for establishing melanoma patient-derived organoid (MPDO) models. To validate these models, we assessed the immune cell composition, including the expression levels of T-cell activation markers, to confirm the cellular heterogeneity of the organoids. Additionally, to describe the potential utility of MPDOs in cellular therapies, we evaluated the cytotoxic capabilities of treating the organoids with &#947;&#948; T-cells. In conclusion, the MPDO models offer promising avenues for understanding tumor complexity, validating therapeutic strategies, and potentially advancing personalized treatment.

Author Spotlight: Recreating Melanoma Complexity with Patient-Derived Organoids for Immunotherapy Evaluation

Here, we present a protocol to generate melanoma patient-derived organoids by culturing disassociated cell suspensions from fresh melanoma tissues. These organoids faithfully recapitulate patient-specific tumors in vitro, offering an innovative approach to exploring tumor immunosuppressive mechanisms, drug screening, drug resistance mechanisms, and cancer surveillance approaches.

With the development of immunotherapy, there is an ongoing need to develop models that can recapitulate the tumor microenvironment of native tumors. While ...

Stem Cell-Derived Viral Ag-Specific T Lymphocytes Suppress HBV Replication in Mice

Hepatitis B virus (HBV) infection is a global health issue. With over 350 million people affected worldwide, HBV infection remains the leading cause of liver cancer. This is a major concern, especially in developing countries. Failure of the immune system to mount an effective response against HBV leads to chronic infection. Although HBV vaccine is present and novel antiviral medicines are being created, eradication of virus-reservoir cells remains a major health topic. Described here is a method for the generation of viral antigen (Ag) -specific CD8+ cytotoxic T lymphocytes (CTLs) derived from induced pluripotent stem cells (iPSCs) (i.e., iPSC-CTLs), which have the ability to suppress HBV replication. HBV replication is efficiently induced in mice through hydrodynamic injection of an HBV expression plasmid, pAAV/HBV1.2, into the liver. Then, HBV surface Ag-specific mouse iPSC-CTLs are adoptively transferred, which greatly suppresses HBV replication in the liver and blood as well as prevents HBV surface Ag expression in hepatocytes. This method demonstrates HBV replication in mice after hydrodynamic injection and that stem cell-derived viral Ag-specific CTLs can suppress HBV replication. This protocol provides a useful method for HBV immunotherapy.

Presented here is a protocol for the effective suppression of hepatitis B virus (HBV) replication in mice by utilizing adoptive cell transfer (ACT) of stem cell-derived viral antigen (Ag)-specific T lymphocytes. This procedure may be adapted for potential ACT-based immunotherapy of HBV infection.

Hepatitis B virus (HBV) infection is a global health issue. With over 350 million people affected worldwide, HBV infection remains the leading cause of ...

Generation of Human Induced Pluripotent Stem Cells from Peripheral Blood Using the STEMCCA Lentiviral Vector

Through the ectopic expression of four transcription factors, Oct4, Klf4, Sox2 and cMyc, human somatic cells can be converted to a pluripotent state, generating so-called induced pluripotent stem cells (iPSCs)1-4. Patient-specific iPSCs lack the ethical concerns that surround embryonic stem cells (ESCs) and would bypass possible immune rejection. Thus, iPSCs have attracted considerable attention for disease modeling studies, the screening of pharmacological compounds, and regenerative therapies5.
We have shown the generation of transgene-free human iPSCs from patients with different lung diseases using a single excisable polycistronic lentiviral Stem Cell Cassette (STEMCCA) encoding the Yamanaka factors6. These iPSC lines were generated from skin fibroblasts, the most common cell type used for reprogramming. Normally, obtaining fibroblasts requires a skin punch biopsy followed by expansion of the cells in culture for a few passages. Importantly, a number of groups have reported the reprogramming of human peripheral blood cells into iPSCs7-9. In one study, a Tet inducible version of the STEMCCA vector was employed9, which required the blood cells to be simultaneously infected with a constitutively active lentivirus encoding the reverse tetracycline transactivator. In contrast to fibroblasts, peripheral blood cells can be collected via minimally invasive procedures, greatly reducing the discomfort and distress of the patient. A simple and effective protocol for reprogramming blood cells using a constitutive single excisable vector may accelerate the application of iPSC technology by making it accessible to a broader research community. Furthermore, reprogramming of peripheral blood cells allows for the generation of iPSCs from individuals in which skin biopsies should be avoided (i.e. aberrant scarring) or due to pre-existing disease conditions preventing access to punch biopsies.
Here we demonstrate a protocol for the generation of human iPSCs from peripheral blood mononuclear cells (PBMCs) using a single floxed-excisable lentiviral vector constitutively expressing the 4 factors. Freshly collected or thawed PBMCs are expanded for 9 days as described10,11 in medium containing ascorbic acid, SCF, IGF-1, IL-3 and EPO before being transduced with the STEMCCA lentivirus. Cells are then plated onto MEFs and ESC-like colonies can be visualized two weeks after infection. Finally, selected clones are expanded and tested for the expression of the pluripotency markers SSEA-4, Tra-1-60 and Tra-1-81. This protocol is simple, robust and highly consistent, providing a reliable methodology for the generation of human iPSCs from readily accessible 4 ml of blood.

Here we show a simple and effective protocol for the generation of human iPSCs from 3-4 ml of peripheral blood using a single lentiviral reprogramming vector. Reprogramming of readily available blood cells promises to accelerate the utilization of iPSC technology by making it accessible to a broader research community.

Through the ectopic expression of four transcription factors, Oct4, Klf4, Sox2 and cMyc, human somatic cells can be converted to a pluripotent state, ...

Generation of Induced Pluripotent Stem Cells from Human Melanoma Tumor-infiltrating Lymphocytes

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