Review: Gene-Modified Dendritic Cells for Use in Tumor Vaccines

Dendritic cells (DCs) are potent antigen-presenting cells capable of priming activation of naive T cells. Because of their immunostimulatory capacity, immunization with DCs presenting tumor antigens has been proposed as a treatment regimen for cancer. The results from translational research studies and early clinical trials point to the need for improvement of DC-based tumor vaccines before they become a more broadly applicable treatment modality. In this regard, studies suggest that genetic modification of DCs to express tumor antigens and/or immunomodulatory proteins may improve their capacity to promote an antitumor response. Because the DC phenotype is relatively unstable, nonperturbing methods of gene transfer must be employed that do not compromise viability or immunostimulatory capacity. DCs expressing transgenes encoding tumor antigens have been shown to be more potent primers of antitumor immunity both in vitro and in animal models of disease; in some measures of immune priming, gene-modified DCs exceeded their soluble antigen-pulsed counterparts. Cytokine gene modification of DCs has improved their capacity to prime tumor antigenspecific T cell responses and promote antitumor immunity in vivo. Here, we review the current status of genemodified DCs in both human and murine studies. Although successful results have been obtained to date in experimental systems, we discuss potential problems that have already arisen and may yet be encountered before gene-modified DCs are more widely applicable for use in human clinical trials.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63168/1/10430340050015419.pd

On combining antineoplastic drugs with tumor vaccines

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46863/1/262_2003_Article_426.pd

A Rapid and Quantitative Assay to Estimate Gene Transfer into Retrovirally Transduced Hematopoietic Stem/Progenitor Cells Using a 96-Well Format PCR and Fluorescent Detection System Universal for MMLV-Based Proviruses

Overview summary The polymerase chain reaction (PCR) analysis of colonies of clonogenic cells growing in methylcellulose medium is a routine procedure to estimate the frequency of retroviral transduction into hematopoietic stem/progenitor cells. This study describes a sensitive assay system that takes advantage of the standard 96-well format to expedite the processing of single methylcellulose colonies. Assay sensitivity is dependent on a PCR primer pair which amplifies a region of the ψ packaging sequence of all Moloney-based retroviruses tested. Using this primer pair, we present the optimized PCR conditions for the analysis of single colonies of clonogenic cells growing in methylcellulose medium as well as the conditions for a semiquantitative bulk PCR assay to estimate the transduction frequency immediately following the transduction protocol. This PCR primer pair, along with the capability for more rapid screening of hematopoietic stem/progenitor colonies, is especially useful for the laboratory that is screening a number of different retroviral constructions for their transduction efficiency.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63170/1/hum.1996.7.3-343.pd

Tumor-Associated Tertiary Lymphoid Structures: Gene-Expression Profiling and Their Bioengineering

Tertiary lymphoid structures (TLSs) have been identified in the parenchyma and/or in the peripheral margins of human solid tumors. Uncovering the functional nature of these structures is the subject of much intensive investigation. Studies have shown a direct correlation of the presence of human tumor-localized TLS and better patient outcome (e.g., increase in overall survival) in certain solid tumor histologies, but not all. We had identified a tumor-derived immune gene-expression signature, encoding 12 distinct chemokines, which could reliably identify the presence of TLSs, of different degrees, in various human solid tumors. We are focused on understanding the influence of TLSs on the tumor microenvironment and leveraging this understanding to both manipulate the antitumor immune response and potentially enhance immunotherapy applications. Moreover, as not all human solid tumors show the presence of these lymphoid structures, we are embarking on bioengineering approaches to design and build “designer” TLSs to address, and potentially overcome, an unmet medical need in cancer patients whose tumors lack such lymphoid structures

Induction of Tertiary Lymphoid Structures With Antitumor Function by a Lymph Node-Derived Stromal Cell Line

Tertiary lymphoid structures (TLSs) associate with better prognosis in certain cancer types, but their underlying formation and immunological benefit remain to be determined. We established a mouse model of TLSs to study their contribution to antitumor immunity. Because the stroma in lymph nodes (sLN) participates in architectural support, lymphogenesis, and lymphocyte recruitment, we hypothesized that TLSs can be created by sLN. We selected a sLN line with fibroblast morphology that expressed sLN surface markers and lymphoid chemokines. The subcutaneous injection of the sLN line successfully induced TLSs that attracted infiltration of host immune cell subsets. Injection of MC38 tumor lysate-pulsed dendritic cells activated TLS-residing lymphocytes to demonstrate specific cytotoxicity. The presence of TLSs suppressed MC38 tumor growth in vivo by improving antitumor activity of tumor-infiltrating lymphocytes with downregulated immune checkpoint proteins (PD-1 and Tim-3). Future engineering of sLN lines may allow for further enhancements of TLS functions and immune cell compositions

RANTES Secretion by Gene-Modified Tumor Cells Results in Loss of Tumorigenicity In Vivo: Role of Immune Cell Subpopulations

Overview summary Members of the chemokine superfamily mediate potent and selective chemoattraction of a variety of immune cell subsets, which is concentration dependent. This important and novel biologic activity raises the possibility of using chemokines as adjuvants in cancer vaccine strategies. We describe here the in vitro chemotactic capacity of RANTES for murine CD8+ tumor-infiltrating lymphocytes (TIL). Moreover, murine fibrosarcoma cells transfected with the cDNA encoding RANTES and secreting high levels of this chemokine become nontumorigenic in immunocompetent mice. The antitumor effect of RANTES is dependent on inherent tumor immunogenicity and is mediated through the participation of host-derived T cells and macrophages. Thus, the general chemoattractant properties exhibited by RANTES in vitro appear to be relevant in an in vivo model. These data warrant further investigation of other distinct members of the chemokine superfamily for their potential use, either alone or in combination, in gene therapy approaches that employ tumor cells as immunogens.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63285/1/hum.1996.7.13-1545.pd

Design and Function of a Dendrimer-Based Therapeutic Nanodevice Targeted to Tumor Cells Through the Folate Receptor

Purpose . We sought to develop nanoscale drug delivery materials that would allow targeted intracellular delivery while having an imaging capability for tracking uptake of the material. A complex nanodevice was designed and synthesized that targets tumor cells through the folate receptor.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41493/1/11095_2004_Article_378868.pd

The emergence of team resilience: A multilevel conceptual model of facilitating factors

With empirical research on team resilience on the rise, there is a need for an integrative conceptual model that delineates the essential elements of this concept and offers a heuristic for the integration of findings across studies. To address this need, we propose a multilevel model of team resilience that originates in the resources of individual team members and emerges as a team-level construct through dynamic person–situation interactions that are triggered by adverse events. In so doing, we define team resilience as an emergent outcome characterized by the trajectory of a team's functioning, following adversity exposure, as one that is largely unaffected or returns to normal levels after some degree of deterioration in functioning. This conceptual model offers a departure point for future work on team resilience and reinforces the need to incorporate inputs and process mechanisms inherent within dynamic interactions among individual members of a team. Of particular, importance is the examination of these inputs, process mechanisms and emergent states, and outcomes over time, and in the context of task demands, objectives, and adverse events. Practitioner points: Team resilience as a dynamic, multilevel phenomenon requires clarity on the individual- and team-level factors that foster its emergence within occupational and organizational settings. An understanding of the nature (e.g., timing, chronicity) of adverse events is key to studying and intervening to foster team resilience within occupational and organizational settings

Induction of anti-tumor immunity by vaccination with dendritic cells pulsed with anti-CD44 IgG opsonized tumor cells

Due to the pivotal role that dendritic cells (DC) play in eliciting and maintaining functional anti-tumor T cell responses, these APC have been exploited against tumors. DC express several receptors for the Fc portion of IgG (Fcγ receptors) that mediate the internalization of antigen-IgG complexes and promote efficient MHC class I and II restricted antigen presentation. In this study, the efficacy of vaccination with DC pulsed with apoptotic B16 melanoma cells opsonized with an anti-CD44 IgG (B16-CD44) was explored. Immature bone marrow derived DC grown in vitro with IL-4 and GM-CSF were pulsed with B16-CD44. After 48 h of pulsing, maturation of DC was demonstrated by production of IL-12 and upregulation of CD80 and CD40 expression. To test the efficacy of vaccination with DC+B16-CD44, mice were vaccinated subcutaneously Lymphocytes from mice vaccinated with DC+B16-CD44 produced IFN-γ in response to B16 melanoma lysates as well as an MHC class I restricted B16 melanoma-associated peptide, indicating B16 specific CD8 T cell activation. Upon challenge with viable B16 cells, all mice vaccinated with DC alone developed tumor compared to 40% of mice vaccinated with DC+B16-CD44; 60% of the latter mice remained tumor free for at least 8 months. In addition, established lung tumors and distant metastases were significantly reduced in mice treated with DC+B16-CD44. Lastly, delayed growth of established subcutaneous tumors was induced by combination therapy with anti-CD44 antibodies followed by DC injection. This study demonstrates the efficacy of targeting tumor antigens to DC via Fcγ receptors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45862/1/262_2005_Article_104.pd