Density Of Antigen-presenting Cells Research Articles

Comparative analysis of antigen-presenting cells in gingival tissues in healthy and periodontitis patients

AimsMicrobial flora of dental plaque trigger innate and adaptive immune responses. The function of antigen-presenting cells (APCs) is to bridge the innate and adaptive immune systems. The human immune system...

A transcriptome-informed QSP model of metastatic triple-negative breast cancer identifies predictive biomarkers for PD-1 inhibition.

Triple-negative breast cancer (TNBC), a highly metastatic breast cancer subtype, has limited treatment options. While a small number of patients attain clinical benefit with single-agent checkpoint inhibitors, identifying these patients before the therapy remains challenging. Here, we developed a transcriptome-informed quantitative systems pharmacology model of metastatic TNBC by integrating heterogenous metastatic tumors. In silico clinical trial with an anti-PD-1 drug, pembrolizumab, predicted that several features, such as the density of antigen-presenting cells, the fraction of cytotoxic T cells in lymph nodes, and the richness of cancer clones in tumors, could serve individually as biomarkers but had a higher predictive power as combinations of two biomarkers. We showed that PD-1 inhibition neither consistently enhanced all antitumorigenic factors nor suppressed all protumorigenic factors but ultimately reduced the tumor carrying capacity. Collectively, our predictions suggest several candidate biomarkers that might effectively predict the response to pembrolizumab monotherapy and potential therapeutic targets to develop treatment strategies for metastatic TNBC.

Abstract A067: Myc drives phenotypic heterogeneity, metastasis, and therapy resistance in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDAc) ranks among the top three most aggressive cancers in the United States and is projected to increase in incidence over the next few years. Standard of care treatment for PDAc consists of a cocktail of harsh chemotherapies, which have improved overall survival by only a few percentage points—to a 5-year survival rate of 11%. One commonly deregulated pathway in PDAc is c-MYC (MYC), a potent transcription factor. MYC plays an important role in tumor progression and its deregulation has been correlated with tumor aggressiveness and therapeutic resistance in PDAc and other cancers. Recently, oncogenic MYC expression has been shown to regulate elements of the tumor microenvironment (TME) in mouse models of multiple cancers. In PDAc, MYC’s expression has been linked to a desmoplastic immune suppressive TME, yet the specific mechanism has yet to be described. Here, we present a novel genetically engineered mouse model (GEMM) of PDAc that can be used to better model the disease and to interrogate questions of how MYC regulates the tumor immune and stromal microenvironments. Our KMCERT2 model has inducible Cre-driven expression of both mutant Kras and low deregulated Myc in the pancreas. We show that deregulated MYC cooperates with KRASG12D in the adult pancreas to drive PDAc, and our model recapitulates inter- and intra-tumoral heterogeneity seen within clinical PDAc populations. Currently, a majority of murine studies of PDAc are performed using an embryonic KrasG12D- and p53 loss/mutant-driven PDAc model (KPC). RNA- and DNA sequencing on both microdissected autochthonous tumor specimens and KMCERT2 tumor-derived cell lines was conducted to further understand the mechanisms underlying our observed phenotypes. In contrast to the KPC model, our inducible KMCERT2 model of PDAc displays genetic changes, such as CDKN2A and SMAD4 loss, comparable to human disease. Interestingly, multiplexed immunohistochemistry analysis of immune cell composition of spontaneous KMCERT2 tumors compared to the commonly used KPC shows an increased density of antigen presenting cells (APCs) within MYC-driven tumors. Human PDAc is often resistant to standard of care therapies such as gemcitabine and FOLFIRINOX. Orthotopic therapeutic studies using our KMCERT2 tumor-derived cell lines demonstrate a similar resistance to these therapies, allowing us to use this model to better understand the mechanisms leading to therapeutic resistance and to test new therapies. In addition, we find consistent metastasis to the liver in both spontaneous and orthotopic transplant settings. Together, this work investigates the role of deregulated MYC expression in metastatic behavior, immune phenotypes, and therapeutic response in murine PDAc. It also provides both spontaneous and orthotopic mouse models of PDAc that recapitulate the heterogeneous and highly metastatic nature of the human disease, allowing for important therapeutic testing opportunities. Citation Format: Isabel A. English, Patrick J. Worth, Amy S. Farrell, Brittany L. Allen-Petersen, Vidhi Shah, Courtney Betts, Carl Pelz, Xiaoyan Wang, Colin J. Daniel, Mary C Thoma, Lisa M Coussens, Ellen M Langer, Rosalie C Sears. Myc drives phenotypic heterogeneity, metastasis, and therapy resistance in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A067.

Abstract 880: MYC drives phenotypic heterogeneity, metastasis, and therapy resistance in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDAC) ranks among the top three most aggressive cancers in the United States and is projected to increase in incidence over the next few years. Standard of care treatment for PDAC consists of a cocktail of harsh chemotherapies, which have improved overall survival by only a few percentage points - to a 5-year survival rate of 10%. One commonly deregulated pathway in PDAC is c-MYC (MYC), a potent transcription factor. MYC plays an important role in tumor progression and its deregulation has been correlated with tumor aggressiveness and therapeutic resistance in PDAC and other cancers. Recently, oncogenic MYC expression has been shown to regulate elements of the tumor microenvironment (TME) in mouse models of multiple cancers. In PDAC, MYC’s expression has been linked to a desmoplastic immune suppressive TME, yet the specific mechanism has yet to be described. Here, in order to better model the disease and to interrogate questions of how MYC regulates the tumor immune and stromal microenvironment, we have generated a novel genetically engineered mouse model (GEMM) of PDAC. Our model (KMCERT2) has inducible Cre-driven expression of both mutant Kras and low deregulated Myc in the pancreas. We have found that deregulated MYC cooperates with KRASG12D in the adult pancreas to drive PDAC in our inducible KMCERT2 mouse model and that our model recapitulates inter- and intra-tumoral heterogeneity seen within clinical PDAC populations as well as consistent metastasis to liver in both spontaneous and orthotopic transplant settings. Currently, a majority of murine studies of PDAC are performed using an embryonic KrasG12D- and p53 loss/mutant-driven PDAC model (KPC). In contrast to the KPC model, our inducible KMCERT2 model of PDAC displays genetic changes, such as CDKN2A and SMAD4 loss, comparable to human disease. Interestingly, multiplexed immunohistochemistry analysis of immune cell composition of spontaneous KMCERT2 tumors compared to the commonly used KPC shows an increased density of antigen presenting cells (APCs) within MYC-driven tumors. Human PDAC is often resistant to standard of care therapies such as gemcitabine and FOLFIRINOX. Orthotopic therapeutic studies using our KMCERT2 cell lines demonstrate a similar resistance to these therapies. To further understand the mechanisms underlying our observed phenotypes, we have conducted RNAseq and DNA sequencing on both microdissected autochthonous tumor specimens and KMCERT2 tumor-derived cell lines. Together, this work investigates the role of deregulated MYC expression in metastatic behavior, immune phenotypes, and therapeutic response in murine PDAC. It also provides both spontaneous and orthotopic mouse models of PDAC that recapitulate the heterogeneous and highly metastatic nature of the human disease, allowing for important therapeutic testing opportunities. Citation Format: Isabel A. English, Patrick J. Worth, Amy S. Farrell, Brittany L. Allen-Petersen, Vidhi Shah, Courtney Betts, Carl Pelz, Xiaoyan Wang, Colin J. Daniel, Mary C. Thoma, Lisa M. Coussens, Ellen M. Langer, Rosalie C. Sears. MYC drives phenotypic heterogeneity, metastasis, and therapy resistance in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 880.

Abstract PO-061: Myc drives phenotypic heterogeneity, metastasis, and therapy resistance in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDAC) ranks among the top three most aggressive cancers in the United States and is projected to increase in incidence over the next few years. Standard of care treatment for PDAC consists of a cocktail of harsh chemotherapies, which have improved overall survival by only a few percentage points – to a 5-year survival rate of 10%. One commonly deregulated pathway in PDAC is c-MYC (MYC), a potent transcription factor. MYC plays an important role in tumor progression and its deregulation has been correlated with tumor aggressiveness and therapeutic resistance in PDAC and other cancers. Recently, oncogenic MYC expression has been shown to regulate elements of the tumor microenvironment (TME) in mouse models of multiple cancers. In PDAC, MYC’s expression has been linked to a desmoplastic immune suppressive TME, yet the specific mechanism has yet to be described. Here, in order to better model the disease and to interrogate questions of how MYC regulates the tumor immune and stromal microenvironment, we have generated a novel genetically engineered mouse model (GEMM) of PDAC. Our model (KMCERT2) has inducible Cre-driven expression of both mutant Kras and low deregulated Myc in the pancreas. We have found that deregulated MYC cooperates with KRASG12D in the adult pancreas to drive PDAC in our inducible KMCERT2 mouse model and that our model recapitulates inter- and intra-tumoral heterogeneity seen within clinical PDAC populations as well as consistent metastasis to liver in both spontaneous and orthotopic transplant settings. Currently, a majority of murine studies of PDAC are performed using an embryonic KrasG12D- and p53 loss/mutant-driven PDAC model (KPC). In contrast to the KPC model, our inducible KMCERT2 model of PDAC displays genetic changes, such as CDKN2A and SMAD4 loss, comparable to human disease. Interestingly, multiplexed immunohistochemistry analysis of immune cell composition of spontaneous KMCERT2 tumors compared to the commonly used KPC shows an increased density of antigen presenting cells (APCs) within MYC-driven tumors. Human PDAC is often resistant to standard of care therapies such as gemcitabine and FOLFIRINOX. Orthotopic therapeutic studies using our KMCERT2 cell lines demonstrate a similar resistance to these therapies. To further understand the mechanisms underlying our observed phenotypes, we have conducted RNAseq and DNA sequencing on both microdissected autochthonous tumor specimens and KMCERT2 tumor-derived cell lines. Together, this work investigates the role of deregulated MYC expression in metastatic behavior, immune phenotypes, and therapeutic response in murine PDAC. It also provides both spontaneous and orthotopic mouse models of PDAC that recapitulate the heterogeneous and highly metastatic nature of the human disease, allowing for important therapeutic testing opportunities. Citation Format: Isabel A. English, Patrick J. Worth, Amy T. Farrell, Brittany L. Allen-Petersen, Vidhi Shah, Courtney Betts, Xiaoyan Wang, Colin J. Daniel, Mary C. Thoma, Lisa M. Coussens, Ellen M. Langer, Rosalie C. Sears. Myc drives phenotypic heterogeneity, metastasis, and therapy resistance in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-061.

Oral mucosal immunotherapy for allergic rhinitis: A pilot study.

Background:The sublingual mucosa has been used for many years to apply allergenic extracts for the purpose of specific immunotherapy (IT). Although sublingual IT (SLIT) is both safe and efficacious, the density of antigen-presenting cells is higher in other regions of the oral cavity and vestibule, which make them a potentially desirable target for IT.Objective:To present the concept of oral mucosal IT (OMIT) and to provide pilot data for this extended application of SLIT.Methods:An open-label, 12-month, prospective study was undertaken as a preliminary step before a full-scale clinical investigation. Twenty-four individuals with allergic rhinitis received IT by applying allergenic extracts daily to either the oral vestibule plus oral cavity mucosa by using a glycerin-based toothpaste or to the sublingual mucosa by using 50% glycerin liquid drops. Adverse events, adherence rates, total combined scores, rhinoconjunctivitis quality-of-life questionnaire scores, changes in skin reactivity, and changes in serum antibody levels were measured for each participant.Results:No severe adverse events occurred in either group. The adherence rate was 80% for the OMIT group and 62% for the SLIT group (p = 0.61). Decreased total combined scores were demonstrated for both the OMIT group (15.6%) and the SLIT group (22.3%), although this decrease did not reach statistical significance in either group. Both groups achieved a meaningful clinical improvement of at least 0.5 points on rhinoconjunctivitis quality-of-life questionnaire. A statistically significant rise in specific immunoglobulin G4 (IgG4) was seen in both groups over the first 6 months of treatment.Conclusion:OMIT and SLIT demonstrated similar safety profiles and adherence rates. Measurements of clinical efficacy improved for both groups, but only changes in IgG4 achieved statistical significance. These pilot data provide enough evidence to proceed with a full-scale investigation to explore the role of OMIT in the long-term management of allergic rhinitis.

Geometrically Controlled Asymmetric Division of CD4+ T Cells Studied by Immunological Synapse Arrays

Similar to stem cells, naïve T cells undergo asymmetric division following activation. While asymmetric division of T cells has been shown to be an important mechanism for the generation of lymphocyte fate diversity during immune responses, key factors that influence whether T cells will undergo symmetric or asymmetric divisions are not completely understood. Here, we utilized immunological synapse arrays (ISAs) to begin to dissect mechanisms of asymmetric T lymphocyte division. ISAs are protein micropatterned surfaces composed of two segregated regions, activation sites and adhesion fields. Activation sites are small spots presenting activation signals such as anti-CD3 and anti-CD28, and adhesion fields are the remaining regions surrounding activation sites immobilized with interintercel adhesion molecule 1 (ICAM-1). By varying the size and the distance between the activation sites and measuring the incidence of asymmetric cell divisions, we found that the distance between activation sites is an important regulator of asymmetric division. Further analysis revealed that more symmetric divisions occurred when two nascent daughter cells stably interacted with two distinct activation sites throughout and following cytokinesis. In contrast, more asymmetric divisions occurred when only one daughter cell remained anchored on an activation site while the other daughter became motile and moved away following cytokinesis. Together, these results indicate that TCR signaling events during cytokinesis may repolarize key molecules for asymmetric partitioning, suggesting the possibility that the density of antigen presenting cells that interact with T cells as they undergo cytokinesis may be a critical factor regulating asymmetric division in T cells.

Distribution of Antigen Presenting Cells in the Human Cornea: Correlation of In Vivo Confocal Microscopy and Immunohistochemistry in Different Pathologic Entities

Purpose: The purpose of this study was to determine the quantity and distribution of antigen presenting cells (APC) in various inflammatory and non-inflammatory corneal diseases, comparing in vivo confocal microscopy (IVCM) and immunohistochemistry.Material and methods: Corneae of 41 eyes, composed of group 1 (status post herpes-keratitis), group 2 (keratoconus) and group 3 (graft rejection after keratoplasty) were investigated. IVCM was used preoperatively to assess the distribution and density of dendritic cells in the corneal center versus the paracentral area. Afterwards, all patients underwent penetrating keratoplasty. The host corneas were analyzed by immunohistochemistry for antigen presenting cell distribution, density and characterization by using specific markers for CD207/Langerin, CD209/DC-SIGN and HLA-DR. The IVCM findings were compared with immunohistochemistry results in the corneal epithelium.Results: Cells with branching dendritic morphology were visualized by IVCM mainly in the basal epithelial layer and subepithelial nerve plexus of the central and paracentral cornea. The density of APC in IVCM decreased in all groups towards the central part of the cornea. The highest gradient was observed in group 2, followed by groups 1 and 3. The corneal paracenter showed similiar distribution of APC in group 1 and 2 (76.7 cells/mm2 and 74.4 cells/mm2). The highest density of central APC was observed in group 1 (53.76 cells/mm2), followed by group 3 (27.0 cells/mm2) and group 2 (24.2 cells/mm2). In immunohistochemistry positive stained, APC were distributed similarly to IVCM but with a higher density (p < 0.05).Conclusion: Distribution, density and stage of maturation of corneal epithelial APCs can be evaluated on morphological basis by IVCM. However, the corneal APCs density was about three-fold lower compared to immunohistochemistry findings.

Biodegradable dissolving microneedle arrays effectively deliver antigens and adjuvants to skin DCs for the induction of antigen specific immune responses. (48.12)

Abstract The skin contains a high density of antigen presenting cells making it an attractive target for vaccine delivery. However, the remarkable barrier function of the skin continues to present a formidable obstacle to topical vaccine delivery. To overcome this barrier we designed carboxy-methyl cellulose microneedle arrays (MNAs) to topically deliver antigens and adjuvants into the skin. MNAs were designed and fabricated to enable advantages in penetration, delivery, and diversity of biocompatibility over existing skin delivery technologies. Initially we fabricated MNAs with integrated tracer antigens. Following MNA immunization labeled antigens were identified in dendritic cells in human and murine skin, and in the draining lymph nodes of immunized animals. To evaluate immunogenicity, we incorporated the model antigen OVA in combination with various adjuvants into MNAs. MNA-mediated delivery of low dose antigen/adjuvant induced potent and durable CTL responses compared to those generated by traditional intradermal immunization. Further, MNA immunization utilizing B16 tumor cell lysates as a source of antigen induced B16 specific DTH reactions and inhibited tumor growth in a B16 tumor model. Taken together, these results demonstrate the feasibility of the use of CMC microneedle arrays for cutaneous immunization and suggest potentially broad applicability for the co-delivery of structurally diverse antigens and adjuvants.