Immunodetection of myeloid and plasmacytoid dendritic cells in mammary carcinomas of female dogs

ABSTRACT: Dendritic cells have attracted great interest from researchers as they may be used as targets of tumor immune evasion mechanisms. The main objective of this study was to evaluate the relationship between the dendritic cells (DCs) subpopulation in simple type mammary carcinomas in female dogs. Two groups of samples were used: the control group consisted of 18 samples of mammary tissue without changes and the tumor group with 26 simple type mammary carcinomas. In these groups, we evaluated the immunodetection of immature and mature myeloid DCs, plasmacytoid DCs and MHC-II. In mammary tumor, mature myeloid DCs predominated in the peritumoral region, while immature myeloid DCs and plasmacytoid DCs were evident in the intratumoral region. Immunostaining of MHC-II was visualized in mammary acini (control group), in tumor cells and inflammatory infiltration associated with tumors. The comparison between the control and tumor groups showed a statistically significant difference between immature myeloid DCs, mature myeloid DCs and plasmacytoid DCs. The immunodetection of MHC-II was not significant when comparing the groups. The predominance of immature DCs in the tumor group is possibly related to an inefficient immune response, promoting the development and survival of tumor cells. The presence of plasmacytoid DCs in the same group suggests a worse prognosis for female dogs with mammary tumors. Therefore, the ability of differentiation of canine dendritic cells could be influenced by neoplastic cells and by the tumor microenvironment.

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Murine hepatoma treatment with mature dendritic cells stimulated by Trichinella spiralis excretory/secretory products

Parasite ◽

10.1051/parasite/2020045 ◽

2020 ◽

Vol 27 ◽

pp. 47

Author(s):

Jing Ding ◽

Xiaolei Liu ◽

Bin Tang ◽

Xue Bai ◽

Yang Wang ◽

...

Keyword(s):

Dendritic Cells ◽

Tumor Growth ◽

Antitumor Effect ◽

Trichinella Spiralis ◽

Critical Role ◽

Tumor Model ◽

Control Group ◽

Tumor Inhibition ◽

Significant Difference ◽

Secretory Products

Excretory/Secretory Products (ESPs) of the nematode Trichinella spiralis contain antitumor-active substances that inhibit tumor growth. Mature dendritic cells (DCs) play a critical role in the antitumor immunity of the organism. As pathogen-derived products, it ought to be discussed whether T. spiralis ESPs will reduce the antitumor effect of mature DCs from the host before it is applied to patients’ tumors. Therefore, the aim of this work was to evaluate the immunological effect of DCs stimulated by T. spiralis ESPs in H22 tumor-bearing mice. H22 tumor model mice in this study were randomly divided into four groups according to the treatment: PBS control group, ESP group, DCs group, and DCs stimulated with T. spiralis ESP (ESP+DCs group). The antitumor effect was evaluated by tumor inhibition rate and cytokine detection using ELISA. The results showed significant inhibition in tumor growth in the ESP+DCs, DCs and ESP groups when compared with the PBS control group (p < 0.01, p < 0.01, and p < 0.05, respectively). However, no significant difference was observed on tumor inhibition rates between the ESP+DCs and DCs groups. The decrease in IL-4, IL-6, and IL-10, and the increase in IFN-γ between the DCs and ESP+DCs groups were also not significant. Therefore, DCs stimulated by ESP did not reduce the antitumor effect of mature DCs, which demonstrated that the T. spiralis ESP would not affect the antitumor effect of mature DCs by modulating the immune response of the host, and that ESPs are safe in antitumor immunology when applied in a tumor model mice.

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The effect of human amniotic epithelial cell on dendritic cell differentiation of peripheral blood monocytes: An experimental study

International Journal of Reproductive BioMedicine ◽

10.18502/ijrm.v13i6.7286 ◽

2020 ◽

Author(s):

Bahare Keshavarzi ◽

Meraj Tabatabaei ◽

Amir Hasan Zarnani ◽

Fahime Ramezani Tehrani ◽

Mahmood Bozorgmehr ◽

...

Keyword(s):

Dendritic Cells ◽

Amniotic Membrane ◽

Peripheral Blood ◽

Normal Pregnancy ◽

Interleukin 4 ◽

Control Group ◽

Blood Monocytes ◽

Peripheral Blood Monocytes ◽

Dendritic Cell Differentiation ◽

Significant Difference

Background: The amniotic membrane plays an important role in maintaining a healthy pregnancy. The main population cells from amniotic membrane include human amnion epithelial cells (hAECs) which have been shown to possess immunomodulatory properties. Objective: The proximity of hAECs with monocyte leads to the generation of tollerogenic dendritic cells. Materials and Methods: hAECs were obtained from normal pregnancy. Peripheral blood monocytes were isolated by anti-CD14 MACS method. Co-cultures of monocytes and hAECs were established in Transwell chambers supplemented with granulocytemacrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) in the absence and presence of lipopolysaccharide (LPS) to produce immature and mature DCs, respectively. Immunophenotyping of the obtained DCs was done through flow cytometry and the production of cytokines was measured by ELISA. Mixed leukocyte Reaction (MLR) was also performed for the functional assessment of DCs. Results: Immunophenotyping of [hAECs - Immature DC (iDC)] and [hAECs - iDC] + LPS cells revealed that the expression of CD1a, CD80, CD86, CD40, HLA-DR, and CD83 markers showed no significant difference as compared with the control group (iDCs and mDCs alone). In the [hAECs-iDCs] + LPS cells, the percentage of CD14 cells at the ratio of 1:2.5 showed significant differences compared to the control group. The production of IL-10 and IL-12 showed no significant difference in any of the cultures as compared to the control groups. Also, co-cultured DCs did not inhibit proliferation of lymphocyte. Conclusion: Our findings show that factors secreted from cultured hAECs are unable to generate of tollerogenic dendritic cells. To achieve a better understanding of other mechanisms more investigations are needed. Key words: Amniotic membrane, Dendritic cells, Human placenta, Immunomodulation, Monocyte.

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Plasma Interleukin-18 and Dendritic Cells in Males with Psoriasis Vulgaris

Mediators of Inflammation ◽

10.1155/2007/61254 ◽

2007 ◽

Vol 2007 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Aldona Pietrzak ◽

Konrad Janowski ◽

Grażyna Chodorowska ◽

Anna Michalak-Stoma ◽

Jacek Rolinski ◽

...

Keyword(s):

Dendritic Cells ◽

Patient Group ◽

Psoriasis Vulgaris ◽

Control Group ◽

Skin Involvement ◽

Interleukin 18 ◽

Inflammatory Processes ◽

Plasmacytoid Dcs ◽

Dendritic Cell Subsets ◽

The Relationship

Peripheral blood dendritic cells seem to play a crucial role in psoriatic inflammatory processes. The aim of our study is to investigate the relationship between plasma interleukin-18 (IL-18) levels and blood dendritic cells in psoriatic patients. IL-18 plasma levels were measured by ELISA. Phenotypes of dendritic cell subsets were analyzed by double-colour flow cytometry. Plasma IL-18 level in psoriatic males was significantly higher, whereas counts of BDCA-2+ cells were lower than in the control group. The myeloid/plasmacytoid ratio was significantly higher in the patient group compared to the control one. In the patient group, significant negative correlations between plasma IL-18 level and both the BDCA-1+ and BDCA-2+ counts were found. BDCA-1+ counts correlated negatively with percentage of skin involvement. IL-18 seems to play a role in psoriasis pathogenesis. The decreased counts of blood plasmacytoid DCs in psoriatic patients might result from IL-18 down-regulation of plasmacytoid DC precursor proliferation.

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Thymus-homing peripheral dendritic cells constitute two of the three major subsets of dendritic cells in the steady-state thymus

Journal of Experimental Medicine ◽

10.1084/jem.20082232 ◽

2009 ◽

Vol 206 (3) ◽

pp. 607-622 ◽

Cited By ~ 134

Author(s):

JiChu Li ◽

JooHung Park ◽

Deborah Foss ◽

Irving Goldschneider

Keyword(s):

Dendritic Cells ◽

Normal Mouse ◽

Regulatory Protein ◽

Developmental Studies ◽

Mhc Ii ◽

Histocompatibility Complex ◽

Functional Implications ◽

Circulating Antigen ◽

Plasmacytoid Dcs ◽

Major Histocompatibility Complex Ii

Many dendritic cells (DCs) in the normal mouse thymus are generated intrathymically from common T cell/DC progenitors. However, our previous work suggested that at least 50% of thymic DCs originate independently of these progenitors. We now formally demonstrate by parabiotic, adoptive transfer, and developmental studies that two of the three major subsets of thymic DCs originate extrathymically and continually migrate to the thymus, where they occupy a finite number of microenvironmental niches. The thymus-homing DCs consisted of immature plasmacytoid DCs (pDCs) and the signal regulatory protein α–positive (Sirpα+) CD11b+ CD8α− subset of conventional DCs (cDCs), both of which could take up and transport circulating antigen to the thymus. The cDCs of intrathymic origin were mostly Sirpα− CD11b− CD8αhi cells. Upon arrival in the thymus, the migrant pDCs enlarged and up-regulated CD11c, major histocompatibility complex II (MHC II), and CD8α, but maintained their plasmacytoid morphology. In contrast, the migrant cDCs proliferated extensively, up-regulated CD11c, MHC II, and CD86, and expressed dendritic processes. The possible functional implications of these findings are discussed.

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Action of tacrolimus on Wistar rat kidneys implanted with Walker 256 carcinosarcoma

Acta Cirurgica Brasileira ◽

10.1590/s0102-86502010000100020 ◽

2010 ◽

Vol 25 (1) ◽

pp. 98-104 ◽

Cited By ~ 1

Author(s):

Cristiano Machado Inácio ◽

Ulrich Andréas Dietz ◽

Osvaldo Malafaia ◽

Jurandir Marcondes Ribas Filho ◽

Paulo Afonso Nunes Nassif ◽

...

Keyword(s):

Tumor Cells ◽

Wistar Rats ◽

Histological Analysis ◽

Statistical Significance ◽

Control Group ◽

Walker 256 Carcinosarcoma ◽

Tumor Group ◽

Male Wistar Rats ◽

Walker 256 ◽

The Right

PURPOSE: To evaluate the development of Walker 256 tumor in male Wistar rats treated with tacrolimus using an experimental kidney tumor model. METHODS: 40 male Wistar rats were divided into four groups: Tumor group (TU) (n=10), Tacrolimus-Tumor group (TT) (n=10), Tacrolimus group (TC) (n=10) and Control group (C) (n=10). Treatment with tacrolimus was performed in groups TT and TC. Under anesthesia, the right kidney of each animal of TU and TT was accessed through a supraumbilical incision and inoculated with a 0.1mL solution containing 2x10(6) tumor cells (Walker 256 carcinosarcoma tumor cells). Group TC was treated with a saline solution. All the animals of groups TC and TT were treated with tacrolimus (5mg/kg/day) by gavage for 15 days. TU group animals received saline by gavage for 15 days. On the 15th postoperative day, all animals were submitted to euthanasia and blood sampling for analysis of serum creatinine (Cr) and blood urea nitrogen (BUN). Abdominal gross examination was performed, the right kidney removed and prepared for histological analysis by hematoxylin-eosin staining. The resulting data were submitted to statistical analysis by ANOVA. RESULTS: Statistical significance was found when comparing creatinine level between groups TU, TT and TC -TT group culminated with a marked increased in creatinine levels (Cr=1.013 ± 0.3028 mg/mL), TU group (Cr=0.5670 ± 0.03536 mg/dL) P=0.00256, TC group (Cr =0.711 ± 0.1653 mg/mL) P= 0.02832. Statistical significance was found when comparing BUN levels in TT group (71.32 ± 17.14 mg/mL), compared with TU group (45.83 ± 5.046 mg/dL), P=0.000318. There were no statistically significant differences between groups TT and TC (61.23 ± 9.503 mg/mL) P=0.7242. Histological analysis showed a poor evolution in TT group with multiple foci of hemorrhage and cortical invasion by the Walker tumor. CONCLUSION: The Tacrolimus-treated group developed a more aggressive tumor and a drug-related nephrotoxic effect.

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AB0023 DENDRITIC CELLS AS A PROMINENT MARKERS OF AUTOIMMUNE DISEASES

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.2293 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 1045.2-1045

Author(s):

M. Korolev ◽

Y. Kurochkina ◽

N. Banshhikova ◽

V. Omelchenko ◽

A. Akimova ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Dendritic Cells ◽

Autoimmune Diseases ◽

B Lymphocytes ◽

Peripheral Blood ◽

Group Analysis ◽

Control Group ◽

Hla Dr ◽

Asas Criteria ◽

Plasmacytoid Dcs

Background:Dendritic cells (DCs) are known to contribute to the pathogenesis of different autoimmune diseases. It is clear nowadays the role of DCs in rheumatoid arthritis (RA) but not well investigated in Axial spondylitis (AxSpA). DCs are a heterogeneous population and can be divided into groups: myeloid (mDCs) and plasmacytoid (pDCs). DCs can induce both immune response and tolerance.Objectives:To investigate the subpopulations of peripheral blood myeloid and plasmacytoid DCs in patients with early stage of RA (duration of illness up to 12 months) and AS.Methods:The study include sixty five patients with early forms of diseases including 55 patients with RA and 10 patients with AxSpA. Diagnosis RA was established according ACR/EULAR criteria (2010). Diagnosis AxSpA was established according ASAS criteria. All patients received conventional synthetic DMARDs. Thirty patients with osteoarthritis (OA) used as a control group. Analysis of the content of the B-lymphocytes, myeloid and plasmacytoid DCs was carried out by flow cytometry. B-lymphocytes, subtypes of peripheral blood DCs were characterized by the following phenotypes: myeloid DCs (CD3-CD14-CD19-HLA-DR + CD11c + CD123-), plasmacytoid DCs (CD3-CD14-CD19-HLA-DR + CD11c-CD123 +), B-lymphocytes (CD19 +). Analyses were performed before treatment and after 3 and 6 months.Results:Patients with early RA are characterized by significant evaluation of the population of myeloid DCs in comparison of patients with osteoarthritis (25.3% vs 21.5, p=0.005). Furthermore, the difference was found in the number of cells with the phenotype B-lymphocytes: 5.7% vs 3.1%, p = 0.0007). No significant differences were observed in the number of plasmocytoid DCs. After 3 and 6 month of observation we detected reducing amount of myeloid DCs 26.7% vs 20.1% vs 16.4% respectively. Disease activity according to DAS28 droped to low (4.32 to3.06, p=0.03). Patients with AxSpA are characterized a lower mDCs levels in compared with RA (19.3% vs 26.7, p=0.07). After 6 month of investigation we detected decreasing mDCs (19.3% to 14.2%, p=0.05). The percent of pDCs were constant and did not differ from the level of healthy donors.Conclusion:The data obtained indicate that early form of rheumatic diseases namely rheumatoid arthritis and axial spondylitis have the common features such as the dominance of mDCs and their decreasing in reduction of activity of disease.Disclosure of Interests:None declared

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Pomalidomide Promotes the Maturation of Healthy Donors and Multiple Myeloma Patients Derived-Dendritic Cells

Blood ◽

10.1182/blood-2021-146768 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 4702-4702

Author(s):

Xi Wang ◽

Feifei Che ◽

Wanjun Cao ◽

Zichen Ye ◽

Hong Zheng ◽

...

Keyword(s):

Multiple Myeloma ◽

Dendritic Cells ◽

Peripheral Blood ◽

Conflicts Of Interest ◽

Control Group ◽

Incubation System ◽

Hla Dr ◽

Healthy Donors ◽

Tnf Α ◽

Significant Difference

Abstract Abstract: Objective To investigate the effect of pomalidomide on the maturation of monocyte derived dendritic cells (moDCs) from healthy donors (HDs) and multiple myeloma (MM) patients. Method Peripheral blood mononuclear cells (PBMCs) were isolated from the peripheral blood of HDs and MM patients. The generation of moDCs from monocytes in PBMCs was conducted by the incubation of 7 days in a medium consisting of RPMI 1640 medium, 5% human serum, 800U/mL GM-CSF, 500U/mL IL-4, 100U/mL penicillin and 0.1mg/mL streptomycin. During this period, the incubation system was administrated with pomalidomide at 10 µM or 1×PBS as the control group. On the 8 th day, cells were harvested, and the immunophenotyping of cells were analyzed by the flow cytometry. The CD80+CD86+ cell population in total cells is gated as DCs in the FACS analyzing system. Then, the median fluorescence intensity (MFI) of surface markers CD40 and HLA-DR as well as the proportion of CD40+ DCs and HLA-DR+ DCs in total DCs were analyzed respectively. In addition, supernatant from the incubation system with or without pomalidomide administration was collected and detected for the concentration of cytokines IL-12, TNF-α and MIP-1α. Results The proportion of CD80+CD86+ cells in total cells was higher in HD group (n=15) than in MM patient group (n=11), but there was no statistically significant difference (93.49%±6.43% vs 77.04%±27.17%, P=0.094). When analyzing all the HD-derived moDCs (n=15), pomalidomide significantly enhanced the MFI of CD40 (P=0.003) and HLA-DR (P=0.040) on moDCs when compared with the control group. Meanwhile, the proportion of CD40+ DCs (P=0.008) and HLA-DR+ DCs (P=0.032) in total DCs was significantly higher in pomalidomide group than in control group. When analyzing all MM patients-derived moDCs (n=11), pomalidomide significantly enhanced the MFI of CD40 (P=0.047) and HLA-DR (P=0.006) on moDCs when compared with the control group. Meanwhile, the proportion of HLA-DR+ DCs in total DCs was significantly higher in pomalidomide group than in the control group (P=0.000). Moreover, pomalidomide treated HD-derived moDCs (n=8) produced 192% IL-12 (P=0.020), 110% TNF-α (P=0.006) and 112% MIP-1α (P=0.055) of untreated moDCs. However, when analyzing MM patients-derived moDCs (n=10), the expression of IL-12 (P=0.458), TNF-α (P=0.377) and MIP-1α (P=0.248) from moDCs showed no significant difference between pomalidomide group and the control group. Conclusions Pomalidomide at 10 µM can promote the maturation of both HD-derived moDCs and MM patients-derived moDCs. Pomalidomide shows potential to be a DC adjuvant for DC-based therapeutic strategies, such as DC vaccine and DC cell-therapy in MM. Key words: Pomalidomide; Monocyte derived Dendritic Cells; Multiple Myeloma; DC Adjuvant Disclosures No relevant conflicts of interest to declare.

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Arginine Alters miRNA Expression Involved in Development and Proliferation of Rat Mammary Tissue

Animals ◽

10.3390/ani11020535 ◽

2021 ◽

Vol 11 (2) ◽

pp. 535

Author(s):

Gang Zhou ◽

Qiaoyun Xu ◽

Feifan Wu ◽

Mengzhi Wang ◽

Lianmin Chen ◽

...

Keyword(s):

High Throughput Sequencing ◽

Target Genes ◽

Control Diet ◽

Rna Extraction ◽

Experimental Period ◽

Differentially Expressed ◽

Mammary Tissue ◽

Control Group ◽

Sequencing Analysis ◽

Significant Difference

This study was designed to determine the effects of dietary arginine on development and proliferation in rat mammary tissue through changes in miRNA profiles. Twelve pregnant Wistar rats were allocated randomly to two groups. A basal diet containing arginine or the control diet containing glutamate on an equal nitrogen basis as the arginine supplemented diet were used. The experiment included a pre-experimental period of four days before parturition and an experimental period of 17 days after parturition. Mammary tissue was collected for histology, RNA extraction and high-throughput sequencing analysis. The greater mammary acinar area indicated that arginine supplementation enhanced mammary tissue development (p < 0.01). MicroRNA profiling indicated that seven miRNA (miR-206-3p, miR-133a-5p, miR-133b-3p, miR-1-3p, miR-133a-3p, miR-1b and miR-486) were differentially expressed in response to Arginine when compared with the glutamate-based control group. In silico gene ontology enrichment and KEGG pathway analysis revealed between 240 and 535 putative target genes among the miRNA. Further verification by qPCR revealed concordance with the differential expression from the sequencing results: 17 of 28 target genes were differentially expressed (15 were highly expressed in arginine and 2 in control) and 11 target genes did not have significant difference in expression. In conclusion, our study suggests that arginine may potentially regulate the development of rat mammary glands through regulating miRNAs.

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Dasatinib Promotes the Maturation of Healthy Donors and Chronic Myelogenous Leukemia Patients Derived Dendritic Cells

Blood ◽

10.1182/blood-2020-138462 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 53-54

Author(s):

Wangjun Cao ◽

Lin He ◽

Hong Zheng ◽

Xiaobing Huang ◽

Xi Yang ◽

...

Keyword(s):

Dendritic Cells ◽

Chronic Myelogenous Leukemia ◽

Myelogenous Leukemia ◽

Control Group ◽

Surface Markers ◽

Expression Levels ◽

Hla Dr ◽

Healthy Donors ◽

Significant Difference ◽

Enhanced Expression

Dasatinib has been discovered to obtain immunomodulatory effects in addition to the targeting effect towards BCR-ABL in chronic myelogenous leukemia (CML) patients. But the effect of dasatinib on dendritic cells (DCs) is still not fully understood. Objective To investigate the effect of dasatinib on the maturation of monocyte derived dendritic cells (moDCs) from healthy donors (HDs) and CML patients. Method Peripheral blood mononuclear cells (PBMCs) were isolated from HDs (n=14) and CML patients (n=14) who had got remission of MR4.5 with imatinib treatment. The generation of moDCs was completed after 7 days of incubation in DC I medium, and another 3 days of incubation in DC II medium with or without 25nM dasatinib. On the 10th day, the moDCs were harvested and analyzed for the expression of surface markers CD83, CD80, CD86, CD40 and HLA-DR to reflect the maturation of the moDCs by flow cytometry. Results When analyzing the moDCs from all the 14 HDs together, dasatinib significantly enhanced the expression levels of the surface marker CD83 (P=0.039), CD40 (P=0.002) and HLA-DR (P=0.000) on moDCs compared with the control group, but there was no statistically significant difference in CD80 (P=0.073) and CD86 (P=0.897). Differently, when analyzing the moDCs derived from all the 14 patients together, there was no statistically significant difference in the expression levels of CD80 (P=0.086), CD86 (P=0.166), CD83 (P=0.674), CD40 (P=0.574) and HLA-DR (P=0.561) on moDCs between the dasatinib group and the control group. However, moDCs derived from 3 of the 14 patients show the enhanced expression of all the five surface makers with dasatinib administration compared to the control group. Besides, the moDCs derived from 6 of the 14 patients show the enhanced expression of at least one of the five surface markers. Notably, compared with moDCs derived from HD group (n=14), moDCs from patient group (n=14) express lower levels of CD80 (P=0.340), CD86 (P=0.007), CD40 (P=0.010), CD83 (P=0.019) and HLA-DR (P=0.036). Conclusion Dasatinib at the concentration of 25nM can efficiently promote the maturation of HD-derived moDCs in vitro, whereas this effect only occurs in part of the CML patients. And the moDCs from patients generally show much lower levels of the maturation associated surface makers compared with moDCs from HDs. Dasatinib shows potential as a DC adjuvant to be applied in DC-based therapeutic strategies, such as DC vaccine and DC cell-therapy. Disclosures No relevant conflicts of interest to declare.

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Role of CCL21 on the Transcriptional Regulation of MHC II in Malignant Glioma Infiltrating Plasmacytoid Dendritic Cells

Proceedings of IMPRS ◽

10.18060/22737 ◽

2018 ◽

Vol 1 (1) ◽

Author(s):

Sharlé Newman ◽

Sreenivasulu Chintala ◽

Mario Henriquez ◽

Mahua Dey

Keyword(s):

T Cells ◽

Dendritic Cells ◽

Tumor Cells ◽

Immune Cells ◽

Plasmacytoid Dendritic Cells ◽

Potential Therapeutic Target ◽

Mhc Ii ◽

Immunosuppressive Tumor Microenvironment ◽

Potential Impact

Background and Hypothesis: Glioblastoma (GBM) is a malignant brain tumor characterized by high tumor heterogeneity and an immunosuppressive tumor microenvironment (TME). Immunomodulation approaches have been investigated, but outcomes remain poor. Several studies describe the functional deregulation of immune cells including, T cells, dendritic cells (DC), and macrophages. Plasmacytoid dendritic cells (pDC), which accumulate in the GBM TME, are shown to have an immunosuppressive phenotype characterized by a lack of IFN-[Symbol] secretion and upregulation of MHC II. MHC II presentation is transcriptionally regulated by several factors produced by tumor cells including, TGFβ, TNFα, and IL10 through the modulation of CIITA, the catalytic component of the enhanceosome. GBM tumor cells secrete several chemokines/cytokines, which may regulate MHC II expression in pDCs. We hypothesize that chemokine CCL21 transcriptionally upregulates MHC II through the activation of CIITA in pDC. Experimental Design/Project methods: We performed experiments using two GBM tumor cells models GL261 and CT2A and used western blot, PCR, immunohistochemistry, immunofluorescence, and flow cytometry to determine the levels of CCL21 and its ligands ACKR3/4 in tumor cells and pDC. Results: We observed overexpression of CCL21 in GBM and upregulation of MHCII in tumor associated pDC. We predict that inhibition of CCL21 will lead to downregulation of MHC II in tumor associated pDC which could potentially lead to reversal of the immunosuppressive TME by presenting the antigens to T cells. Conclusions/Potential Impact: The results of this study can elucidate novel mechanisms of MHCII regulation and identify CCL21 as a potential therapeutic target for immunotherapy development in GBM.

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