scholarly journals Overexpression of miR-223 Promotes Tolerogenic Properties of Dendritic Cells Involved in Heart Transplantation Tolerance by Targeting Irak1

2021 ◽  
Vol 12 ◽  
Author(s):  
Shun Yuan ◽  
Yuanyang Chen ◽  
Min Zhang ◽  
Zhiwei Wang ◽  
Zhipeng Hu ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Heart Transplantation ◽  
Immune Cell ◽  
Transplant Rejection ◽  
Control Group ◽  
Rna Molecules ◽  
Heart Graft ◽  
Non Coding Rna ◽  
Antigen Presenting

Dendritic cells (DCs) are key mediators of transplant rejection. Numerous factors have been identified that regulate transplant immunopathology by modulating the function of DCs. Among these, microRNAs (miRNAs), small non-coding RNA molecules, have received much attention. The miRNA miR-223 is very highly expressed and tightly regulated in hematopoietic cells. It plays an important role in modulating the immune response by regulating neutrophils and macrophages, and its dysregulation contributes to multiple types of immune diseases. However, the role of miR-223 in immune rejection is unclear. Here, we observed expression of miR-223 in patients and mice who had undergone heart transplantation and found that it increased in the serum of both, and also in DCs from the spleens of recipient mice, although it was unchanged in splenic T cells. We also found that miR-223 expression decreased in lipopolysaccharide-stimulated DCs. Increasing the level of miR-223 in DCs promoted polarization of DCs toward a tolerogenic phenotype, which indicates that miR-223 can attenuate activation and maturation of DCs. MiR-223 effectively induced regulatory T cells (Tregs) by inhibiting the function of antigen-presenting DCs. In addition, we identified Irak1 as a miR-223 target gene and an essential regulator of DC maturation. In mouse allogeneic heterotopic heart transplantation models, grafts survived longer and suffered less immune cell infiltration in mice with miR-223-overexpressing immature (im)DCs. In the miR-223-overexpressing imDC recipients, T cells from spleen differentiated into Tregs, and the level of IL-10 in heart grafts was markedly higher than that in the control group. In conclusion, miR-223 regulates the function of DCs via Irak1, differentiation of T cells into Tregs, and secretion of IL-10, thereby suppressing allogeneic heart graft rejection.

scholarly journals TIGIT-Fc as a Potential Therapeutic Agent for Fetomaternal Tolerance

2021 ◽  
Vol 12 ◽  
Author(s):  
Wenyan Fu ◽  
Renfei Cai ◽  
Zetong Ma ◽  
Tian Li ◽  
Changhai Lei ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Immune Cell ◽  
Therapeutic Potential ◽  
Interleukin 10 ◽  
Immunological Tolerance ◽  
Tolerogenic Dendritic Cells ◽  
Immune Cell Subsets ◽  
Pregnant Mice ◽  
Antigen Presenting

The perfect synchronization of maternal immune-endocrine mechanisms and those of the fetus is necessary for a successful pregnancy. In this report, decidual immune cells at the maternal-fetal interface were detected that expressed TIGIT (T cell immunoreceptor with Ig and ITIM domains), which is a co-inhibitory receptor that triggers immunological tolerance. We generated recombinant TIGIT-Fc fusion proteins by linking the extracellular domain of TIGIT and silent Fc fragments. The treatment with TIGIT-Fc of human decidual antigen presenting cells (APCs), the decidual dendritic cells (dDCs), and decidual macrophages (dMϕs) increased the production of interleukin 10 and induced the decidua APCs to powerfully polarize the decidual CD4+ T cells toward a classic TH2 phenotype. We further proposed that Notch signaling shows a pivotal effect on the transcriptional regulation in decidual immune cell subsets. Moreover, the administration of TIGIT-Fc to CBA/J pregnant mice at preimplantation induced CD4+ forkhead box P3+ (Foxp3+) regulatory T cells and tolerogenic dendritic cells and increased pregnancy rates in an abortion-prone animal model stress. The results suggested the therapeutic potential of the TIGIT-Fc fusion protein in reinstating immune tolerance in failing pregnancies.

Abstract 119: Donor Macrophages Modulate Cellular Rejection After Heart Transplantation

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Benjamin Kopecky ◽  
Junedh Amrute ◽  
Hao Dun ◽  
C. Corbin Frye ◽  
DANIEL KREISEL ◽  
...  
Keyword(s):  
T Cells ◽  
Heart Transplantation ◽  
Single Cell ◽  
Rna Sequencing ◽  
Expression Profiles ◽  
Transplant Rejection ◽  
Gene Expression Profiles ◽  
Single Cell Rna Sequencing ◽  
Monocytes And Macrophages ◽  
Antigen Presenting

Heart transplant rejection is common and is associated with significant morbidity and mortality. Current immunosuppressive therapies primarily target recipient T-cells and have a multitude of untoward effects including infections, malignancies, and end-organ damage. Recent studies implicate the roles of antigen presenting cells towards pathogenesis of allograft rejection through recruitment and activation of T-cells. The importance of antigen presenting cell origin, identity, and functional importance remains unknown. Using complimentary imaging and single cell RNA sequencing techniques, we show that donor and recipient monocytes and macrophages co-exist after heart transplantation. These myeloid populations have diverse transcriptional signatures that evolve throughout ongoing rejection. Donor macrophages can be defined ontologically and based on their expression of C-C chemokine receptor 2 (CCR2) and expression of MHC-II. Donor CCR2+ and CCR2- populations can be further defined based on their gene expression profiles, highlighting the marked heterogeneity in the donor macrophage population. Selective depletion of CCR2+ macrophages result in prolonged allograft survival. We use longitudinal single cell RNA sequencing to show that donor CCR2+ and CCR2- macrophages have distinct activation mechanisms such that donor CCR2+ macrophages signal through MyD88/NF-kB. Conditional depletion of MyD88 in donor macrophages recapitulates the donor CCR2+ depletion phenotype. Further interrogation of MyD88 conditionally depleted allografts shows reduced T-cell alloreactivity, holding promise for a potential therapeutic target pathway. Together, we show the molecular identity, diversity, and evolution of donor and recipient monocytes and macrophages as well as the functional relevance and activation pathways of donor macrophages in cardiac allografts.

scholarly journals Synthesis and Immunological Evaluation of a Single Molecular Construct MUC1 Vaccine Containing l-Rhamnose Repeating Units

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3137
Author(s):  
Md Kamal Hossain ◽  
Abhishek Vartak ◽  
Steven J. Sucheck ◽  
Katherine A. Wall
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Mouse Model ◽  
Current Approach ◽  
Control Group ◽  
Two Component ◽  
Anticancer Vaccines ◽  
Antigen Presenting ◽  
Immunological Evaluation ◽  
Targeting Strategy

A rhamnose targeting strategy for generating effective anticancer vaccines was successful in our previous studies. We showed that by utilizing natural anti-rhamnose antibodies, a rhamnose-containing vaccine can be targeted to antigen-presenting cells, such as dendritic cells. In this case, rhamnose (Rha) was linked directly to the liposomes bearing the antigen. However, in the current approach, we conjugated a multivalent Tri-Rha ligand with the antigen itself, making it a single component vaccine construct, unlike the previous two-component vaccine construct where Rha cholesterol and Mucin1 (MUC1) antigen were both linked separately to the liposomes. Synthesis required the development of a linker for coupling of the Rha-Ser residues. We compared those two systems in a mouse model and found increased production of anti-MUC1 antibodies and more primed antigen-specific CD4+ T cells in both of the targeted approaches when compared to the control group, suggesting that this one-component vaccine construct could be a potential design used in our MUC1 targeting mechanisms.

IMMU-46. ARTIFICIAL INTELLIGENCE-DIRECTED, GENE THERAPY-BASED TRANSDIFFERENTIATION OF GLIOBLASTOMA TO FUNCTIONAL DENDRITIC CELLS AS NOVEL CANCER IMMUNOTHERAPY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi103-vi103
Author(s):  
Dan Jin ◽  
Son Le ◽  
Mathew Sebastian ◽  
Dongjiang Chen ◽  
Linchun Jin ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Cell Fate ◽  
Antigen Processing ◽  
Immune Cell ◽  
Viral Vector ◽  
T Cell Response ◽  
Cell Trafficking ◽  
Novel Approach ◽  
Antigen Presenting

Abstract BACKGROUND Despite recent advances in tumor immunotherapy in solid tumors, success in GBM remains elusive, likely due to its poor immunogenicity and CNS barriers limiting immune cell trafficking. Here we describe a novel approach of stimulating glioma-specific immunity by transdifferentiating GBM cells in situ to induced dendritic cells (iDCs). METHODS We applied NETZEN, an integrated deep-learning and gene network-based ranking computational platform and identified cell fate determinants (CFDs) to convert GBM cells to DCs. CFDs were delivered using a viral vector. Transdifferentiation was assessed by immunophenotyping and iDCs functionally validated by their ability to prime naive T cells. RESULTS A four CFDs subnetwork anchored by PU.1 was sufficient to transdifferentiate mouse GBM cells to CD45+MHCII+ cells with high co-stimulatory CD80 expression and to induce nearly 98% of GBM cells to express 100-fold higher levels of MHCI. Consistent with a new identity of antigen-presenting cells (APC), the induced immune cells are growth arrested, exhibit 3-fold higher phagocytic activity and upregulate the canonical antigen processing and presenting machineries by 10-40 folds, resulting in 40-fold greater efficiency at processing ovalbumin and presenting SIINFEKL on MHCI compared to native GBM cells. Importantly, SIINFEKL-loaded iAPCs are capable of activating naive OTII-CD4+ and OTI-CD8+ T cells, indicating that they are DC-like. In addition, iDCs efficiently present tumor cell-intrinsic antigens and elicit >20-fold higher activation and cytotoxicity in tumor-specific T cells compared to native GBM cells. Lastly, intratumoral GBM-DC transdifferentiation in a syngeneic orthotopic GBM model produces a robust memory T cell response in deep cervical draining lymph nodes compared to control animals. CONCLUSIONS Our results comfirm that GBM-derived iDCs acquire functions similar to native DCs, and thus, lay the foundation for a novel therapeutic approach in which poorly immunogenic tumors like GBM may be forced to generate their own immunity from within through cell fate transdifferentiation.

Stimulation of autologous proliferative and cytotoxic T-cell responses by “leukemic dendritic cells” derived from blast cells in acute myeloid leukemia

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2764-2771 ◽  
Author(s):  
Beth D. Harrison ◽  
Julie A. Adams ◽  
Mark Briggs ◽  
Michelle L. Brereton ◽  
John A. Liu Yin
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Dendritic Cells ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Cell Responses ◽  
Cell Responses ◽  
Antigen Presenting ◽  
Acute Myeloid ◽  
Stimulation Of

Abstract Effective presentation of tumor antigens is fundamental to strategies aimed at enrolling the immune system in eradication of residual disease after conventional treatments. Myeloid malignancies provide a unique opportunity to derive dendritic cells (DCs), functioning antigen-presenting cells, from the malignant cells themselves. These may then co-express leukemic antigens together with appropriate secondary signals and be used to generate a specific, antileukemic immune response. In this study, blasts from 40 patients with acute myeloid leukemia (AML) were cultured with combinations of granulocyte-macrophage colony-stimulating factor, interleukin 4, and tumor necrosis factor α, and development to DCs was assessed. After culture, cells from 24 samples exhibited morphological and immunophenotypic features of DCs, including expression of major histocompatibility complex class II, CD1a, CD83, and CD86, and were potent stimulators in an allogeneic mixed lymphocyte reaction (MLR). Stimulation of autologous T-cell responses was assessed by the proliferative response of autologous T cells to the leukemic DCs and by demonstration of the induction of specific, autologous, antileukemic cytotoxicity. Of 17 samples, 11 were effective stimulators in the autologous MLR, and low, but consistent, autologous, antileukemic cytotoxicity was induced in 8 of 11 cases (mean, 27%; range, 17%-37%). This study indicates that cells with enhanced antigen-presenting ability can be generated from AML blasts, that these cells can effectively prime autologous cytotoxic T cells in vitro, and that they may be used as potential vaccines in the immunotherapy of AML.

scholarly journals Response of naive antigen-specific CD4+ T cells in vitro: characteristics and antigen-presenting cell requirements.

1992 ◽  
Vol 176 (5) ◽  
pp. 1431-1437 ◽  
Author(s):  
M Croft ◽  
D D Duncan ◽  
S L Swain
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Cd4 Cells ◽  
Peptide Antigen ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Antigen Presenting

Because of the low frequency of T cells for any particular soluble protein antigen in unprimed animals, the requirements for naive T cell responses in specific antigens have not been clearly delineated and they have been difficult to study in vitro. We have taken advantage of mice transgenic for the V beta 3/V alpha 11 T cell receptor (TCR), which can recognize a peptide of cytochrome c presented by IEk. 85-90% of CD4+ T cells in these mice express the transgenic TCR, and we show that almost all such V beta 3/V alpha 11 receptor-positive cells have a phenotype characteristic of naive T cells, including expression of high levels of CD45RB, high levels of L-selectin (Mel-14), low levels of CD44 (Pgp-1), and secretion of interleukin 2 (IL-2) as the major cytokine. Naive T cells, separated on the basis of CD45RB high expression, gave vigorous responses (proliferation and IL-2 secretion) to peptide antigen presented in vitro by a mixed antigen-presenting cell population. At least 50% of the T cell population appeared to respond, as assessed by blast transformation, entry into G1, and expression of increased levels of CD44 by 24 h. Significant contributions to the response by contaminating memory CD4+ cells were ruled out by demonstrating that the majority of the CD45RB low, L-selectin low, CD44 high cells did not express the V beta 3/V alpha 11 TCR and responded poorly to antigen. We find that proliferation and IL-2 secretion of the naive CD4 cells is minimal when resting B cells present peptide antigen, and that both splenic and bone marrow-derived macrophages are weak stimulators. Naive T cells did respond well to high numbers of activated B cells. However, dendritic cells were the most potent stimulators of proliferation and IL-2 secretion at low cell numbers, and were far superior inducers of IL-2 at higher numbers. These studies establish that naive CD4 T cells can respond vigorously to soluble antigen and indicate that maximal stimulation can be achieved by presentation of antigen on dendritic cells. This model should prove very useful in further investigations of activation requirements and functional characteristics of naive helper T cells.

540 Transcriptionally defined immune landscape in human gliomas

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A576-A576
Author(s):  
Pravesh Gupta ◽  
Minghao Dang ◽  
Krishna Bojja ◽  
Huma Shehwana ◽  
Tuan Tran ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cell ◽  
Single Cell ◽  
Rna Sequencing ◽  
Immune Cell ◽  
Myeloid Cell ◽  
Wild Type ◽  
Cell Clusters ◽  
Md Anderson ◽  
Antigen Presenting

BackgroundBrain immunity is largely myeloid cell dominated rather than lymphoid cells in healthy and diseased state including malignancies of glial origins called as gliomas. Despite this skewed myeloid centric immune contexture, immune checkpoint and T cell based therapeutic modalities are generalizably pursued in gliomas ignoring the following facts i) T cells are sparse in tumor brain ii) glioma patients are lymphopenic iii) gliomas harbor abundant and highly complex myeloid cell repertoire. We recognized these paradoxes pertaining to fundamental understanding of constituent immune cells and their functional states in the tumor immune microenvironment (TIME) of gliomas, which remains elusive beyond a priori cell types and/or states.MethodsTo dissect the TIME in gliomas, we performed single-cell RNA-sequencing on ~123,000 tumor-derived sorted CD45+ leukocytes from fifteen genomically classified patients comprising IDH-mutant primary (IMP; n=4), IDH-mutant recurrent (IMR; n=4), IDH-wild type primary (IWP; n=3), or IDH-wild type recurrent (IWR; n=4) gliomas (hereafter referred as glioma subtypes) and two non-glioma brains (NGBs) as controls.ResultsUnsupervised clustering analyses delineated predominant 34-myeloid cell clusters (~75%) over 28-lymphoid cell clusters (~25%) reflecting enormous heterogeneity within and across glioma subtypes. The glioma immune diversity spanned functionally imprinted phagocytic, antigen-presenting, hypoxia, angiogenesis and, tumoricidal myeloid to classical cytotoxic lymphoid subpopulations. Specifically, IDH-mutant gliomas were predominantly enriched for brain-resident microglial subpopulations in contrast to enriched bone barrow-derived infiltrates in IDH-wild type especially in a recurrent setting. Microglia attrition in IWP and IWR gliomas were concomitant with invading monocyte-derived cells with semblance to dendritic cell and macrophage like transcriptomic features. Additionally, microglial functional diversification was noted with disease severity and mostly converged to inflammatory states in IWR gliomas. Beyond dendritic cells, multiple antigen-presenting cellular states expanded with glioma severity especially in IWP and IWR gliomas. Furthermore, we noted differential microglia and dendritic cell inherent antigen presentation axis viz, osteopontin, and classical HLAs in IDH subtypes and, glioma-wide non-PD1 checkpoints associations in T cells like Galectin9 and Tim-3. As a general utility, our immune cell deconvolution approach with single-cell-matched bulk RNA sequencing data faithfully resolved 58-cell states which provides glioma specific immune reference for digital cytometry application to genomics datasets.ConclusionsAltogether, we identified prognosticator immune cell-signatures from TCGA cohorts as one of many potential immune responsiveness applications of the curated signatures for basic and translational immune-genomics efforts. Thus, we not only provide an unprecedented insight of glioma TIME but also present an immune data resource that can be exploited for immunotherapy applications.Ethics ApprovalThe brain tumor/tissue samples were collected as per MD Anderson internal review board (IRB)-approved protocol numbers LAB03-0687 and, LAB04-0001. One non-tumor brain tissue sample was collected from patient undergoing neurosurgery for epilepsy as per Baylor College of Medicine IRB-approved protocol number H-13798. All experiments were compliant with the review board of MD Anderson Cancer Center, USA.ConsentWritten informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal

scholarly journals Small amounts of superantigen, when presented on dendritic cells, are sufficient to initiate T cell responses.

1993 ◽  
Vol 178 (2) ◽  
pp. 633-642 ◽  
Author(s):  
N Bhardwaj ◽  
J W Young ◽  
A J Nisanian ◽  
J Baggers ◽  
R M Steinman
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
Mhc Class Ii ◽  
Cell Receptor ◽  
Class Ii ◽  
Cell Mediated Immunity ◽  
Quiescent T Cells ◽  
Antigen Presenting

Dendritic cells are potent antigen-presenting cells for several primary immune responses and therefore provide an opportunity for evaluating the amounts of cell-associated antigens that are required for inducing T cell-mediated immunity. Because dendritic cells express very high levels of major histocompatibility complex (MHC) class II products, it has been assumed that high levels of ligands bound to MHC products ("signal one") are needed to stimulate quiescent T cells. Here we describe quantitative aspects underlying the stimulation of human blood T cells by a bacterial superantigen, staphylococcal enterotoxin A (SEA). The advantages of superantigens for quantitative studies of signal one are that these ligands: (a) engage MHC class II and the T cell receptor but do not require processing; (b) are efficiently presented to large numbers of quiescent T cells; and (c) can be pulsed onto dendritic cells before their application to T cells. Thus one can relate amounts of dendritic cell-associated SEA to subsequent lymphocyte stimulation. Using radioiodinated SEA, we noted that dendritic cells can bind 30-200 times more superantigen than B cells and monocytes. Nevertheless, this high SEA binding does not underlie the strong potency of dendritic cells to present antigen to T cells. Dendritic cells can sensitize quiescent T cells, isolated using monoclonals to appropriate CD45R epitopes, after a pulse of SEA that occupies a maximum of 0.1% of surface MHC class II molecules. This corresponds to an average of 2,000 molecules per dendritic cell. At these low doses of bound SEA, monoclonal antibodies to CD3, CD4, and CD28 almost completely block T cell proliferation. In addition to suggesting new roles for MHC class II on dendritic cells, especially the capture and retention of ligands at low external concentrations, the data reveal that primary T cells can generate a response to exceptionally low levels of signal one as long as these are delivered on dendritic cells.

scholarly journals 714 Selective expansion of antigen-specific CD8 T cells with engineered antigen presenting exosome

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A743-A743
Author(s):  
Tomoyoshi Yamano ◽  
Xiabing Lyu ◽  
Rikinari Hanayama
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Cd8 T Cells ◽  
Costimulatory Molecule ◽  
Animal Experiments ◽  
Surface Proteins ◽  
Hek293 Cells ◽  
Target Cells ◽  
Single Chain ◽  
Antigen Presenting

BackgroundExosomes are vesicular granules of about 100 nm and are secreted by many types of cells. Exosomes contain various proteins, lipids, and RNAs that are transported to target cells which induce functional and physiological changes. Exosomes are promising nano-vesicles for clinical application, owing to their high biocompatibility, low immunogenicity, and high drug delivery efficacy. Recent studies have demonstrated that exosomes from tumor cells or antigen presenting cells (APCs) regulate immune responses. Tumor derived exosomes express PD-L1 on their surface and suppress tumor immunity systemically. On the other hand, mature dendritic cells derived exosomes exert immune activation, and tumor immunotherapy using DCs exosome has been developed. However, few studies have been found to exert a significant effect on cancer treatment, may be because of low expression of costimulatory molecules and lack of cytokines on DCs derived exosomes.MethodsIt has been demonstrated that GFP can be conveyed into exosomes by conjugating GFP with tetraspanins, exosome-specific surface proteins. First, we generated a tetraspanin fusion protein with a single-chain MHCI trimer (scMHCI). IL-2 is inserted on the second extracellular loop of CD81, allowing robust and functional expression of IL-2 on the exosome. We collected exosomes from HEK293 cells culture, which stably express scMHCI-CD81-IL2 and CD80-MFGE8, and used as Antigen-presenting exosome(AP-Exo).ResultsAP-Exo expresses high expression of MHCI-peptide complex, costimulatory molecule, and cytokine, activating cognate CD8 T cells as dendritic cells do. AP-Exo selectively delivered co-stimulation and IL-2 to antigen-specific CD8 T cells, resulting in a massive expansion of antigen-specific CD8 T cells without severe adverse effects in mice. AP-Exo can expand endogenous tumor-specific CD8 T cells and induce the potent anti-tumor effect.ConclusionsOur strategy for building engineered exosomes that work like APCs might develop novel methods for cancer immunotherapy.Ethics ApprovalAll mice were housed in a specific pathogen-free facility, and all animal experiments were performed according to a protocol approved by Kanazawa University, Kanazawa, Japan.

scholarly journals Evaluation of Feline Monocyte-Derived Dendritic Cells Loaded with Internally Inactivated Virus as a Vaccine against Feline Immunodeficiency Virus

2008 ◽  
Vol 15 (3) ◽  
pp. 452-459 ◽  
Author(s):  
Giulia Freer ◽  
Donatella Matteucci ◽  
Paola Mazzetti ◽  
Francesca Tarabella ◽  
Valentina Catalucci ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Immune Responses ◽  
Immune Functions ◽  
Peripheral Blood Mononuclear ◽  
Challenge Virus ◽  
Homologous Virus ◽  
Antibody Titers ◽  
Cellular Immune ◽  
Antigen Presenting

ABSTRACT Dendritic cells are the only antigen-presenting cells that can present exogenous antigens to both helper and cytolytic T cells and prime Th1-type or Th2-type cellular immune responses. Given their unique immune functions, dendritic cells are considered attractive “live adjuvants” for vaccination and immunotherapy against cancer and infectious diseases. The present study was carried out to assess whether the reinjection of autologous monocyte-derived dendritic cells loaded with an aldithriol-2-inactivated primary isolate of feline immune deficiency virus (FIV) was able to elicit protective immune responses against the homologous virus in naive cats. Vaccine efficacy was assessed by monitoring immune responses and, finally, by challenge with the homologous virus of vaccinated, mock-vaccinated, and healthy cats. The outcome of challenge was followed by measuring cellular and antibody responses and viral and proviral loads and quantitating FIV by isolation and a count of CD4+/CD8+ T cells in blood. Vaccinated animals exhibited clearly evident FIV-specific peripheral blood mononuclear cell proliferation and antibody titers in response to immunization; however, they became infected with the challenge virus at rates comparable to those of control animals.

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