Dendritic Cell Activation Assay

• Dendritic cells (DCs) function as an intermediary between the innate and adaptive arms of the immune system. These sentinels play a pivotal role in the recognition, engulfment, and presentation of antigenic material to T-lymphocytes as well as the maintenance of immune homeostasis and self-tolerance.
• Their subsets are numerous and vary both functionally and phenotypically depending on their location in vivo. DCs isolated from the peripheral blood supply are broadly classified as myeloid or plasmacytoid in designation; however, they typically only represent 0.5-1.5% of the total cell population¹ and this limits their application for the purposes of in vitro screening.
• Monocyte-derived DCs (moDCs) generated from cells isolated from peripheral blood not only provide an abundant source of immunocompetent cells but also a robust in vitro model with which to assess the immunogenic potential of myriad therapeutic modalities. These include biologics, oligonucleotides, and small molecules.^2-4
• This in vitro approach can also be used to evaluate the efficacy and safety of vaccines and adjuvants using a high-throughput workflow.³ The advantages of such an approach include a reduction in the use of animal models and the time taken to assess the suitability of a potential candidate.
• Our high-throughput screening platform uses moDCs to assess innate immune activation by measuring key biomarkers such as pro-inflammatory cytokine release in conjunction with cell viability.
• Our on-site biobank currently houses a wide diversity of HLA-typed moDCs isolated from the blood of healthy, human donors. Screening test articles using multiple donors allows inter-individual and population-wide responses to be evaluated, thereby increasing the accuracy of the assay result.
• Our assay uses LPS EK as a positive control which is a potent activator of DCs and elicits a strong pro-inflammatory response via interaction with TLR2 & 4.^5,6 This forms part of our integral quality control measures and serves as an indicator of optimal assay performance.

_{1) Hasskamp JH et al., (2005). Dendritic Cell Counts in the Peripheral Blood of Healthy Adults. Am. J. Hematol. 78; 314–315
2) Morgan H et al., (2019). Evaluation of in vitro Assays to Assess the Modulation of Dendritic Cells Functions by Therapeutic Antibodies and Aggregates. Front. Immunol. 10
3) Vandebriel R & Hoefnagel MM (2012). Dendritic cell-based in vitro assays for vaccine immunogenicity. Hum. Vaccin. Immunother. 8(9); 1323-1325
4)  Galbiati V et al., (2016). In vitro Models to Evaluate Drug-Induced Hypersensitivity: Potential Test Based on Activation of Dendritic Cells. Front. Pharmacol. 7
5)  Rossol M et al., (2011). LPS-induced cytokine production in human monocytes and macrophages. Crit. Rev. Immunol. 31(5); 379-446
6)  Abdi K et al., (2012). LPS Activated Dendritic cells: “Exhausted” or alert and waiting? DCs: “Exhausted”, alerted or waiting? J. Immunol. 88(12); 5981–5989}