Ex vivo antigen-pulsed PBMCs generate potent and long lasting immunity to infection when administered as a vaccine

CircRNAs in tumor immunity and immunotherapy: Perspectives from innate and adaptive immunity

Tumor immunotherapy is a new therapeutic approach that has been evolving in the last decade and has dramatically changed the treatment options for cancer. Circular RNAs (circRNAs) are non-coding RNAs (ncRNAs) with high stability, tissue-specific and cell-specific expression. There is growing evidence that circRNAs are involved in the regulation of both adaptive and innate immunity. They play important roles in tumor immunotherapy by affecting macrophage, NK and T cell function. The high stability and tissue specificity make them ideal candidate biomarkers for therapeutic effects. CircRNAs also represent one of promising targets or adjuvant for immunotherapy. Investigations in this field progress rapidly and provide essential support for the diagnosis, prognosis and treatment guidance of cancers in the future. In this review, we summarize the role of circRNAs on tumor immunity from the viewpoint of innate and adaptive immunity, and explore the role of circRNAs in tumor immunotherapy.

Fibrocytes: A Critical Review and Practical Guide

Fibrocytes are hematopoietic-derived cells that directly contribute to tissue fibrosis by producing collagen following injury, during disease, and with aging. The lack of a fibrocyte-specific marker has led to the use of multiple strategies for identifying these cells in vivo. This review will detail how past studies were performed, report their findings, and discuss their strengths and limitations. The motivation is to identify opportunities for further investigation and promote the adoption of best practices during future study design.

Preventive cancer vaccination with P5 HER-2/neo-derived peptide‐pulsed peripheral blood mononuclear cells in a mouse model of breast cancer

This study compared the prophylactic effects from vaccines based on dendritic cells (DCs) and peripheral blood mononuclear cells (PBMCs) by pulsing the cells in-vitro with p5 peptide. The different test groups of mice were injected with free peptide or with peptide pulsed with DCs or PBMCs. Two weeks after the last booster dose, immunological tests were performed on splenocyte suspensions from three mice in each group and the remaining mice (5/each group) were evaluated for tumor growth and survival time. The levels of IFN-γ, granzyme B, and IL-10 were detected in T cells. Additionally, IFN-γ and perforin as well as mRNA levels of some genes associated with immune responses were assessed after challenging the splenocytes with TUBO cells. A significant increase was observed in frequency of CD4+ IFN-γ+, CD8+ IFN-γ+, and CD8+ granzyme B+ T cells, and the perforin of supernatants from mice in the DC and PBMC treatment groups. Significant expression levels of Fas ligand (FasL) and forkhead box P3 (Foxp3) were observed in the DC and PBMC groups. These responses led to smaller tumors and longer survival time in our mouse model of breast cancer. The efficacy of the PBMC-based vaccine in improving the protective immune response makes it a simpler and less expensive candidate vaccine compared with DC-based vaccines.

Optimization of a Density Gradient Centrifugation Protocol for Isolation of Peripheral Blood Mononuclear Cells

Objective: Peripheral blood mononuclear cells (PBMC) are extremely important in the body’s immune response. Their isolation represents a major step in many immunological experiments. In this two phase study, we aimed to establish an optimum protocol for PBMC isolation by density-gradient centrifugation.

Methods: During Phase-1, we compared two commercially available PBMC isolation protocols, Stemcell Technologies (ST) and Miltenyi Biotec (MB), in terms of PBMC recovery and purity. Twelve blood samples were assigned to each protocol. Each sample was divided in three subsamples of 1ml, 2ml and 3ml in order to assess the influence of blood sample volume on isolation performance. During Phase-2, a hybrid protocol was similarly tested, processing six blood samples. Additionally, we performed a flow cytometric analysis using an Annexin-V/Propidium-Iodide viability staining protocol.

Results: Phase-1 results showed that, for all subsample volumes, ST had superior PBMC recovery (mean values: 56%, 80% and 87%, respectively) compared to MB (mean values: 39%, 54% and 43%, respectively). However, platelet removal was significantly higher for MB (mean value of 96.8%) than for ST (mean value of 75.2%). Regarding granulocyte/erythrocyte contamination, both protocols performed similarly, yielding high purity PBMC (mean values: 97.3% for ST and 95.8% for MB). During Phase-2, our hybrid protocol yielded comparable results to MB, with an average viability of 89.4% for lymphocytes and 16.9% for monocytes.

Conclusions: ST yields higher cell recovery rates and MB excels at platelet removal, while the hybrid protocol is highly similar to MB. Both cell recovery and viability increase with blood sample volume.