Immune monitoring technology primer: immunoprofiling of antigen-stimulated blood

Description of the technology Compelling evidence from several studies on the immune contexture of the tumor has revealed that infiltration by specific leukocyte cell subsets with specific cytokine signatures is linked with favorable outcomes in a variety of different cancers [1, 2]. Given the potential burden and limitation of repeat biopsies, there is a need for non-invasive techniques to complement the characterization of the immune contexture within the tumor and provide prognostic biomarkers for use in clinical immune monitoring. Advances in genomics, proteomics and metabolomics offer promise but have not yet translated to significant progress in this area. Nevertheless circulatory immunological biomarkers could potentially aid clinical decision-making regarding initiation, cessation, escalation or change of treatment and assessment of therapeutic responses. Moreover, in the context of immunotherapy, immunological biomarkers could serve as indicators of immunological competence and therefore susceptibility to immune-based therapies. As the success of immunotherapies is dependent on a functioning immune system and the development and/or restoration of anti-tumor adaptive immune responses, determining the level of the patient immune competency prior to or during immunotherapy may be critical. This assessment can be based on changes in secretion of both T-cell derived or APC-secreted cytokines and chemokines under specific stimulatory conditions and may ultimately help guide clinical choices. The TruCulture® system is a syringe-based device designed for point of care use, allowing for sterile collection of whole blood (Fig. 1). The tube contains 1 ml of cell culture medium which may include a variety of immunological stimulants aimed at different cell subsets (Table 1). In these tubes, similar to blood collection tubes, 1 ml of whole blood is drawn in and mixed with the medium. Control tubes with no stimulants to assess background levels of mediators of interest are included. The tube is incubated at 37 °C in a dry heat-block for 24 to 48 h. After incubation, cells are separated by a valve separator component. The supernatant, now free of cells, is stored at −80 °C until analysis. This process does not require access to laboratory equipment such as sterile hood, CO2 incubator, centrifuge etc. or specialized training, so it has the potential to become a research tool easily integrated into clinical trial protocols and performed at point of care by nursing staff. This technique may be considered an improvement over the more involved laboratory processes used to obtain Peripheral Blood Mononuclear Cells (PBMC) for in vitro culture or over whole blood stimulation assays. Compared to PBMC assays, the TruCulture® accurately represents responsiveness to immune stimuli by human whole blood immune cells as it maintains in its mix all type of immune cells present in the blood, including granulocytes and platelets. Moreover, it is not dependent on cryopreservation as it is often the case with PBMC assays. Furthermore, by relying on a self-enclosed tube is not susceptible to contamination during handling. The available experimental data provided by the manufacturer indicate that the number of cytokines and their secreted levels are similar between TruCulture® and PBMC assays [3]. Compared to whole blood stimulation assays which rely on a relatively short time in culture, the longer incubation periods of the TruCulture® system permits investigation of processes involving both de novo * Correspondence: lrb@immodulon.com Immodulon Therapeutics Ltd, Stockley Park 6-9 The Square, Uxbridge UB11 1FW, UK Full list of author information is available at the end of the article