Speaker
Description
"Human long-lived plasma cells (LLPCs) are terminally differentiated effector cells of the B-lymphocyte lineage that reside in specialized niches in the human bone marrow (BM) harboring many different microenvironmental niches. LLPCs play an essential role in the humoral immune protection by maintaining constant high-affinity antibody levels against pathogens and their toxic products, independently of antigen presence. So far, the in vitro long-term cultivation of BM LLPCs is challenging since they reveal a brief survival time ex vivo. Thus, this project aims to develop an in vitro model that mimics the physiological microenvironment of their niche in the BM and enables long-term cultivation of LLPCs.
Our previously developed 3D model based on a hydroxyapatite-coated zirconium oxide-based ceramic can be used to maintain hematopoietic stem and progenitor cells for up to 8 weeks in their undifferentiated state (CD34+CD38-) when co-cultivated with BM mesenchymal stromal cells (MSCs) (Sieber et al. 2018). Based on this data, we aim to adapt the model to establish a microenvironment to support the survival of functional LLPCs in vitro. Human plasma cells (PCs) (CD38+CD138+) are isolated via magnetic activated cell sorting (MACS) from femoral head after mechanical preparation and introduced into the ceramic pre-seeded with MSCs building up a BM microenvironment. The survival capacity of functional PCs is assessed by flow cytometric analysis and detection of secreted antibodies by Bioplex.
So far, we are able to maintain PCs for up to 21 days in our in vitro system built up by the 3D scaffold pre-seeded with MSCs. Due to limitations of efficient extraction of PCs embedded in the 3D microenvironment after cultivation for flow cytometric analyses, their survival is shown indirectly by making use of their ability to secrete immunoglobulins. The cultured PCs remain functional and maintain their ability to secrete immunoglobulins (IgG1, IgA, IgM) over the culture time.
The established survival niche model could serve as a system to study niche interactions and will pave the way to establish disease models for diseases like multiple myeloma or autoimmunity to analyze changes in the microenvironment that promote the maintenance of pathogenic PCs. The better understanding of survival mechanisms of pathogenic PCs could disclose new targets for specific therapies."
62825476779
