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HemaCare Memory B Cells Recall Their Primary Function

Jan 8, 2019 9:59:00 AM / by Nancy Andon, MSc

Memory chip-1Global biotechnology company Immunospot cites using B cells isolated from HemaCare-sourced peripheral blood mononuclear cells (PBMC) [1] for their studies on post-cryopreservation functionality.

Expectations are high that emerging field of cell therapy will be able to deliver breakthrough treatments or cures for many diseases, including cancer. One of the most powerful facets of this new medical field is the concept of immunotherapy--using the body’s own immune cells to specifically target disease. Immune cell function is at the heart of this concept, so keeping immune cells fully operational is crucially important. In this recent study published in the journal Cells, biopharmaceutical scientists aim to investigate B cell functionality following cryopreservation.

The primary function of B cells is to recognize antigens from invading pathogens and mount an immune response. Once a naive B cell is activated by antigens, it will proliferate, with new cells transforming into either short lived “plasmablast” cells that are part of an immediate immune defense, or more rarely into long-lived “memory” cells, that will secrete antibodies only while the antigen is present. B memory cells can last for decades in a resting state, without producing antibodies. Once the cells are re-activated by the presence of the antigen they “memorized”, they will start secreting antibodies once more, as well as producing another flurry of short-lived plasmablasts and new memory cells to deal with the invading pathogen. Long term immunity is critically dependent on this ability of B cells to produce antibodies, and proliferate to form new plasmablast cells and memory cells following re-exposure to a specific antigen.

Unfortunately, historical evidence suggests that memory B cells do not recover well from cryopreservation [2], and are often unable to launch a sufficient immune response upon thawing. The authors used PBMC sourced from HemaCare to isolate B cells with which to test an optimized freezing and thawing protocol that they anticipated would successfully preserve memory B cell function. Results were recorded using a complex B cell assay that can detect all 4 antibody classes, and differentiate between memory B cell antibody secretion and plasmablast secretion.

Patients who have received immunotherapy are regularly monitored for their immune cell function following treatment. This is done by testing an immune cell enriched PBMC sample for the presence of various antibodies. Without the ability to effectively cryopreserve functionally intact PBMC samples, immune monitoring of immunotherapy patients could only be done on freshly isolated PBMCs, making it all but impossible to conduct large clinical trials or commercialize treatments involving these cells. Being able to detect the presence of newly activated plasmablasts in cryopreserved PBMC samples provides proof of concept for using cryopreserved PBMCs for monitoring immune function.  This capability will allow for the large-scale immune monitoring needed to support a globally manufactured immunotherapy product.

References:

  1. Fecher P., et al. B cells and B cell Blasts Withstand Cryopreservation While Retaining Their Functionality for Producing Antibody. Cells. 7(50). May 2018.
  2. Naor D., and O’Toole C. Cryopreservation of immunological memory and other lymphoid cell functions. Journal of Immunological Methods. 16(4); 361-370. May 1977.

Topics: Cryopreservation, Immunotherapy

Nancy Andon, MSc

Written by Nancy Andon, MSc

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