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ORIGINAL RESEARCH
Optimization of human B cell culture conditions for expansion of activated or differentiated B cells
Pirogov Russian National Research Medical University, Moscow, Russia
Correspondence should be addressed: Irina L. Grigorova
Ostrovityanova, 1, Moscow, 117997, Russia; moc.liamg@67girg
Funding: the study was supported by the Russian Science Foundation (grant No. 24-15-00545).
Acknowledgements: the authors express their gratitude to E. Zakatina for assistance in manuscript editing.
Author contribution: Grigorova IL — study design, concept of the article, editing, approval of the final version of the article; Sokolova SR — experimental procedure, processing of the results, manuscript writing.
Compliance with ethical standards: the study was approved by the Ethics Committee of the Pirogov Russian National Research Medical University (protocol No. 240 date 23 May 2024). All subjects signed the informed consent for participation in the study.
In vitro B cell cutures are important for fundamental and applied science: these can be used to study antigenic specificity of B and T cells, as well as to produce monoclonal antibodies and other biopharmaceuticals. That is why the development of an optimal protocol for culturing of activated B cells, antibody-secreting cells (ASCs), and germinal center (GC) B cells in vitro remains an urgent task. The study aimed to find the conditions ensuring the following: high B cell expansion and survival rates, ASC accumulation, GC B cell production and accumulation. For that the CD27‒ and/or CD27+ B cells from human peripheral blood were cultured in the presence of the feeder 3T3-hCD40L line, various combinations of cytokines (IL21, IL4, BAFF), human serum components or under the control conditions throughout 7 days. Flow cytometry analysis of B cell cultures showed that the CD40L and IL21 co-existence was essential for achieving high B cell expansion, survival, and differentiation with the production of the CD27highCD38high ASCs and CD95highBcl-6+ GC-like cells. The highest expansion was observed in the cultures of CD27 naïve cells in the presence of human serum components. The IL4 supplementation moderately increased the share of GC-like cells. The maximum ASC accumulation was observed in the cultures of CD27+ memory В cells. The approach developed made it possible to find the optimal conditions for in vitro B cell culturing and clearly demonstrated the impact of both individual IL-21, IL-4, BAFF cytokines and their combinations on the B cell cultures of various subpopulations.
Keywords: B cells, antibody-secreting cells (ASCs), germinal center (GC) B cells, human lymphocytes cultures in vitro, 3T3-hCD40L