Generation of Functionally Competent Human Mast Cells from Limited Blood Volumes

Area of Science:

• Immunology
• Cell Biology

Background:

• Mast cells (MCs) are crucial innate immune cells originating from hematopoietic stem/progenitor cells (HSPCs).
• Generating mature MCs from peripheral blood typically requires large blood volumes due to low HSPC frequencies.

Purpose of the Study:

• To validate a novel in-house protocol for generating MCs from limited peripheral blood volumes (<20 mL).

Main Methods:

• Isolation of 'untouched' HSPCs from 14-16 mL peripheral blood using magnetic bead-based procedures.
• Expansion of HSPCs for 4 weeks, followed by 8 weeks of culture in MC maturation medium.
• Phenotypic and functional characterization using flow cytometry, histochemical staining, and degranulation assays.

Main Results:

• Generated MCs (PB-MCs) exhibited comparable expression of cytoplasmic granules and cell-surface markers (MRGPRX2, FcεR1α, CD117) to buffy coat-derived MCs (BC-MCs).
• PB-MCs demonstrated functional competence, responding to stimulation with IgE/anti-IgE and C48/80.
• The protocol successfully yielded functionally competent MCs after 12 weeks of in vitro culture.

Conclusions:

• The developed protocol efficiently generates functionally competent mast cells from small peripheral blood volumes.
• This method offers a viable alternative for MC generation without compromising maturation or activation potential.
• The protocol overcomes the limitation of large blood volumes previously required for MC generation.