Detection of differentiation- and activation-linked cell surface antigens on cultured mast cell progenitors


P. Valent MD
Department of Internal Medicine I
Division of Hematology and Hemostaseology
Medical University of Vienna
Währinger Gürtel 18–20
A-1090 Vienna


Background:  Mast cells (MC) are multifunctional effector cells of the immune system. They derive from uncommitted CD34+ hemopoietic progenitor cells (HPC). Depending on the stage of maturation and the environment, MC variably express differentiation- and activation-linked antigens. Little is known, however, about the regulation of expression of such antigens in immature human MC.

Methods:  We analyzed expression of CD antigens on human MC grown from cord blood-derived CD34+ HPC. The HPC were isolated by magnetic cell sorting (MACS) and FACS to >97% purity, and were cultured in stem cell factor (SCF) and interleukin (IL)-6 with or without additional cytokines (IL-4 or IL-10) in serum-free medium. The cell surface phenotype of MC was determined by monoclonal antibodies and flow cytometry.

Results:  Cultured MC progenitors were found to react with antibodies against various CD antigens including CD58, CD63, CD117, CD147, CD151, CD203c, and CD172a, independent of the growth factors used and time-point investigated (days 14–42). CD116 [granulocyte–macrophage colony-stimulating factor receptor α (GM-CSFRα)] and CD123 (IL-3Rα) were expressed on MC precursors on day 14, but disappeared thereafter. Cultured MC did not express CD2, CD3, CD5, CD10, CD19, or CD25. Addition of IL-10 to MC cultures showed no effect on expression of CD antigens. However, IL-4 was found to promote expression of CD35 and CD88 on cultured MC without changing expression of other CD antigens.

Conclusions:  Most MC antigens may already be expressed at an early stage of mastopoiesis. Whereas IL-3R and GM-CSFRs are lost during differentiation of MC, these cells may acquire complement receptors (CD35, CD88) under the influence of distinct cytokines.