TY - JOUR
T1 - Regulation of FcεRI expression during murine basophil maturation
T2 - The interplay between IgE, cell division, and FcεRI synthetic rate
AU - Zaidi, Asifa K.
AU - MacGlashan, Donald W.
PY - 2010/2/1
Y1 - 2010/2/1
N2 - Expression of FcεRI on basophils and mast cells is modulated by IgE Ab. Previous studies have noted in vivo receptor expression dynamics that are discordant with expectations derived from in vitro studies. The current study presents a formal hypothesis to explain the discordant observations and tests two assumptions that underlie a proposed model of receptor dynamics. After first showing that a murine model of receptor expression on basophils recapitulates observations made using human basophils, the effect of changes in IgE on basophil egress rates was examined. In the proposed model, egress rates from bone marrow (BM) were assumed to be unaffected by changes in IgE concentration. Egress was tested by examining the labeling of BM and peripheral blood (BL) basophils at various times after injection of BrdU with and without injection with IgE. The IgE Ab did not alter the appearance of BrdU label in peripheral BL basophils. In addition, BM and BL basophils were responsive to the elevations in IgE, with receptor expression increasing on BM basophils before BL basophils. It was also noted that BL basophils expressed ∼50% of the receptor density of BM basophils. There was a 3-fold greater synthetic rate of FcεRI on BM basophils that readily explained the difference. These results provide support for the proposed hypothesis of rapid changes in receptor expression being controlled by cell replacement. The studies also support a model whereby receptor expression is limited by cell division and that basophils, once mature, slow their rate of receptor synthesis.
AB - Expression of FcεRI on basophils and mast cells is modulated by IgE Ab. Previous studies have noted in vivo receptor expression dynamics that are discordant with expectations derived from in vitro studies. The current study presents a formal hypothesis to explain the discordant observations and tests two assumptions that underlie a proposed model of receptor dynamics. After first showing that a murine model of receptor expression on basophils recapitulates observations made using human basophils, the effect of changes in IgE on basophil egress rates was examined. In the proposed model, egress rates from bone marrow (BM) were assumed to be unaffected by changes in IgE concentration. Egress was tested by examining the labeling of BM and peripheral blood (BL) basophils at various times after injection of BrdU with and without injection with IgE. The IgE Ab did not alter the appearance of BrdU label in peripheral BL basophils. In addition, BM and BL basophils were responsive to the elevations in IgE, with receptor expression increasing on BM basophils before BL basophils. It was also noted that BL basophils expressed ∼50% of the receptor density of BM basophils. There was a 3-fold greater synthetic rate of FcεRI on BM basophils that readily explained the difference. These results provide support for the proposed hypothesis of rapid changes in receptor expression being controlled by cell replacement. The studies also support a model whereby receptor expression is limited by cell division and that basophils, once mature, slow their rate of receptor synthesis.
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U2 - 10.4049/jimmunol.0901865
DO - 10.4049/jimmunol.0901865
M3 - Article
C2 - 20042574
AN - SCOPUS:77949319896
SN - 0022-1767
VL - 184
SP - 1463
EP - 1474
JO - Journal of Immunology
JF - Journal of Immunology
IS - 3
ER -